Please remember to add a category to the bottom of each page that you create.
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Difference between revisions of "XDA-Developers:Android"

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{{Infobox OS
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Android is an operating system for mobile devices such as cellular phones, tablet computers and netbooks. Android was developed by Google and based upon the Linux kernel and GNU software. It was initially developed by Android Inc. (a firm later purchased by Google) and lately by the Open Handset Alliance.[4] According to NPD Group, unit sales for Android OS smartphones ranked second among all smartphone OS handsets sold in the U.S. in the first quarter of 2010.[5][6] BlackBerry OS holds 36% and iOS holds 21% ranked first and third respectively with Android at second with 28%.[7] A Nielsen report for the same quarter placed Android in fourth place with 9% of the market.[8][9]
| name                  = Android
+
Android has a large community of developers writing apps that extend the functionality of the devices. There are currently over 70,000 apps available for Android, which makes it the second most popular mobile development target.[10] Developers write managed code in the Java language, controlling the device via Google-developed Java libraries.[11]
| logo                  = [[File:Android logo.svg|100px]]
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The unveiling of the Android distribution on 5 November 2007 was announced with the founding of the Open Handset Alliance, a consortium of 71 hardware, software, and telecom companies devoted to advancing open standards for mobile devices.[12][13] Google released most of the Android code under the Apache License, a free software and open source license.[14]
| screenshot            = [[File:Android-2.2.png|250px]]
+
The Android operating system software stack consists of Java applications running on a Java based object oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore[15] media framework, SQLite relational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc. The Android operating system consists of 12 million lines of code including 3 million lines of XML, 2.8 million lines of C, 2.1 million lines of Java, and 1.75 million lines of C++.[16]
| caption                = Android 2.2
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Contents [hide]
| working_state          = Current
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1 History
| source_model          = [[Free and open source software]]
+
1.1 Early acquisition by Google
| released              = {{Start date|2008|10|21|df=yes}}
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1.2 Open Handset Alliance
| latest_release_version = 2.2 (Froyo)
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1.3 Licensing
| latest_release_date    = {{Start date and age|2010|05|20|df=yes}}<ref name="froyo-goodies">{{cite web | url = http://android-developers.blogspot.com/2010/05/android-22-and-developers-goodies.html | work = Android Developers Blog | title = Android 2.2 and developers goodies. | publisher = [[Google]] | accessdate = 2010-05-20 | first = Xavier | last = Ducrohet | date = 20 May 2010}}</ref>
+
1.4 Update history
| website                = [http://www.android.com/ android.com]
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2 Features
| developer              = [[Open Handset Alliance]]
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3 Hardware running Android
| license                = [[Apache License|Apache]] 2.0 and [[GNU General Public License|GPL]]<nowiki>v2</nowiki><ref name="Licenses">{{cite web
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4 Software development
| url = http://source.android.com/source/licenses.html
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4.1 Software development kit
| title=Licenses
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4.2 App Inventor for Android
| work = Android Open Source Project
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4.3 Android Developer Challenge
| publisher = [[Open Handset Alliance]]
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4.4 Google applications
| accessdate = 2010-06-10
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4.5 Third party applications
}}</ref>
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4.6 Native code
| kernel_type            = [[Monolithic kernel|Monolithic]] (modified [[Linux kernel]])
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4.7 Community-based firmware
| ui                    = [[Graphical User Interface|Graphical]]
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5 Marketing
| supported_platforms    = [[ARM architecture|ARM]], [[MIPS architecture|MIPS]], [[Power Architecture]], [[x86]]
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5.1 Logos
| programmed_in          = [[C (programming language)|C]] (core)<ref>{{cite web
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5.2 Typeface
| url = http://www.lextrait.com/Vincent/implementations.html
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5.3 Market share
| title = The Programming Languages Beacon, v10.0
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6 Restrictions and issues
| first = Vincent | last = Lextrait
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6.1 Linux compatibility
| month = January
+
6.2 Networking issues
| year = 2010
+
6.3 Issues concerning application development
| accessdate = 5 January 2010
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6.4 Time zones
}}</ref>, [[C++]] (some third party libraries), [[Java (programming language)|Java]] (UI)
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7 See also
| updatemodel            =
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8 References
| package_manager        =
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9 Bibliography
}}
+
10 External links
 
+
[edit]History
'''Android''' is an [[mobile operating system|operating system]] for [[mobile devices]] such as [[cellular phones]], [[tablet computers]] and [[netbooks]]. Android was developed by [[Google]] and based upon the [[Linux kernel]] and [[GNU]] software. It was initially developed by Android Inc. (a firm later purchased by [[Google]]) and lately by the [[Open Handset Alliance]].<ref name="AndroidAnnouncement">{{cite press release |url=http://www.openhandsetalliance.com/press_110507.html |title=Industry Leaders Announce Open Platform for Mobile Devices |accessdate=2007-11-05 |date=2007-11-05 |publisher=[[Open Handset Alliance]]}}</ref>  According to [[NPD Group]], unit sales for Android OS smartphones ranked second among all [[smartphone]] OS handsets sold in the U.S. in the first quarter of 2010.<ref>{{cite web |url= http://www.reuters.com/article/idUSLDE64I03620100519 |title= Google beats Microsoft in smartphones |date= 2010-05-19 |accessdate= 2010-06-11}}</ref><ref>{{cite web |url= http://mediamemo.allthingsd.com/20100510/is-android-really-outselling-apple |title=Is Android Really Outselling Apple? |author= Peter Kafka |date= 2010-05-10 |accessdate= 2010-06-11}}</ref> [[BlackBerry OS]] holds 36% and [[iOS (Apple)|iOS ]]holds 21% ranked first and third respectively with Android at second with 28%.<ref>{{cite web |url= http://www.engadget.com/2010/05/10/npd-android-ousts-iphone-os-for-second-place-in-us-smartphone-m/ |title= NPD: Android ousts iPhone OS for second place in US smartphone market |author=  Donald Melanson |date= 2010-05-10 |accessdate= 2010-06-11}}</ref> A Nielsen report for the same quarter placed Android in fourth place with 9% of the market.<ref>{{cite web |url= http://blog.nielsen.com/nielsenwire/online_mobile/iphone-vs-android/ |title=iPhone vs. Android? |author= Nielsen |date= 2010-06-04 |accessdate= 2010-06-04}}</ref><ref>http://www.telecoms.com/20036/something-for-everyone/</ref>
+
 
+
Android has a large community of developers writing [[application software|app]]s that extend the functionality of the devices. There are currently over 70,000 apps available for Android, which makes it the second most popular mobile development target.<ref>http://www.pcmag.com/article2/0,2817,2366624,00.asp</ref>  Developers write [[managed code]] in the [[Java (programming language)|Java language]], controlling the device via Google-developed Java libraries.<ref>{{cite news |url=http://www.news.com/8301-13580_3-9815495-39.html | title=Google's Android parts ways with Java industry group |work=[[CNET News]] |first=Stephen |last=Shankland |date=12 November 2007}}</ref>
+
 
+
The unveiling of the Android distribution on 5 November 2007 was announced with the founding of the [[Open Handset Alliance]], a consortium of 71 [[Computer hardware|hardware]], [[Computer software|software]], and [[Telecommunication|telecom]] companies devoted to advancing [[open standard]]s for mobile devices.<ref name="OHAhome">{{cite web |url=http://www.openhandsetalliance.com/ |title=Open Handset Alliance | accessdate=2010-06-10 |publisher=Open Handset Alliance}}</ref><ref>{{cite news | url = http://phandroid.com/2008/12/10/sony-ericsson-htc-androids-set-for-summer-2009/ | title = Sony Ericsson, HTC Androids Set For Summer 2009 | work = Android Phone Fans | first = Rob | last = Jackson | date = 10 December 2008 | accessdate = 2009-09-03}}</ref> Google released most of the Android code under the [[Apache License]], a [[Free software license|free software]] and [[open source license]].<ref name="AndroidOverview">{{cite web|url=http://www.openhandsetalliance.com/android_overview.html|publisher=Open Handset Alliance|accessdate=2008-09-23|title=Android Overview}}</ref>
+
 
+
The Android operating system [[software stack]] consists of [[Java (programming language)|Java applications]] running on a Java based [[Object-oriented|object oriented]] [[application framework]] on top of [[Java Class Library|Java core libraries]] running on a [[Dalvik (software)|Dalvik virtual machine]] featuring [[Just-in-time compilation|JIT compilation]]. Libraries written in C include the surface manager, OpenCore<ref>{{cite web|url=http://www.opencore.net/|title=Open Core|accessdate=2010-06-03}}</ref> [[Multimedia framework|media framework]], [[SQLite]] relational [[Relational database management system|database management system]], [[OpenGL ES|OpenGL ES 2.0]] [[3D computer graphics|3D graphics]] [[Application programming interface|API]], [[WebKit|WebKit layout engine]], [[Skia Graphics Engine|SGL]] graphics engine, [[Transport Layer Security|SSL]], and [[GNU_C_Library#Use_in_small_devices|Bionic libc]]. The Android operating system consists of 12 million lines of code including 3 million lines of [[Xml|XML]], 2.8 million lines of [[C (programming language)|C]], 2.1 million lines of [[Java (programming language)|Java]], and 1.75 million lines of [[C++]].<ref>{{cite web|url=http://www.gubatron.com/blog/2010/05/23/how-many-lines-of-code-does-it-take-to-create-the-android-os/|title=How many lines of code does it take to create the Android OS?|author=Gubatron.com|date=23May2010|accessdate=2010-06-03}}</ref>
+
 
+
==History==
+
===Early acquisition by Google===
+
In July 2005, [[Google]] [[List of Google acquisitions|acquired]] Android, Inc., a small [[startup company]] based in [[Palo Alto, CA|Palo Alto, California, USA]].<ref name="AndroidInc">{{cite web |url=http://www.businessweek.com/technology/content/aug2005/tc20050817_0949_tc024.htm |title=Google Buys Android for Its Mobile Arsenal |accessdate=2007-11-07 |last=Elgin |first=Ben |date=2005-08-17 |publisher=Business Week}}</ref> Android's co-founders who went to work at Google included [[Andy Rubin]] (co-founder of [[Danger (company)|Danger]]),<ref name="AndyRubin">{{cite news |url=http://www.nytimes.com/2007/11/04/technology/04google.html?_r=2&hp=&pagewanted=all |title=I, Robot: The Man Behind the Google Phone |accessdate=2008-10-14 |last=Markoff |first=John |date=2007-11-04 |publisher=New York Times}}</ref> [[Rich Miner]] (co-founder of Wildfire Communications, Inc.),<ref>{{cite news | url=http://www.boston.com/business/technology/articles/2007/09/02/introducing_the_google_phone/ | title=Introducing the Google Phone | first=Scott | last=Kirsner | accessdate=2008-10-24 | work=[[The Boston Globe]]}}</ref> [[Nick Sears]] (once VP at [[T-Mobile]]),<ref name="Nick">{{cite press release |url=http://www.nokia.com/A4136002?newsid=918410 |title=T-Mobile Brings Unlimited Multiplayer Gaming to US Market with First Launch of Nokia N-Gage Game Deck |accessdate=2009-04-05 |date=23 September 2003 |publisher=Nokia}}</ref> and Chris White (headed design and interface development at [[WebTV]]).<ref>{{cite news |url=http://www.businessweek.com/technology/content/aug2005/tc20050817_0949_tc024.htm |accessdate=2009-04-23 |title=Google Buys Android for Its Mobile Arsenal |work=[[BusinessWeek]] |first=Ben |last=Elgin |date=17 August 2005}}</ref> At the time, little was known about the functions of Android, Inc. other than that they made software for mobile phones.<ref name="AndroidInc"/> This began rumors that Google was planning to enter the [[mobile phone]] market.
+
 
+
At Google, the team led by Rubin developed a mobile device platform powered by the [[Linux kernel]] which they marketed to handset makers and [[Mobile network operator|carriers]] on the premise of providing a flexible, upgradeable system. It was reported that Google had already lined up a series of hardware component and software partners and signaled to carriers that it was open to various degrees of cooperation on their part.<ref name="EngadgetMobileOS">{{cite web |url=http://www.engadget.com/2007/08/28/google-is-working-on-a-mobile-os-and-its-due-out-shortly/ |title=Google is working on a mobile OS, and it's due out shortly |accessdate=2007-11-06 |last=Block |first=Ryan |date=2007-08-28 |work=[[Engadget]]}}</ref><ref name="WSJ">{{cite web |url=http://online.wsj.com/article_email/SB118602176520985718-lMyQjAxMDE3ODA2MjAwMjIxWj.html |title=Google Pushes Tailored Phones To Win Lucrative Ad Market |accessdate=2007-11-06 |last1=Sharma |first1=Amol |first2=Kevin J. |last2=Delaney |date=2007-08-02 |work=[[The Wall Street Journal]]}}</ref><ref name="DT">{{cite web |url=http://www.directtraffic.org/OnlineNews/Google_admits_to_mobile_phone_plan_18094880.html |title=Google admits to mobile phone plan |accessdate=2007-11-06 |date=2007-03-20 |work=directtraffic.org |publisher=Google News}}</ref>
+
More speculation that Google would be entering the mobile-phone market came in December 2006.<ref name="McKay">{{cite news |last=McKay |first=Martha |date=21 December 2006 |title=Can iPhone become your phone?; Linksys introduces versatile line for cordless service |work=[[The Record (Bergen County)|The Record]] |page=L9 |quote=And don't hold your breath, but the same cell phone-obsessed tech watchers say it won't be long before Google jumps headfirst into the phone biz. Phone, anyone?}}</ref> Reports from the [[BBC]] and ''[[The Wall Street Journal]]'' noted that Google wanted its search and applications on mobile phones and it was working hard to deliver that. Print and online media outlets soon reported rumors that Google was developing a Google-branded [[Handset#Telephony|handset]].<ref name="LIgPhone">{{cite web |url=http://www.linuxinsider.com/rsstory/59115.html |title=Blogosphere Aflutter With Linux-Based phone Rumors |accessdate=2007-11-07 |last=Ackerman |first=Elise |date=2007-08-30 |work=Linux Insider}}{{Dead link|date=September 2009}}</ref> More speculation followed reporting that as Google was defining technical specifications, it was showing prototypes to cell phone manufacturers and network operators.
+
 
+
In September 2007, [[InformationWeek]] covered an [[Evalueserve]] study reporting that Google had filed several [[patent]] applications in the area of mobile telephony.<ref name="IWpatents">{{cite news |url=http://www.informationweek.com/news/showArticle.jhtml?articleID=201807587&cid=nl_IWK_daily |title=Google's Secret Patent Portfolio Predicts gPhone |accessdate=2007-11-06 |last=Claburn |first=Thomas |date=2007-09-19 |work=[[InformationWeek]]}}</ref><ref name="MNpatents">{{cite web |url=http://www.moconews.net/entry/419-googles-strong-mobile-related-patent-portfolio/ |title=Google's Strong Mobile-Related Patent Portfolio |accessdate=2007-11-07 |last=Pearce |first=James Quintana |date=2007-09-20 |work=mocoNews.net}}</ref>
+
 
+
===Open Handset Alliance===
+
{{Main|Open Handset Alliance}}
+
{{quote box|width=22.6em|align=right|quote="Today's announcement is more ambitious than any single 'Google Phone' that the press has been speculating about over the past few weeks. Our vision is that the powerful platform we're unveiling will power thousands of different phone models."|source=[[Eric Schmidt]], ''Google Chairman/CEO''<ref name="AndroidAnnouncement"/>}}
+
 
+
On 5 November 2007, the [[Open Handset Alliance]], a [[consortium]] of several companies which include [[Texas Instruments]], [[Broadcom Corporation]], [[Google]], [[High Tech Computer Corporation|HTC]], [[Intel Corporation|Intel]], [[LG Group|LG]], [[Marvell Technology Group]], [[Motorola]], [[Nvidia]], [[Qualcomm]], [[Samsung Electronics]], [[Sprint Nextel]] and [[T-Mobile]] was unveiled with the goal to develop [[open standard]]s for mobile devices.<ref name="AndroidAnnouncement"/> Along with the formation of the Open Handset Alliance, the OHA also unveiled their first product, Android, a mobile device [[platform (computing)|platform]] built on the [[Linux kernel]] version 2.6.<ref name="AndroidAnnouncement"/>
+
 
+
On 9 December 2008, it was announced that 14 new members would be joining the Android project, including [[PacketVideo]], [[ARM Holdings]], [[Atheros Communications]], [[Asustek|Asustek Computer Inc]], [[Garmin|Garmin Ltd]], [[Softbank]], [[Sony Ericsson]], [[Toshiba|Toshiba Corp]], and [[Vodafone|Vodafone Group Plc]].<ref>{{cite web |url=http://www.reuters.com/article/newsOne/idUSN0928595620081210 |title=CORRECTED&nbsp;— UPDATE 2-More mobile phone makers back Google's Android |last=Martinez |first=Jennifer |work=[[Reuters]] |publisher=[[Thomson Reuters]] |date=2008-12-10 |accessdate=2008-12-13}}</ref><ref>{{cite web |url=http://www.businessweek.com/the_thread/techbeat/archives/2008/12/googles_android_2.html |title=Google's Android Gains More Powerful Followers |last=Kharif |first=Olga |work=[[BusinessWeek]] |publisher=[[McGraw-Hill]] |date=2008-12-09 |accessdate=2008-12-13}}</ref>
+
 
+
===Licensing===
+
With the exception of brief update periods, Android has been available as open source since 21 October 2008. Google opened the entire [[source code]] (including network and telephony stacks<ref>{{cite news | url = http://www.eweek.com/c/a/Mobile-and-Wireless/Google-Open-Sources-Android-on-Eve-of-G1-Launch/ | work = [[eWeek]] | title = Google Open-Sources Android on Eve of G1 Launch | first = Clint | last = Boulton | date = 21 October 2008 | accessdate = 2009-09-03}}</ref>) under an [[Apache License]].<ref>{{cite web | url = http://source.android.com/posts/opensource | title = Android is now available as open source | work = Android Open Source Project | first = Dave | last = Bort | date = 21 October 2008 | accessdate = 2009-09-03}}</ref>
+
  
 +
[edit]Early acquisition by Google
 +
In July 2005, Google acquired Android, Inc., a small startup company based in Palo Alto, California, USA.[17] Android's co-founders who went to work at Google included Andy Rubin (co-founder of Danger),[18] Rich Miner (co-founder of Wildfire Communications, Inc.),[19] Nick Sears (once VP at T-Mobile),[20] and Chris White (headed design and interface development at WebTV).[21] At the time, little was known about the functions of Android, Inc. other than that they made software for mobile phones.[17] This began rumors that Google was planning to enter the mobile phone market.
 +
At Google, the team led by Rubin developed a mobile device platform powered by the Linux kernel which they marketed to handset makers and carriers on the premise of providing a flexible, upgradeable system. It was reported that Google had already lined up a series of hardware component and software partners and signaled to carriers that it was open to various degrees of cooperation on their part.[22][23][24] More speculation that Google would be entering the mobile-phone market came in December 2006.[25] Reports from the BBC and The Wall Street Journal noted that Google wanted its search and applications on mobile phones and it was working hard to deliver that. Print and online media outlets soon reported rumors that Google was developing a Google-branded handset.[26] More speculation followed reporting that as Google was defining technical specifications, it was showing prototypes to cell phone manufacturers and network operators.
 +
In September 2007, InformationWeek covered an Evalueserve study reporting that Google had filed several patent applications in the area of mobile telephony.[27][28]
 +
[edit]Open Handset Alliance
 +
Main article: Open Handset Alliance
 +
"Today's announcement is more ambitious than any single 'Google Phone' that the press has been speculating about over the past few weeks. Our vision is that the powerful platform we're unveiling will power thousands of different phone models."
 +
Eric Schmidt, Google Chairman/CEO[4]
 +
On 5 November 2007, the Open Handset Alliance, a consortium of several companies which include Texas Instruments, Broadcom Corporation, Google, HTC, Intel, LG, Marvell Technology Group, Motorola, Nvidia, Qualcomm, Samsung Electronics, Sprint Nextel and T-Mobile was unveiled with the goal to develop open standards for mobile devices.[4] Along with the formation of the Open Handset Alliance, the OHA also unveiled their first product, Android, a mobile device platform built on the Linux kernel version 2.6.[4]
 +
On 9 December 2008, it was announced that 14 new members would be joining the Android project, including PacketVideo, ARM Holdings, Atheros Communications, Asustek Computer Inc, Garmin Ltd, Softbank, Sony Ericsson, Toshiba Corp, and Vodafone Group Plc.[29][30]
 +
[edit]Licensing
 +
With the exception of brief update periods, Android has been available as open source since 21 October 2008. Google opened the entire source code (including network and telephony stacks[31]) under an Apache License.[32]
 
With the Apache License, vendors can add proprietary extensions without submitting those back to the open source community.
 
With the Apache License, vendors can add proprietary extensions without submitting those back to the open source community.
 
+
[edit]Update history
===Update history===
+
 
+
 
+
 
Android has seen a number of updates since its original release. These updates to the base operating system typically fix bugs and add new features.
 
Android has seen a number of updates since its original release. These updates to the base operating system typically fix bugs and add new features.
 +
1.1
 +
Released 9 February 2009
 +
1.5 (Cupcake)
 +
Based on Linux Kernel 2.6.27 On 30 April 2009, the official 1.5 (Cupcake) update for Android was released.[33][34] There were several new features and UI updates included in the 1.5 update:[35]
 +
Ability to record and watch videos through camcorder mode
 +
Uploading videos to YouTube and pictures to Picasa directly from the phone
 +
A new soft-keyboard with text-prediction
 +
Bluetooth A2DP and AVRCP support
 +
Ability to automatically connect to a Bluetooth headset within a certain distance
 +
New widgets and folders that can populate the Home screens
 +
Animated screen transitions
 +
1.6 (Donut)
 +
Based on Linux Kernel 2.6.29[36] On 15 September 2009, the 1.6 (Donut) SDK was released.[37][38] Included in the update were:[36]
 +
An improved Android Market experience
 +
An integrated camera, camcorder, and gallery interface
 +
Gallery now enables users to select multiple photos for deletion
 +
Updated Voice Search, with faster response and deeper integration with native applications, including the ability to dial contacts
 +
Updated search experience to allow searching bookmarks, history, contacts, and the web from the home screen
 +
Updated technology support for CDMA/EVDO, 802.1x, VPNs, and a text-to-speech engine
 +
Support for WVGA screen resolutions
 +
Speed improvements in searching and camera applications
 +
Gesture framework and GestureBuilder development tool
 +
2.0/2.1 (Eclair)
 +
Based on Linux Kernel 2.6.29[39] On 26 October 2009 the 2.0 (Eclair) SDK was released.[40] Among the changes were:[41]
 +
Optimized hardware speed
 +
Support for more screen sizes and resolutions
 +
Revamped UI
 +
New Browser UI and HTML5 support
 +
New contact lists
 +
Better white-black ratio for backgrounds
 +
Improved Google Maps 3.1.2
 +
Microsoft Exchange support
 +
Built in flash support for Camera
 +
Digital Zoom
 +
MotionEvent class enhanced to track multi-touch events[42]
 +
Improved virtual keyboard
 +
Bluetooth 2.1
 +
Live Wallpapers
 +
The 2.0.1 SDK was released on 3 December 2009.[43]
 +
The 2.1 SDK was released on 12 January 2010.[44]
 +
2.2 (Froyo)[45]
 +
Based on Linux Kernel 2.6.32[46] On 20 May 2010 the 2.2 (Froyo) SDK was released.[2] Changes included:[47]
 +
General Android OS speed, memory, and performance optimizations[48]
 +
Additional application speed improvements courtesy of JIT implementation[49]
 +
Integration of Chrome's V8 JavaScript engine into the Browser application
 +
Increased Microsoft Exchange support (security policies, auto-discovery, GAL look-up, calendar synchronization, remote wipe)
 +
Improved application launcher with shortcuts to Phone and Browser applications
 +
USB tethering and WiFi hotspot functionality
 +
Added an option to disable data access over mobile network
 +
Updated Market application with batch and automatic update features[48]
 +
Quick switching between multiple keyboard languages and their dictionaries
 +
Voice dialing and contact sharing over Bluetooth
 +
Support for numeric and alphanumeric passwords
 +
Support for file upload fields in the Browser application[50]
 +
Support for installing applications to the expandable memory[51]
 +
Adobe Flash 10.1 support[52]
 +
3.0 (Gingerbread)
 +
Based on Linux Kernel 2.6.33 or 34[46] Tentatively scheduled for Q4 2010 launch. Confirmed new features:
 +
Support for WebM video playback[53]
 +
Improved copy–paste functionalities[54]
 +
Unconfirmed new features:
 +
Android Market music store[55]
 +
Media streaming from PC library[55]
 +
Revamped UI[56]
 +
[edit]Features
  
{| class="wikitable" style="margin: 1em auto 1em auto; text-align: left"
 
|- style="text-align: left"
 
! style="width:12%" | 1.1 <br />
 
|Released 9 February 2009
 
|-
 
! 1.5 (Cupcake)<br />Based on Linux Kernel 2.6.27
 
| On 30 April 2009, the official 1.5 (Cupcake) update for Android was released.<ref>{{cite web | url=http://android-developers.blogspot.com/2009/04/android-15-is-here.html | title=Android 1.5 is here! | date=27 April 2009 | work=Android Developers Blog | first=Xavier | last=Ducrohet | accessdate=2009-09-03}}</ref><ref>{{cite news | last=Rob | first=Jackson | title=CONFIRMED: Official Cupcake Update Underway for T-Mobile G1 USA & UK! | date=30 April 2009 | url=http://phandroid.com/2009/04/30/official-cupcake-update-underway-for-t-mobile-g1-usa/ | work=Android Phone Fans | accessdate=2009-09-03}}</ref> There were several new features and UI updates included in the 1.5 update:<ref name="cupcake-highlights">{{cite web | date=April 2009 | url=http://developer.android.com/sdk/android-1.5-highlights.html | title=Android 1.5 Platform Highlights | work=Android Developers | accessdate=2009-09-03}}</ref>
 
* Ability to record and watch videos through camcorder mode
 
* Uploading videos to YouTube and pictures to Picasa directly from the phone
 
* A new soft-keyboard with text-prediction
 
* Bluetooth [[A2DP]] and [[AVRCP]] support
 
* Ability to automatically connect to a Bluetooth headset within a certain distance
 
* New widgets and folders that can populate the Home screens
 
* Animated screen transitions
 
|-
 
! style="width: 8em"| 1.6 (Donut)<br />Based on Linux Kernel 2.6.29<ref name="donut-highlights" />
 
|| On 15 September 2009, the 1.6 (Donut) SDK was released.<ref>{{cite web | url=http://android-developers.blogspot.com/2009/09/android-16-sdk-is-here.html | title=Android 1.6 SDK is here | date=15 September 2009 | work=Android Developers Blog | first=Xavier | last=Ducrohet | accessdate=2009-10-01}}</ref><ref>{{cite news | last=Ryan | first=Paul | title=Google releases Android 1.6; Palm unleashes WebOS 1.2 | date=1 October 2009 | url=http://arstechnica.com/gadgets/news/2009/10/google-releases-android-16-palm-releases-webos-12.ars | work=Ars Technica | accessdate=2009-10-01}}</ref> Included in the update were:<ref name="donut-highlights">{{cite web | date=September 2009 | url=http://developer.android.com/sdk/android-1.6-highlights.html | title=Android 1.6 Platform Highlights | work=Android Developers | accessdate=2009-10-01}}</ref>
 
* An improved Android Market experience
 
* An integrated camera, camcorder, and gallery interface
 
* Gallery now enables users to select multiple photos for deletion
 
* Updated Voice Search, with faster response and deeper integration with native applications, including the ability to dial contacts
 
* Updated search experience to allow searching bookmarks, history, contacts, and the web from the home screen
 
* Updated technology support for [[code division multiple access|CDMA]]/[[Evolution-Data Optimized|EVDO]], [[IEEE 802.1X|802.1x]], [[virtual private network|VPN]]s, and a [[speech synthesis|text-to-speech]] engine
 
* Support for [[Wide VGA|WVGA]] screen resolutions
 
* Speed improvements in searching and camera applications
 
* Gesture framework and GestureBuilder development tool
 
|-
 
! 2.0/2.1 (Eclair)<br />Based on Linux Kernel 2.6.29<ref>{{cite web | url = http://www.google.com/phone/static/en_US-nexusone_tech_specs.html | title = Android 2.1 / Eclair on Google Nexus One | work = Android Developers | accessdate = 5 January 2010}} (Eclair)</ref>
 
|| On 26 October 2009 the 2.0 (Eclair) SDK was released.<ref>{{cite web | url = http://developer.android.com/sdk/android-2.0.html | title = Android 2.0, Release 1 | work = Android Developers | accessdate = 27 October 2009}}</ref> Among the changes were:<ref name="eclair-highlights">{{cite web | url = http://developer.android.com/sdk/android-2.0-highlights.html | title = Android 2.0 Platform Highlights | work = Android Developers | accessdate = 27 October 2009}}</ref>
 
* Optimized hardware speed
 
* Support for more screen sizes and resolutions
 
* Revamped UI
 
* New Browser UI and [[HTML5]] support
 
* New contact lists
 
* Better white-black ratio for backgrounds
 
* Improved Google Maps 3.1.2
 
* [[Microsoft Exchange]] support
 
* Built in flash support for Camera
 
* Digital Zoom
 
* MotionEvent class enhanced to track multi-touch events<ref>{{cite web|title=Android 2.0 API Changes Summary|url=http://developer.android.com/sdk/android-2.0.html#api-changes|accessdate=2010-03-06}}</ref>
 
* Improved virtual keyboard
 
* Bluetooth 2.1
 
* Live Wallpapers
 
 
The 2.0.1 SDK was released on 3 December 2009.<ref>{{cite web | url = http://developer.android.com/sdk/android-2.0.1.html | title = Android 2.0.1, Release 1 | work = Android Developers | accessdate = 17 January 2010}}</ref>
 
 
The 2.1 SDK was released on 12 January 2010.<ref>{{cite web | url = http://developer.android.com/sdk/android-2.1.html | title = Android 2.1, Release 1 | work = Android Developers | accessdate = 17 January 2010}}</ref>
 
|-
 
! style="background:#EEDC82" | '''2.2 (Froyo)<ref>{{cite web | date=16 January 2010 | url=http://www.engadget.com/2010/01/16/next-android-version-will-be-called-froyo-says-erick-tseng/ | title=Next Android version will be called Froyo, says Erick Tseng | work=Engadget.com | first=Vladislav | last=Savov | accessdate=2010-01-16}}</ref><br />Based on Linux Kernel 2.6.32<ref name="Swetland">{{cite web | date=7 February 2010 | url=http://lwn.net/Articles/373374/ | title=Some clarification on "the Android Kernel" | work=lwn.net | first=Brian | last=Swetland | accessdate=2010-02-21}}</ref>'''
 
|| On 20 May 2010 the 2.2 (Froyo) SDK was released.<ref name="froyo-goodies"/> Changes included:<ref name="froyo-highlights">{{cite web | date=20 May 2010 | url=http://developer.android.com/sdk/android-2.2-highlights.html | title=Android 2.2 Platform Highlights | work=Android Developers | accessdate=2010-05-23}}</ref>
 
* General Android OS speed, memory, and performance optimizations<ref name="unofficial-froyo-features">{{cite web | url =http://www.androidpolice.com/2010/05/20/exclusive-unofficially-confirmed-froyo-features-post-day-1-of-google-io-google-io-blitz-coverage-day-1/ | title = Unofficially Confirmed Froyo Features, Post-Day-1 Of Google I/O | work = Android Police | accessdate = 20 May 2010}}</ref>
 
* Additional application speed improvements courtesy of [[Just-in-time compilation|JIT]] implementation<ref>{{cite web | url = http://www.androidpolice.com/2010/05/11/exclusive-androidpolice-coms-nexus-one-is-running-android-2-2-froyo-how-fast-is-it-compared-to-2-1-oh-only-about-450-faster/ | title = Nexus One Is Running Android 2.2 Froyo. How Fast Is It Compared To 2.1? Oh, Only About 450% Faster | work = androidpolice | accessdate = 13 May 2010}}</ref>
 
* Integration of [[Google Chrome|Chrome]]'s [[V8 (JavaScript engine)|V8 JavaScript engine]] into the Browser application
 
* Increased Microsoft Exchange support (security policies, auto-discovery, GAL look-up, calendar synchronization, remote wipe)
 
* Improved application launcher with shortcuts to Phone and Browser applications
 
* USB tethering and WiFi hotspot functionality
 
* Added an option to disable data access over mobile network
 
* Updated Market application with batch and automatic update features<ref name="unofficial-froyo-features"/>
 
* Quick switching between multiple keyboard languages and their dictionaries
 
* Voice dialing and contact sharing over Bluetooth
 
* Support for numeric and alphanumeric passwords
 
* Support for file upload fields in the Browser application<ref>{{cite web | url = http://code.google.com/p/android/issues/detail?id=2519#c112 | title = Browser support for file upload field is coming in Froyo | work = Google Code | accessdate = 13 May 2010}}</ref>
 
* Support for installing applications to the expandable memory<ref>{{cite web | url = http://code.google.com/p/android/issues/detail?id=1151#c535 | title = Android support for memory card app storage is finally "coming soon" | work = Google Code | accessdate = 1 May 2010}}</ref>
 
* [[Adobe Flash]] 10.1 support<ref>{{cite web | url = http://bits.blogs.nytimes.com/2010/04/27/googles-andy-rubin-on-everything-android/ | title = Google's Andy Rubin on Everything Android | work = NY Times | accessdate = 20 May 2010}}</ref>
 
|-
 
! 3.0 (Gingerbread)<br />Based on Linux Kernel 2.6.33 or 34<ref name="Swetland"/>
 
|| Tentatively scheduled for Q4 2010 launch. Confirmed new features:
 
* Support for [[WebM]] video playback<ref>{{cite web | url=http://www.webmproject.org/about/faq/#webm_video_file_format | title=When will other Google products support WebM and VP8? | work=The WebM Project | accessdate=20 May 2010}}</ref>
 
* Improved [[Cut, copy, and paste|copy–paste]] functionalities<ref>{{cite web | url = http://code.google.com/p/android/issues/detail?id=3190#c81 | title = Issue 3190: Improve copy-paste in Browser/WebView | work = Google Code | accessdate = 20 May 2010}}</ref>
 
Unconfirmed new features: 
 
* Android Market music store<ref name="Android Music">{{cite web |url = http://www.pcworld.com/article/196871/android_music_store_to_take_on_apple_itunes.html |title = Android Music Store to Take on Apple iTunes}}</ref>
 
* Media streaming from PC library<ref name="Android Music"/>
 
* Revamped UI<ref>{{cite web | url = http://techcrunch.com/2010/06/16/android-team-laser-focused-on-the-user-experience-for-next-release/ | title = Android Team “Laser Focused” On The User Experience For Next Release}}</ref>
 
|-
 
|}
 
 
==Features==
 
[[Image:Android home.png|thumb|The Android Emulator default home screen (v1.5).]]
 
Current features and specifications:<ref name="WhatIsAndroid">{{cite web |url=http://developer.android.com/guide/basics/what-is-android.html |title=What is Android? |date=21 July 2009 |work=Android Developers |accessdate=2009-09-03}}</ref><ref name="EnSDK">{{cite news |url=http://www.engadget.com/2007/11/12/googles-android-os-early-look-sdk-now-available/ |title=Google's Android OS early look SDK now available |accessdate=2007-11-12 |last=Topolsky |first=Joshua |date=2007-11-12 |work=[[Engadget]]}}</ref><ref name="mediaformats">{{cite web |url=http://developer.android.com/guide/appendix/media-formats.html |title=Android Supported Media Formats |work=Android Developers |accessdate=2009-05-01}}</ref>
 
 
{| class="wikitable" style="margin: 1em auto 1em auto; text-align: left"
 
|- style="text-align: left"
 
! Handset layouts
 
|| The platform is adaptable to larger, [[Video Graphics Array|VGA]], [[2D computer graphics|2D graphics]] library, [[3D computer graphics|3D graphics]] library based on [[OpenGL ES]] 2.0 specifications, and traditional smartphone layouts.
 
|-
 
! Storage
 
| [[SQLite]], a lightweight [[relational database]], is used for data storage purposes
 
|-
 
! Connectivity
 
|| Android supports connectivity technologies including [[GSM]]/[[Enhanced Data Rates for GSM Evolution|EDGE]], [[Integrated Digital Enhanced Network|IDEN]], [[Code division multiple access|CDMA]], [[Evolution-Data Optimized|EV-DO]], [[Universal Mobile Telecommunications System|UMTS]], [[Bluetooth]], [[Wi-Fi]], and [[WiMAX]].
 
|-
 
! Messaging
 
|| [[SMS]] and [[Multimedia Messaging Service|MMS]] are available forms of messaging, including threaded [[text messaging]] and now Android Cloud to Device Messaging Framework(C2DM) is also a part of Android Push Messaging service.
 
|-
 
! Web browser
 
|| The web browser available in Android is based on the open-source [[WebKit]] layout engine, coupled with [[Google Chrome|Chrome]]'s [[V8 (JavaScript engine)|V8]] JavaScript engine. The browser scores a 93/100 on the [[Acid3]] Test.
 
|-
 
! Java support
 
|| While Android applications are written in [[Java (programming language)|Java]], there's no [[Java Virtual Machine]] in the platform and Java byte code is not executed. Java classes get recompiled into [[Dalvik executable]] and run on [[Dalvik virtual machine]]. Dalvik is a specialized virtual machine designed specifically for Android and optimized for battery-powered mobile devices with limited memory and CPU. Android does not support [[J2ME]], like some other mobile operating systems.
 
|-
 
! Media support
 
|| Android supports the following audio/video/still media formats: [[H.263]], [[H.264]] (in [[3GP]] or [[MP4]] [[container format (digital)|container]]), [[MPEG-4 Part 2|MPEG-4 SP]], [[Adaptive multi-rate compression|AMR]], [[AMR-WB]] (in 3GP container), [[Advanced Audio Coding|AAC]], [[HE-AAC]] (in MP4 or 3GP container), [[MP3]], [[Musical Instrument Digital Interface|MIDI]], [[Vorbis|Ogg Vorbis]], [[WAV]], [[JPEG]], [[Portable Network Graphics|PNG]], [[Graphics Interchange Format|GIF]], [[BMP]].<ref name="mediaformats" />
 
|-
 
! Additional hardware support
 
|| Android can use video/still cameras, [[touchscreen]]s, [[Global Positioning System|GPS]], [[accelerometer]]s, [[magnetometer]]s, accelerated 2D [[bit blit]]s (with hardware orientation, scaling, pixel format conversion) and accelerated 3D graphics.
 
|-
 
! Development environment
 
|| Includes a device emulator, tools for [[debugging]], memory and [[Software performance analysis|performance profiling]], and a [[plugin]] for the [[Eclipse (software)|Eclipse IDE]].
 
|-
 
! Market
 
|| Like many phone-based application stores, the [[Android Market]] is a catalog of applications that can be downloaded and installed to target hardware over-the-air, without the use of a PC. Originally only free applications were supported. Paid-for applications have been available on the Android Market in the United States since 19 February 2009.<ref>{{cite web|url=http://www.engadget.com/2009/02/19/paid-apps-appear-in-android-market/|title=Paid apps appear in Android Market|work=[[Engadget]]|first=Nilay|last=Patel|date=19 February 2009|accessdate=2009-04-06}}</ref> The Android Market has been expanding rapidly. As of April 30, 2010, it had over 50,000 Android applications for download.<ref>{{cite web |http://www.androidcentral.com/android-market-now-has-38000-apps |title= Android Market now has 50,000 Apps| first = Phil | last = Nickinson | date=30 April 2010 |publisher=''[[AndroidCentral]]'' |accessdate=30 April 2010}}</ref>
 
|-
 
! Multi-touch
 
|| Android has native support for [[multi-touch]] which was initially made available in handsets such as the [[HTC Hero]]. The feature was originally disabled at the kernel level (possibly to avoid infringing Apple's patents on touch-screen technology).<ref>{{cite news | url = http://news.cnet.com/8301-13579_3-10161312-37.html | work = [[CNET News]] | title = Report: Apple nixed Android's multitouch | date = 11 February 2009 | first = Steven | last = Musil | accessdate = 2009-09-03}}</ref> Google has since released an update for the [[Nexus One]] and the [[Motorola Droid]] which enables multi-touch natively.<ref>{{cite web | http://www.engadget.com/2010/02/02/nexus-one-gets-a-software-update-enables-multitouch/ | title = Nexus One gets a software update, enables multitouch | work = [[Engadget]] | first = Chris | last = Ziegler | date = 2 February 2010 | accessdate = 2 February 2010}}</ref>
 
|-
 
! Bluetooth
 
|| Support for [[A2DP]] and [[AVRCP]] were added in version 1.5;<ref name="cupcake-highlights"/> sending files (OPP) and accessing the phone book (PBAP) were added in version 2.0;<ref name="eclair-highlights"/> and voice dialing and sending contacts between phones were added in version 2.2.<ref name="froyo-highlights"/>
 
|-
 
! Videocalling
 
|| Not supported by default but as seen with the [[HTC Evo 4G]], handset manufacturers can build front-facing cameras into their phones, so Qik, a software from the Android Market can use it for video-calling. {{Citation needed|date=April 2010}}
 
|-
 
! Multitasking
 
|| Multitasking of applications is available.<ref>{{cite web | url = http://android-developers.blogspot.com/2010/04/multitasking-android-way.html | title = Multitasking the Android Way | accessdate = 2010-05-17 | last = Bray | first = Tim | date = 2010-04-28 | work = Android Developers}}</ref>
 
|-
 
|}
 
 
[[File:Diagram android.png|thumb|left|Architecture Diagram]]
 
 
==Hardware running Android==
 
{{Main|List of Android devices}}
 
The first phone to run the Android operating system was the [[HTC Dream]], released on 22 October 2008.<ref name=HTC>{{cite news|publisher=HTC|url=http://www.htc.com/www/press.aspx?id=66338&lang=1033|accessdate=2009-05-19|title=T-Mobile Unveils the T-Mobile G1 - the First Phone Powered by Android}} AT&T's first  device to run the Android OS was the Motorola Backflip.</ref>
 
 
==Software development==
 
[[Image:Android mobile phone platform early device.jpg|thumb|200px|Early Android device.]]
 
The early feedback on developing applications for the Android platform was mixed.<ref name="MixedFeedback">{{cite web |url=http://arstechnica.com/news.ars/post/20071219-google-android-plagued-by-dysfunctional-development-process.html |title=Developing apps for Google Android: it's a mixed bag |accessdate=2007-12-19 |last=Paul |first=Ryan |date=2007-12-19 |work=[[Ars Technica]]}}</ref> Issues cited include bugs, lack of documentation, inadequate QA infrastructure, and no public issue-tracking system. (Google announced an issue tracker on 18 January 2008.)<ref>{{cite web |url=http://android-developers.blogspot.com/2008/01/you-cant-rush-perfection-but-now-you.html |title=You can't rush perfection, but now you can file bugs against it |work=Android Developers Blog |first=Dan |last=Morrill |date=18 January 2008 |accessdate=2009-09-03}}</ref> In December 2007, MergeLab mobile startup founder Adam MacBeth stated, ''"Functionality is not there, is poorly documented or just doesn't work... It's clearly not ready for prime time."''<ref name="Bugs">{{cite web |url=http://online.wsj.com/article_email/SB119800856883537515-lMyQjAxMDE3OTE4ODAxMDg4Wj.html |title=Glitches Bug Google's Android Software |accessdate=2007-12-19 |last=Morrison |first=Scott |date=2007-12-19 |work=The Wall Street Journal |publisher= }}</ref> Despite this, Android-targeted applications began to appear the week after the platform was announced. The first publicly available application was the [[Snake (video game)|Snake game]].<ref>{{cite web |url=http://www.android-freeware.org/download/snake |title=Snake |accessdate=2008-01-26 |work=Android Freeware Directory}}</ref><ref name="Snake">{{cite web |url=http://www.mobiles2day.com/2007/11/14/first-android-application-snake/ |title=First Android Application&nbsp;— Snake |accessdate=2008-01-07 |date=2007-11-14 |work=Mobiles2day |publisher= }}</ref>
 
The [[Android Dev Phone]] is a [[Subscriber Identity Module|SIM]]-unlocked and hardware-unlocked device that is designed for advanced developers. While developers can use regular consumer devices purchased at retail to test and use their applications, some developers may choose not to use a retail device, preferring an unlocked or no-contract device.
 
 
===Software development kit===
 
The Android SDK includes a comprehensive set of development tools.<ref>{{cite web | url = http://developer.android.com/guide/developing/tools/index.html | title = Tools Overview | work = Android Developers | date = 21 July 2009}}</ref> These include a [[debugger]], [[Software library|libraries]], a handset [[emulator]] (based on [[QEMU]]), documentation, sample code, and tutorials. Currently supported development platforms include [[x86]]-architecture computers running [[Linux kernel|Linux]] (any modern desktop [[List of Linux distributions|Linux distribution]]), [[Mac OS X]] 10.4.8 or later, [[Windows XP]] or [[Windows Vista|Vista]]. Requirements also include [[Java Development Kit]], [[Apache Ant]], and [[Python (programming language)|Python]] 2.2 or later. The officially supported [[integrated development environment]] (IDE) is [[Eclipse (software)|Eclipse]] (3.2 or later) using the Android Development Tools (ADT) Plugin, though developers may use any text editor to edit Java and XML files then use [[command line]] tools to create, build and debug Android applications as well as control attached Android devices (e.g., triggering a reboot, installing software package(s) remotely).<ref>{{cite web |url = http://jonwestfall.com/2009/08/backup-restore-android-apps-using-adb/ | title = Backup & Restore Android Apps Using ADB | first = Jon | last = Westfall | date = 25 August 2009 | work = JonWestfall.com | accessdate = 7 December 2009}}</ref>
 
 
A preview release of the Android [[software development kit]] (SDK) was released on 12 November 2007. On 15 July 2008, the Android Developer Challenge Team accidentally sent an email to all entrants in the Android Developer Challenge announcing that a new release of the SDK was available in a "private" download area. The email was intended for winners of the first round of the Android Developer Challenge. The revelation that Google was supplying new SDK releases to some developers and not others (and keeping this arrangement private) has led to widely reported frustration within the Android developer community.<ref>{{cite web |url=http://www.theregister.co.uk/2008/07/14/android_developer_unrest/ |title=Google plays Hide and Seek with Android SDK |first=Cade |last=Metz |date=14 July 2008 |accessdate=2008-10-23 |work=[[The Register]]}}</ref>
 
 
On 18 August 2008 the Android 0.9 SDK beta was released. This release provided an updated and extended API, improved development tools and an updated design for the home screen. Detailed instructions for upgrading are available to those already working with an earlier release.<ref>{{cite web |url=http://code.google.com/android/intro/upgrading.html |title=Android&nbsp;— An Open Handset Alliance Project: Upgrading the SDK |accessdate=2008-10-24}}{{Dead link|date=September 2009}}</ref> On 23 September 2008 the Android 1.0 SDK (Release 1) was released.<ref>{{cite web |url=http://developer.android.com/sdk/older_releases.html |title=Other SDK Releases |accessdate=2009-09-02 |work=Android Developers}}</ref> According to the release notes, it included "mainly bug fixes, although some smaller features were added". It also included several API changes from the 0.9 version.
 
 
On 9 March 2009, Google released version 1.1 for the Android dev phone. While there are a few aesthetic updates, a few crucial updates include support for "search by voice, priced applications, alarm clock fixes, sending gmail freeze fix, fixes mail notifications and refreshing intervals, and now the maps show business reviews". Another important update is that Dev phones can now access paid applications and developers can now see them on the Android Market.<ref>{{cite web |url=http://phandroid.com/2009/03/09/android-dev-phone-update-version-11/ |title=Android Dev Phone Update: Version 1.1! |first=Rob |last=Jackson |date=9 March 2009 |accessdate=2009-09-03 |work=Android Phone Fans}}</ref>
 
 
In the middle of May 2009, Google released version 1.5 (Cupcake) of the Android OS and SDK.  This update included many new features including video recording, support for the stereo bluetooth profile, a customizable onscreen keyboard system and voice recognition.  This release also opened up the AppWidget framework to third party developers allowing anyone to create their own home screen widgets.<ref>{{cite web |url=http://developer.android.com/sdk/android-1.5.html#features |title=Android 1.5 Version Notes |work=Android Developers |month=April |year=2009 |accessdate=2009-09-03}}</ref>
 
 
In September 2009 the "Donut" version (1.6) was released which featured better search, battery usage indicator and VPN control applet. New platform technologies included Text to Speech engine (not available on all phones), Gestures & Accessibility framework.<ref>{{cite web |url=http://developer.android.com/sdk/android-1.6-highlights.html |title=Android 1.6 Version Notes |work=Android Developers |month=September |year=2009 |accessdate=2009-09-03}}</ref>
 
 
Android Applications are packaged in [[APK (file format)|.apk]] format and stored under <code>/data/app</code> folder on the Android OS. The user can run the command <code>adb root</code> to access this folder as only the root has permissions to access this folder.
 
 
===App Inventor for Android===
 
On July 12, 2010 Google announced the availability of App Inventor for Android, a Web-based visual development environment for novice programmers, based on MIT's Open Blocks Java library and providing access to Android devices' GPS, accelerometer and orientation data, phone functions, text messaging, speech-to-text conversion, contact data, persistent storage, and Web services, initially including Amazon and Twitter. <ref>{{cite news|last=Claburn|first=Thomas|title=Google App Inventor Simplifies Android Programming |url=http://www.informationweek.com/news/smb/mobile/showArticle.jhtml?articleID=225702880&subSection=News|accessdate=2010-07-12|newspaper=Information Week|date=2010-07-12}}</ref>  "We could only have done this because Android’s architecture is so open," said the project director, MIT's [[Hal Abelson]].<ref>{{cite news|last=Lohr|first=Steve|title=Google’s Do-It-Yourself App Creation Software|url=http://www.nytimes.com/2010/07/12/technology/12google.html?src=busln|accessdate=2010-07-12|newspaper=New York Times|date=2010-07-11}}</ref>  Under development for over a year<ref>{{cite news|last=Abelson|first=Hal|title=App Inventor for Android|url=http://googleresearch.blogspot.com/2009/07/app-inventor-for-android.html|accessdate=2010-07-12|newspaper=Google Research Blog|date=2009-07-31}}</ref>, the block-editing tool has been taught to non-majors in computer science at Harvard, MIT, Wellsley, and the University of San Francisco, where professor David Wolber developed an introductory computer science course and tutorial book for non-computer science students based on App Inventor for Android.<ref>{{cite news|last=Kim|first=Ryan|title=Google brings app-making to the masses|url=http://articles.sfgate.com/2009-12-11/business/17220628_1_computer-science-smart-phone-android|accessdate=2010-07-12|newspaper=San Francisco Chronicle|date=2009-12-11}}</ref><ref>{{cite web|last=Wolber|first=David|title=AppInventor.org|url=http://www.appinventor.org/|accessdate=2010-07-12}}</ref>
 
 
===Android Developer Challenge===
 
The [[Android Developer Challenge]] was a competition for the most innovative application for Android. Google offered prizes totaling 10 million [[US dollar]]s, distributed between ADC I and ADC II. ADC I accepted submissions from 2 January to 14 April 2008. The 50 most promising entries, announced on 12 May 2008, each received a $25,000 award to fund further development.<ref>{{cite web | url = http://android-developers.blogspot.com/2008/05/top-50-applications.html | work = Android Developers Blog | title = The Top 50 Applications | first = Jason | last = Chen | date = 12 May 2008 | accessdate = 2009-09-04}}</ref><ref>{{cite news | url = http://www.linuxdevices.com/news/NS3168326017.html | title = Android Developer Challenge announces first-round winners | work = Linux for Devices | first = Eric | last = Brown | date = 13 May 2008}}</ref> It ended in early September with the announcement of ten teams that received $275,000 each, and ten teams that received $100,000 each.<ref name=ADC>{{cite web|url=http://code.google.com/android/adc/adc_gallery/|title=ADC I Top 50 Gallery|accessdate=2009-05-19|work=Android Developer Challenge}}</ref> ADC II was announced on 27 May 2009.<ref name="Challenge">{{cite web |url=http://code.google.com/android/adc/ |title=Android Developer Challenge |accessdate=2008-01-11 |work=Google Code}}</ref> The first round of the ADC II closed on 6 October 2009.<ref>{{cite web | url = http://android-developers.blogspot.com/2009/10/adc-2-round-1-scoring-complete.html | title = ADC 2 Round 1 Scoring Complete | work = Android Developers Blog | first = Eric | last = Chu | date = 6 October 2009 | accessdate = 3 November 2009}}</ref> The first-round winners of ADC II comprising the top 200 applications were announced on 5 November 2009. Voting for the second round also opened on the same day and ended on November 25. Google announced the top winners of ADC II on November 30, with SweetDreams, What the Doodle!? and [[WaveSecure]] being nominated the overall winners of the challenge.<ref>{{cite web | url = http://code.google.com/android/adc/gallery_winners.html | title = ADC 2 Overall Winners | work = Android Developer Challenge | publisher = Google | accessdate = 5 December 2010}}</ref><ref>{{cite web | url = http://www.businessweek.com/the_thread/techbeat/archives/2009/11/android_develop_2.html | title = Android Developer Challenge 2 Winners Announced | work = BusinessWeek | first = Olga | last = Kharif | date = 30 November 2009 | accessdate = 5 December 2010}}</ref>
 
 
===Google applications===
 
Google has also participated in the Android Market by offering several applications for its services. These applications include [[Google Voice]] for the Google Voice service, Sky Map for watching stars, Finance for their finance service, Maps Editor for their MyMaps service, Places Directory for their Local Search, [[Google Goggles]] that searches by image, Google Translate, Google Shopper, Listen for podcasts and My Tracks, a jogging application.
 
 
===Third party applications===
 
With the growing number of Android handsets, there has also been an increased interest by third party developers to port their applications to the Android operating system. Famous applications that have been converted to the Android operating system include [[Shazam (service)|Shazam]], Backgrounds, and [[WeatherBug]].
 
 
The Android operating system has also been considered important enough{{weasel-inline}} by a lot of the most popular internet sites and services to create native applications. These include [[MySpace]], [[Facebook]], and [[Twitter]].
 
 
As of 15th July 2010, the Android Marketplace had over 70,000 applications, with over 1 billion downloads.<ref>{{cite web |url=http://www.engadget.com/2010/07/15/android-market-now-has-100-000-apps-passes-1-billion-download-m/ |title=Android Market Has 100,000 Apps & Passes 1 Billion Downloads |date=2009-07-15 |accessdate=2009-07-15}}</ref><ref>{{cite web |url=http://www.fonehome.co.uk/2010/07/16/android-market-hits-1-billion-downloads-100000-apps/ |title=Android Market Htis 1 Billion Downloads & 100,000 apps |date=2009-07-15 |accessdate=2009-07-15}}</ref>
 
 
===Native code===
 
Libraries written in [[C (programming language)|C]] and other languages can be compiled to [[ARM architecture|ARM]] [[native code]] and installed using the Android Native Development Kit.  Native classes can be called from Java code running under the Dalvik VM using the <code>System.loadLibrary</code> call, which is part of the standard Android Java classes.<ref>{{cite web |url=http://davanum.wordpress.com/2007/12/09/android-invoke-jni-based-methods-bridging-cc-and-java/ |title=Android&nbsp;— Invoke JNI based methods (Bridging C/C++ and Java) |last=Srinivas |first=Davanum |date=2007-12-09 |accessdate=2008-12-13}}</ref><ref>{{cite web |url=http://developer.android.com/reference/java/lang/System.html |title=java.lang.System |work=Android Developers |accessdate=2009-09-03}}</ref>
 
 
Complete applications can be compiled and installed using traditional development tools.<ref name="benno">{{cite web|url=http://benno.id.au/blog/2007/11/13/android-native-apps|title=Native C application for Android|date=13 November 2007|work=Benno's blog|first=Ben|last=Leslie|accessdate=2009-09-04}}</ref>  The ADB debugger gives a root shell under the Android Emulator which allows native [[ARM architecture|ARM code]] to be uploaded and executed. ARM code can be compiled using [[GNU Compiler Collection|GCC]] on a standard PC.<ref name="benno"/> Running native code is complicated by the fact that Android uses a non-standard C library (known as Bionic). The underlying graphics device is available as a [[framebuffer]] at ''/dev/graphics/fb0''.<ref>{{cite mailing list |url=http://groups.google.com/group/android-developers/msg/ace258af92fff692?dmode=source&pli=1 |title=Native C *GRAPHICAL* applications now working on Android emulator |last=Cooksey |first=Tom |mailinglist=android-developers |date=2007-11-07 |accessdate=2008-12-13}}</ref> The graphics library that Android uses to arbitrate and control access to this device is called the [[Skia Graphics Engine|Skia Graphics Library]] (SGL), and it has been released under an open source license.<ref>{{cite web|url=http://src.chromium.org/viewvc/chrome/trunk/src/skia/|title=Skia source}}</ref> Skia has backends for both [[win32]] and [[Unix]], allowing the development of cross-platform applications, and it is the graphics engine underlying the [[Google Chrome]] web browser.<ref>{{cite web |url=http://www.atoker.com/blog/2008/09/06/skia-graphics-library-in-chrome-first-impressions/ |title=Skia graphics library in Chrome: First impressions |last=Toker |first=Alp |date=2008-09-06 |accessdate=2008-12-13}}</ref>
 
 
===Community-based firmware===
 
There is a community of open-source enthusiasts that build and share Android-based firmware with a number of customizations and additional features, such as [[FLAC]] lossless audio support and the ability to store downloaded applications on the [[microSD]] card.<ref>{{cite web |url=http://forum.xda-developers.com/forumdisplay.php?f=448 |work=xda-developers forum |title=Dream android development |accessdate=2009-09-11}}</ref> This usually involves [[Rooting (Android OS)|rooting]] the device. Rooting lets users load modified firmwares allowing users of  older phones to use applications available only on newer releases.<ref>{{cite web | url=http://voltmobileandtech.com/blog/| title= Android 2.1 from Motorola Droid Ported to G1| work=[[Volt Mobile]] | date= march 10, 2010}}</ref>
 
 
Those firmware packages are updated frequently, incorporate elements of Android functionality that haven't yet been officially released within a carrier-sanctioned firmware, and tend to have fewer limitations. [[CyanogenMod]] is one such firmware.
 
 
On 24 September 2009, Google issued a cease and desist letter<ref>{{cite web | url = http://androidandme.com/2009/09/hacks/cyanogenmod-in-trouble/ | title = CyanogenMod in trouble? | work = Android and me | first = Taylor | last = Wimberly | date = 24 September 2009 | accessdate = 26 September 2009}}</ref> to the modder Cyanogen, citing issues with the re-distribution of Google's closed-source applications<ref>{{cite web | url = http://android-developers.blogspot.com/2009/09/note-on-google-apps-for-android.html | title = A Note on Google Apps for Android | work = Android Developers Blog | first = Dan | last = Morrill | date = 25 September 2009 | accessdate = 26 September 2009}}</ref> within the custom firmware. Even though Android OS is open source, phones come packaged with closed-source Google applications for functionality such as the application store and GPS navigation.  Google has asserted that these applications can only be provided through approved distribution channels by licensed distributors.  Cyanogen has complied with Google's wishes and is continuing to distribute this mod without the proprietary software.  He has provided a method to back up licensed Google applications during the mod's install process and restore them when it is complete.<ref>{{cite web | url = http://www.cyanogenmod.com/home/the-current-state | title = The current state... | work = CyanogenMod Android Rom | first = Cyanogen | date = 27 September 2009 | accessdate = 27 September 2009}}</ref>
 
 
==Marketing==
 
[[File:Android-logo.jpg|thumb|Android robot logo.]]
 
===Logos===
 
Android uses the [[Droid (font)|Droid font family]] made by [[Ascender Corporation]].<ref>{{cite news | url = http://www.forbes.com/2008/09/25/font-android-g1-tech-wire-cx_ew_0926font.html | title = Android's Very Own Font | work = [[Forbes]] | first = Elizabeth | last = Woyke | date = 26 September 2008 }}</ref>
 
 
Android Green is the color of the Android Robot that represents the Android operating system. The print color is PMS 376C and the online hex color is #A4C639, as specified by the Android Brand Guidelines.<ref>{{cite web | url = http://www.android.com/branding.html | work = Android | title = Brand Guidelines | date = 23 March 2009 | accessdate = 30 October 2009}}</ref>
 
 
===Typeface===
 
[[Image:Android.svg|thumb|right|Text logo.]]
 
 
The custom typeface of Android is called Norad, only used in the text logo.<ref>{{cite web | url = http://www.android.com/branding.html | work = Android | title = Android Brand Guidelines | date = 23 March 2009 | accessdate = 10 April 2010}}</ref>
 
 
===Market share===
 
Research company [[Canalys]] estimates that by Q2 2009,  Android had a 2.8% share of the worldwide [[smartphone]] market.<ref name=Insider_1>{{cite news |title=Canalys: iPhone outsold all Windows Mobile phones in Q2 2009 |url=http://www.appleinsider.com/articles/09/08/21/canalys_iphone_outsold_all_windows_mobile_phones_in_q2_2009.html |newspaper=[[AppleInsider]] |date=21 August 2009 |accessdate=21 September 2009}}</ref> By the following quarter (Q3 2009), Android's market share had grown to 3.5%.<ref>{{cite news |title=Canalys Q3 2009: iPhone, RIM taking over smartphone market |url=http://www.appleinsider.com/articles/09/11/03/canalys_q3_2009_iphone_rim_taking_over_smartphone_market.html |newspaper=[[AppleInsider]] |date=3 November 2009 |accessdate=3 November 2009}}</ref>
 
  
In February 2010 [[ComScore]] ranked the Android platform as obtaining a 9.0% of the smartphone platform marketshare. This figure was up from an earlier estimate of 5.2% stated in November 2009.<ref name="ComScore Feb 2010">{{cite news |title=Top smarthphone platforms, 3 mos. ending 2/10 |author=Staff writer |first= |last= |authorlink= |url=http://www.mycomscore.net/Press_Events/Press_Releases/2010/4/comScore_Reports_February_2010_U.S._Mobile_Subscriber_Market_Share |format= |agency=comScore MobiLens |newspaper=[[Bloomberg Television]] |publisher= |location= |isbn= |issn= |oclc= |pmid= |pmd= |bibcode= |doi= |id= |date=April 2010 |page= |pages= |at= |accessdate=April 19, 2010 |trans_title= |quote=RIM, 42.1%; Apple, 25.4%; Microsoft, 15.1%; Google (Android), 9.0%; Palm, 5.4%; others, 3.0%  |archiveurl= |archivedate= |ref= }}</ref> In July 2010 [[ComScore]] revised Android's share for 3 months March/April/May 2010 to 13.0%, an increase of 4 percentage points, 0.2 percentage points behind Microsoft whose share had dropped 1.9%.<ref>http://www.comscore.com/Press_Events/Press_Releases/2010/7/comScore_Reports_May_2010_U.S._Mobile_Subscriber_Market_Share</ref>
 
  
In October 2009, [[Gartner|Gartner Inc.]] predicted that by 2012, Android would become the world's second most popular smartphone platform, behind [[Nokia]]'s [[Symbian OS]], which is very popular outside the US. Meanwhile, [[BlackBerry]] would fall from 2nd to 5th place, [[iPhone]] would remain in 3rd place, and Microsoft's [[Windows Mobile]] would remain in 4th<!--  See article referenced. --> place.<ref>{{Cite news |title=Android to grab No. 2 spot by 2012, says Gartner |newspaper=[[ComputerWorld]] |date=6 October 2009 |url=http://www.computerworld.com/s/article/9139026/Android_to_grab_No._2_spot_by_2012_says_Gartner }}</ref>
+
The Android Emulator default home screen (v1.5).
 +
Current features and specifications:[57][58][59]
 +
Handset layouts The platform is adaptable to larger, VGA, 2D graphics library, 3D graphics library based on OpenGL ES 2.0 specifications, and traditional smartphone layouts.
 +
Storage SQLite, a lightweight relational database, is used for data storage purposes
 +
Connectivity Android supports connectivity technologies including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi, and WiMAX.
 +
Messaging SMS and MMS are available forms of messaging, including threaded text messaging and now Android Cloud to Device Messaging Framework(C2DM) is also a part of Android Push Messaging service.
 +
Web browser The web browser available in Android is based on the open-source WebKit layout engine, coupled with Chrome's V8 JavaScript engine. The browser scores a 93/100 on the Acid3 Test.
 +
Java support While Android applications are written in Java, there's no Java Virtual Machine in the platform and Java byte code is not executed. Java classes get recompiled into Dalvik executable and run on Dalvik virtual machine. Dalvik is a specialized virtual machine designed specifically for Android and optimized for battery-powered mobile devices with limited memory and CPU. Android does not support J2ME, like some other mobile operating systems.
 +
Media support Android supports the following audio/video/still media formats: H.263, H.264 (in 3GP or MP4 container), MPEG-4 SP, AMR, AMR-WB (in 3GP container), AAC, HE-AAC (in MP4 or 3GP container), MP3, MIDI, Ogg Vorbis, WAV, JPEG, PNG, GIF, BMP.[59]
 +
Additional hardware support Android can use video/still cameras, touchscreens, GPS, accelerometers, magnetometers, accelerated 2D bit blits (with hardware orientation, scaling, pixel format conversion) and accelerated 3D graphics.
 +
Development environment Includes a device emulator, tools for debugging, memory and performance profiling, and a plugin for the Eclipse IDE.
 +
Market Like many phone-based application stores, the Android Market is a catalog of applications that can be downloaded and installed to target hardware over-the-air, without the use of a PC. Originally only free applications were supported. Paid-for applications have been available on the Android Market in the United States since 19 February 2009.[60] The Android Market has been expanding rapidly. As of April 30, 2010, it had over 50,000 Android applications for download.[61]
 +
Multi-touch Android has native support for multi-touch which was initially made available in handsets such as the HTC Hero. The feature was originally disabled at the kernel level (possibly to avoid infringing Apple's patents on touch-screen technology).[62] Google has since released an update for the Nexus One and the Motorola Droid which enables multi-touch natively.[63]
 +
Bluetooth Support for A2DP and AVRCP were added in version 1.5;[35] sending files (OPP) and accessing the phone book (PBAP) were added in version 2.0;[41] and voice dialing and sending contacts between phones were added in version 2.2.[47]
 +
Videocalling Not supported by default but as seen with the HTC Evo 4G, handset manufacturers can build front-facing cameras into their phones, so Qik, a software from the Android Market can use it for video-calling.[citation needed]
 +
Multitasking Multitasking of applications is available.[64]
  
Analytics firm Flurry estimates that 250,000 [[Motorola Droid]] phones were sold in the United States during the phone's first week in stores.<ref>{{cite news |title=Droid Sales and the Android Explosion |newspaper=[[PC World (magazine)|PC World]] |date=17 November 2009 |url=http://www.pcworld.com/article/182310/droid_sales_and_the_android_explosion.html }}</ref>
 
  
In May 2010, Android's first quarter US sales surpassed that of the rival iPhone platform.  According to a report by the NPD group, Android achieved 28% smartphone sales in the US market, up 8% from the December quarter.  The iPhone's sales were flat at 21% over the same reporting period.<ref>{{cite news|title=Android's Market Share Surpasses iPhone's, NPD Says|newspaper=[[MarketWatch]]|date=10 May 2010|url=http://www.marketwatch.com/story/android-market-share-passes-iphones-npd-data-2010-05-10}}</ref>
+
Architecture Diagram
 +
[edit]Hardware running Android
  
According to an interview with Eric Schmidt in ''The Guardian'', Android is getting 160,000 new users per day (end June 2010) up from 100,000 per day in May 2010.<ref>{{cite web|last=Arthur|first=Charles|title=Eric Schmidt's dog whistle to mobile developers: abandon Windows Phone|publisher=[[The Guardian]]|url=http://www.guardian.co.uk/technology/2010/jun/25/android-schmidt-mobile-platform|date=2010-06-25}}</ref>
+
Main article: List of Android devices
 +
The first phone to run the Android operating system was the HTC Dream, released on 22 October 2008.[65]
 +
[edit]Software development
  
==Restrictions and issues==
 
Unlike closed-source mobile platforms like [[Apple Inc.|Apple's]] [[iOS (Apple)|iOS]], Google tracks issues and feature requests publicly at [[Google Code]]'s site.<ref>{{cite web | url = http://code.google.com/p/android/issues/list | title = Issues - android | work = [[Google Code]] | accessdate = 15 January 2010}}</ref>
 
  
===Linux compatibility===
 
* Android's kernel was derived from [[Linux]] but has been tweaked by Google outside the main [[Linux kernel]] tree.<ref>{{cite video |url=http://www.youtube.com/watch?v=QBGfUs9mQYY |title= Androidology - Part 1 of 3 - Architecture Overview |date=2008-09-06 |accessdate=2007-11-07 |medium=Video |publisher=[[YouTube]]}}</ref>  Android does not have a native [[X Window System]] nor does it support the full set of standard [[GNU]] libraries and this makes it difficult to port existing GNU/Linux applications or libraries to Android.<ref>{{cite web
 
| url=http://arstechnica.com/open-source/reviews/2009/02/an-introduction-to-google-android-for-developers.ars
 
| title=Dream(sheep++): A developer's introduction to Google Android
 
| date=23 February 2009
 
| last=Paul|first=Ryan
 
| work=[[Ars Technica]]
 
| quote=In fact, during a presentation at the Google IO conference, Google engineer Patrick Brady stated unambiguously that Android is not Linux. (...) The problem with Google's approach is that it makes Android an island. The highly insular nature of the platform prevents Android users and developers from taking advantage of the rich ecosystem of existing third-party Linux applications. Android doesn't officially support native C programs at all, so it won't be possible to port your favorite GTK+ or Qt applications to Android
 
| accessdate=2009-03-07}}</ref>
 
* Google no longer maintains the code they previously contributed to the [[Linux kernel]] as part of their Android effort, effectively [[Branching (software)|branching]] kernel code in their own tree, separating their code from Linux.<ref name="hartmann">{{cite web | url = http://www.kroah.com/log/linux/android-kernel-problems.html | title = Android and the Linux kernel community | date = 2010-02-02 | author=[[Greg Kroah-Hartman]] | quote=''This means that any drivers written for Android hardware platforms, can not get merged into the main kernel tree because they have dependencies on code that only lives in Google's kernel tree, causing it to fail to build in the kernel.org tree. Because of this, Google has now prevented a large chunk of hardware drivers and platform code from ever getting merged into the main kernel tree. Effectively creating a kernel branch that a number of different vendors are now relying on.(...) But now they are stuck. Companies with Android-specific platform and drivers can not contribute upstream, which causes these companies a much larger maintenance and development cycle.'' | accessdate = 2010-02-03}}</ref><ref name="hartmann2">{{cite web | url = http://news.zdnet.com/2100-9595_22-389733.html | title = Linux developer explains Android kernel code removal | date = 2010-02-02 | publisher=[[ZDNet]] | accessdate = 2010-02-03}}</ref><ref>{{cite web |url=http://developer.android.com/guide/basics/what-is-android.html |title=What is Android? |work=Android Developers | accessdate=8 January 2010}}</ref> The code which is no longer maintained was deleted in January 2010 from the Linux [[codebase]].<ref>{{cite web
 
| url=http://www.h-online.com/open/features/Android-versus-Linux-924563.html
 
| title=Android versus Linux?
 
| date=9 February 2010
 
| work=www.h-online.com
 
| accessdate=2010-02-28}}</ref> However, Google announced in April 2010 that they will employ staff to work with the Linux kernel community.<ref>{{cite web | url=http://blogs.zdnet.com/open-source/?p=6274 | title=DiBona: Google will hire two Android coders to work with kernel.org | date=15 April 2010 | work=www.zdnet.com | accessdate=2010-04-29}}</ref>
 
  
===Networking issues===
+
Early Android device.
*Android did not support setting up a [[proxy server|network proxy]] configuration for WiFi connections until Android 2.1 (Eclair).<ref>[http://code.google.com/p/android/issues/detail?id=1273&colspec=ID%20Type%20Status%20Owner%20Summary%20Stars Issue 1273], first reported 12 November 2008, unreviewed as of June 2010.</ref>
+
The early feedback on developing applications for the Android platform was mixed.[66] Issues cited include bugs, lack of documentation, inadequate QA infrastructure, and no public issue-tracking system. (Google announced an issue tracker on 18 January 2008.)[67] In December 2007, MergeLab mobile startup founder Adam MacBeth stated, "Functionality is not there, is poorly documented or just doesn't work... It's clearly not ready for prime time."[68] Despite this, Android-targeted applications began to appear the week after the platform was announced. The first publicly available application was the Snake game.[69][70] The Android Dev Phone is a SIM-unlocked and hardware-unlocked device that is designed for advanced developers. While developers can use regular consumer devices purchased at retail to test and use their applications, some developers may choose not to use a retail device, preferring an unlocked or no-contract device.
*Android does not support [[Wi-Fi Protected Access#EAP extensions under WPA- and WPA2- Enterprise|EAP extensions under WPA- and WPA2- Enterprise]].<ref>[http://code.google.com/p/android/issues/detail?id=1386&colspec=ID%20Type%20Status%20Owner%20Summary%20Stars Issue 1386], first reported 28 November 2008, unreviewed as of June 2010.</ref>
+
[edit]Software development kit
*Android does not support [[Cisco ASA|Cisco]]-compatible [[IPsec]] [[virtual private network]]s ([[Layer 2 Tunneling Protocol]] is supported).<ref>[http://code.google.com/p/android/issues/detail?id=3902&colspec=ID%20Type%20Status%20Owner%20Summary%20Stars Issue 3902], first reported 15 September 2009, unreviewed as of June 2010.</ref>
+
The Android SDK includes a comprehensive set of development tools.[71] These include a debugger, libraries, a handset emulator (based on QEMU), documentation, sample code, and tutorials. Currently supported development platforms include x86-architecture computers running Linux (any modern desktop Linux distribution), Mac OS X 10.4.8 or later, Windows XP or Vista. Requirements also include Java Development Kit, Apache Ant, and Python 2.2 or later. The officially supported integrated development environment (IDE) is Eclipse (3.2 or later) using the Android Development Tools (ADT) Plugin, though developers may use any text editor to edit Java and XML files then use command line tools to create, build and debug Android applications as well as control attached Android devices (e.g., triggering a reboot, installing software package(s) remotely).[72]
*Android did not support [[wireless ad hoc network]]ing until Android 2.2 (Froyo).<ref>[http://code.google.com/p/android/issues/detail?id=82&colspec=ID%20Type%20Status%20Owner%20Summary%20Stars Issue 82], first reported 24 January 2008, given status "reviewed" on 25 January 2008.</ref>
+
A preview release of the Android software development kit (SDK) was released on 12 November 2007. On 15 July 2008, the Android Developer Challenge Team accidentally sent an email to all entrants in the Android Developer Challenge announcing that a new release of the SDK was available in a "private" download area. The email was intended for winners of the first round of the Android Developer Challenge. The revelation that Google was supplying new SDK releases to some developers and not others (and keeping this arrangement private) has led to widely reported frustration within the Android developer community.[73]
 +
On 18 August 2008 the Android 0.9 SDK beta was released. This release provided an updated and extended API, improved development tools and an updated design for the home screen. Detailed instructions for upgrading are available to those already working with an earlier release.[74] On 23 September 2008 the Android 1.0 SDK (Release 1) was released.[75] According to the release notes, it included "mainly bug fixes, although some smaller features were added". It also included several API changes from the 0.9 version.
 +
On 9 March 2009, Google released version 1.1 for the Android dev phone. While there are a few aesthetic updates, a few crucial updates include support for "search by voice, priced applications, alarm clock fixes, sending gmail freeze fix, fixes mail notifications and refreshing intervals, and now the maps show business reviews". Another important update is that Dev phones can now access paid applications and developers can now see them on the Android Market.[76]
 +
In the middle of May 2009, Google released version 1.5 (Cupcake) of the Android OS and SDK. This update included many new features including video recording, support for the stereo bluetooth profile, a customizable onscreen keyboard system and voice recognition. This release also opened up the AppWidget framework to third party developers allowing anyone to create their own home screen widgets.[77]
 +
In September 2009 the "Donut" version (1.6) was released which featured better search, battery usage indicator and VPN control applet. New platform technologies included Text to Speech engine (not available on all phones), Gestures & Accessibility framework.[78]
 +
Android Applications are packaged in .apk format and stored under /data/app folder on the Android OS. The user can run the command adb root to access this folder as only the root has permissions to access this folder.
 +
[edit]App Inventor for Android
 +
On July 12, 2010 Google announced the availability of App Inventor for Android, a Web-based visual development environment for novice programmers, based on MIT's Open Blocks Java library and providing access to Android devices' GPS, accelerometer and orientation data, phone functions, text messaging, speech-to-text conversion, contact data, persistent storage, and Web services, initially including Amazon and Twitter. [79] "We could only have done this because Android’s architecture is so open," said the project director, MIT's Hal Abelson.[80] Under development for over a year[81], the block-editing tool has been taught to non-majors in computer science at Harvard, MIT, Wellsley, and the University of San Francisco, where professor David Wolber developed an introductory computer science course and tutorial book for non-computer science students based on App Inventor for Android.[82][83]
 +
[edit]Android Developer Challenge
 +
The Android Developer Challenge was a competition for the most innovative application for Android. Google offered prizes totaling 10 million US dollars, distributed between ADC I and ADC II. ADC I accepted submissions from 2 January to 14 April 2008. The 50 most promising entries, announced on 12 May 2008, each received a $25,000 award to fund further development.[84][85] It ended in early September with the announcement of ten teams that received $275,000 each, and ten teams that received $100,000 each.[86] ADC II was announced on 27 May 2009.[87] The first round of the ADC II closed on 6 October 2009.[88] The first-round winners of ADC II comprising the top 200 applications were announced on 5 November 2009. Voting for the second round also opened on the same day and ended on November 25. Google announced the top winners of ADC II on November 30, with SweetDreams, What the Doodle!? and WaveSecure being nominated the overall winners of the challenge.[89][90]
 +
[edit]Google applications
 +
Google has also participated in the Android Market by offering several applications for its services. These applications include Google Voice for the Google Voice service, Sky Map for watching stars, Finance for their finance service, Maps Editor for their MyMaps service, Places Directory for their Local Search, Google Goggles that searches by image, Google Translate, Google Shopper, Listen for podcasts and My Tracks, a jogging application.
 +
[edit]Third party applications
 +
With the growing number of Android handsets, there has also been an increased interest by third party developers to port their applications to the Android operating system. Famous applications that have been converted to the Android operating system include Shazam, Backgrounds, and WeatherBug.
 +
The Android operating system has also been considered important enough[weasel words] by a lot of the most popular internet sites and services to create native applications. These include MySpace, Facebook, and Twitter.
 +
As of 15th July 2010, the Android Marketplace had over 70,000 applications, with over 1 billion downloads.[91][92]
 +
[edit]Native code
 +
Libraries written in C and other languages can be compiled to ARM native code and installed using the Android Native Development Kit. Native classes can be called from Java code running under the Dalvik VM using the System.loadLibrary call, which is part of the standard Android Java classes.[93][94]
 +
Complete applications can be compiled and installed using traditional development tools.[95] The ADB debugger gives a root shell under the Android Emulator which allows native ARM code to be uploaded and executed. ARM code can be compiled using GCC on a standard PC.[95] Running native code is complicated by the fact that Android uses a non-standard C library (known as Bionic). The underlying graphics device is available as a framebuffer at /dev/graphics/fb0.[96] The graphics library that Android uses to arbitrate and control access to this device is called the Skia Graphics Library (SGL), and it has been released under an open source license.[97] Skia has backends for both win32 and Unix, allowing the development of cross-platform applications, and it is the graphics engine underlying the Google Chrome web browser.[98]
 +
[edit]Community-based firmware
 +
There is a community of open-source enthusiasts that build and share Android-based firmware with a number of customizations and additional features, such as FLAC lossless audio support and the ability to store downloaded applications on the microSD card.[99] This usually involves rooting the device. Rooting lets users load modified firmwares allowing users of older phones to use applications available only on newer releases.[100]
 +
Those firmware packages are updated frequently, incorporate elements of Android functionality that haven't yet been officially released within a carrier-sanctioned firmware, and tend to have fewer limitations. CyanogenMod is one such firmware.
 +
On 24 September 2009, Google issued a cease and desist letter[101] to the modder Cyanogen, citing issues with the re-distribution of Google's closed-source applications[102] within the custom firmware. Even though Android OS is open source, phones come packaged with closed-source Google applications for functionality such as the application store and GPS navigation. Google has asserted that these applications can only be provided through approved distribution channels by licensed distributors. Cyanogen has complied with Google's wishes and is continuing to distribute this mod without the proprietary software. He has provided a method to back up licensed Google applications during the mod's install process and restore them when it is complete.[103]
 +
[edit]Marketing
  
===Issues concerning application development===
 
* Android does not use established Java standards, i.e. [[Java SE]] and [[Java ME|ME]]. This prevents compatibility among Java applications written for those platforms and those for the Android platform. Android only reuses the Java language syntax, but does not provide the full-class libraries and APIs bundled with Java SE or ME.<ref>{{cite web
 
| url=http://www.javalobby.org/nl/archive/jlnews_20071113o.html
 
| title=Google Android: Initial Impressions and Criticism
 
| date=13 November 2007
 
| last=van Gurp|first=Jilles
 
| work=Javalobby
 
| quote=''Frankly, I don't understand why Google intends to ignore the vast amount of existing implementation out there. It seems like a bad case of "not invented here" to me. Ultimately, this will slow adoption. There are already too many Java platforms for the mobile world and this is yet another one''
 
| accessdate=2009-03-07}}</ref> However, the [[Myriad Group]] claim that their new J2Android tool can convert Java MIDlets into Android applications.<ref>{{cite web
 
| url=http://www.myriadgroup.com/Media-Centre/News/Myriad-New-J2Android-Converter-Fuels-Android-Applications-Gold-Rush.aspx
 
| title=Myriad's New J2Android Converter Fuels Android Applications Gold Rush
 
| date=19 March 2010}}</ref><ref>{{cite web
 
| url=http://www.javaworld.com/community/node/4170
 
| title=J2Android hopes you don't know that Android is Java-based
 
| quote=''On the other hand, you might think this is kind of a scam aimed at developers who don't really understand the nature of the platform they're targeting. My biggest complaint is that you'd think that Mikael Ricknäs, the IDG News Service reporter who wrote the first story linked to above (who toils for the same company that publishes JavaWorld), would have at least mentioned the relationship between Java and Android to make the oddness of this announcement clear.''
 
| date=23 March 2010}}</ref><ref>{{cite web
 
| url=http://www.javaworld.com/community/?q=node/4210
 
| title=Myriad CTO: J2Android moves MIDlets to "beautiful" Android framework
 
| quote=''We will have to wait and see exactly how much pickup J2Android actually sees. The tool isn't actually available on the open market just yet; while Schillings spoke optimistically about "converting 1,000 MIDlets in an afternoon," at the moment they're working with a few providers to transform their back catalogs. So those of you out there hoping to avoid learning how to write Android code may have to wait a while.''
 
| date=31 March 2010}}</ref>
 
* Developers have reported that it is difficult to maintain applications on multiple versions of Android, owing to compatibility issues between versions 1.5 and 1.6,<ref>{{cite web | url = http://developer.htc.com/adp.html | title = HTC Developer center: Android Dev Phone 1 | publisher=[[HTC Corporation]] | quote=''For development, you should select the lowest possible Android platform version that meets the needs of your applications. For example, if you are working in the Android 1.1 SDK and your application is using APIs introduced in Android 1.1, then you should download the Android 1.1 system image. If you are using the Android 1.1 SDK but your application does not use Android 1.1 APIs, then using Android 1.0 image is sufficient. For testing, consider downloading all platform versions with which your application is compatible, then running your applications on those platform versions to ensure that they work as designed.'' | accessdate = 2010-01-15}}</ref><ref>{{cite web | url = http://blogs.zdnet.com/Greenfield/?p=481 | title = Android's Weakest Link | publisher=[[ZDNet]] | date = 2009-10-11 | accessdate = 2010-01-15}}</ref> especially the different resolution ratios in use among various Android phones.<ref>{{cite web | url = http://androidandme.com/2009/11/news/complications-looming-for-android-developers/ | title = Complications looming for Android developers | publisher=androidandme.com | date = 2009-11-06 | accessdate = 2010-01-15}}</ref> Such problems were poignantly brought into focus as they were encountered during the ADC2 contest.<ref>{{cite web | url = http://www.techcrunch.com/2009/10/11/a-chink-in-androids-armor/ | title = A Chink In Android's Armor | date = 2009-10-11 | publisher=[[TechCrunch]] | quote=''And now they're faced with a landslide of new handsets, some running v.1.6 and some courageous souls even running android v.2.0. All those manufacturers/carriers are racing to release their phones by the 2009 holiday season, and want to ensure the hot applications will work on their phones. And here's the problem&nbsp;– in almost every case, we hear, there are bugs and more serious problems with the apps.[...]First of all, the compatibility between versions issue may be overblown. The reported problems have been limited to an Android developer contest[...]We haven’t heard of any major app developers complaining of backwards or forward compatibility problems. Also, I’ve now upgraded my phone from 1.5 to 1.6, and every application continues to work fine.'' | accessdate = 2009-10-11}}</ref>
 
* The rapid growth in the number of Android-based phone models with differing hardware capabilities also makes it difficult to develop applications that work on all Android-based phones.<ref>{{cite web | url = http://www.wired.com/gadgetlab/2009/11/android-fragmentation/ | title = Android’s Rapid Growth Has Some Developers Worried | date = 2009-11-16 | publisher=[[Wired News]] | quote=''Fagan’s concerns about the fragmentation of Android is being echoed by other developers, says Sean Galligan, vice president of business development at Flurry, an mobile app analytics company(...)"You may build an app that works perfectly with all three firmwares, but then when you run it on carriers’ ROMs it completely blows up," says Fagan. "So we find ourselves having to create apps that are compatible with multiple firmwares, multiple ROMs and multiple devices with different hardware.'' | accessdate = 2010-02-26}}</ref><ref>{{cite web | url = http://www.javaworld.com/community/node/3704 | title = Android just reproducing Java ME's problems, now | date = 2009-11-17 | publisher=[[JavaWorld]] | accessdate = 2010-02-26}}</ref><ref>{{cite web | url = http://www.businessweek.com/technology/content/oct2009/tc20091015_626136.htm | title = Android's Spread Could Become a Problem | date = 2009-10-15 | publisher=[[Bloomberg BusinessWeek|BusinessWeek]] | accessdate = 2010-02-28}}</ref><ref>{{cite web | url = http://infoworld.com/d/mobilize/google-androids-self-destruction-derby-begins-863 | title = Google Android's self-destruction derby begins | date = 2010-02-22 | publisher=[[InfoWorld]] | accessdate = 2010-02-28}}</ref> As of June 2010, 50% of Android phones run the 2.1 version, and 24.6% still run the 1.5 version<ref>{{cite web | url = http://developer.android.com/resources/dashboard/platform-versions.html | title = Platform Versions | date = 2010-05-03 | publisher=developer.android.com | accessdate = 2010-06-27}}</ref>
 
* Older versions of Android do not readily support [[Bluetooth]] file exchange,<ref>{{cite web | url = http://code.google.com/p/android/issues/detail?id=719 | title = Issue 719 - android - enhanced low-level Bluetooth support | work = [[Google Code]] | accessdate = 19 February 2010}}</ref> although it may still be achieved with some hacking.<ref>{{cite web | url = http://i-miss-erin.blogspot.com/2010_02_01_archive.html | title = Reading, Writing and Arithmetic | first = Erin | last = Yueh | accessdate = 16 February 2010}}</ref> Bluetooth is supported by more recent phones.<ref>{{cite web | url = http://blog.brightpointuk.co.uk/transferring-files-htc-desire-and-htc-legend-bluetooth | title = Transferring files to the HTC Desire and HTC Legend via Bluetooth | first =  | last =  | accessdate = 20 June 2010}}</ref>
 
* Android does not support [[video call]]s as do other mobile operating systems, such as [[Symbian OS]] and [[Windows Mobile]], although third-party, applications like [[Qik]] allow video calling on some models, and video broadcasting on others.<ref>{{cite web | url = http://articles.sfgate.com/2010-06-04/business/21656741_1_video-chat-video-phone-qik | title = Sprint to offer Qik video chat on smart phones | first = Ryan | last = Kim | accessdate = 19 June 2010}}</ref>
 
  
=== Time zones ===
 
Using the native [[Google Calendar]] functionality for Android phones, an Android device user runs into the same limitations that exist in the Calendar application. The most noticeable defect is the lack of proper [[time zone]] support: it is not possible to set the time zone for start/end times of events.<ref>[http://getsatisfaction.com/google/topics/google_calendar_needs_per_event_timezone_support Community-powered support for Google]</ref><ref>[http://www.androidguys.com/2010/01/21/fixit-google-calendar-time-zones/ Android Guys, Fix Google Calendar!]</ref><ref>[http://www.washingtonpost.com/wp-dyn/content/article/2010/04/03/AR2010040304956.html Washington Post, Google Calendar's time zone weakness]</ref> Because of this issue, users experience difficulty while traveling with Android devices.<ref>http://code.google.com/p/android/issues/detail?id=5892 Android Code issue 5892</ref>
 
  
==See also==
+
Android robot logo.
{{Columns-list|colwidth=20em|
+
[edit]Logos
*[[List of Android OS-related topics]]
+
Android uses the Droid font family made by Ascender Corporation.[104]
*[[Android Market]]
+
Android Green is the color of the Android Robot that represents the Android operating system. The print color is PMS 376C and the online hex color is #A4C639, as specified by the Android Brand Guidelines.[105]
*[[BlackBerry OS]]
+
[edit]Typeface
*[[Dalvik virtual machine]]
+
*[[Google Chrome OS]]
+
*[[iOS (Apple)|iOS]]
+
*[[LiMo Foundation]]
+
*[[Linux Phone Standards Forum]]
+
*[[List of Android devices]]
+
*[[List of Open Source Android Applications]]
+
*[[Maemo]]
+
*[[MeeGo]]
+
*[[Nexus One]]
+
*[[Goobuntu]]
+
*[[Samsung]]'s [[bada (operating system)|Bada OS]]
+
*[[Mobile World Congress]]
+
*[[Mobilinux]]
+
*[[Moblin project]]
+
*[[OPhone]]
+
*[[Open Mobile Alliance]]
+
*[[Openmoko]]
+
*[[Palm, Inc.]]'s [[webOS]]
+
*[[Symbian Foundation]]
+
*[[Windows Mobile]]
+
*[[Windows Phone 7]]
+
*[[Google TV]]
+
*[[Motorola Droid|Droid]] (from [[Motorola]])
+
*[[Triad Method]]
+
}}
+
  
==References==
 
{{Reflist|colwidth=30em}}
 
  
==Bibliography==
+
Text logo.
{{Refbegin}}
+
The custom typeface of Android is called Norad, only used in the text logo.[106]
* {{cite book
+
[edit]Market share
| first1      = Burnette
+
Research company Canalys estimates that by Q2 2009, Android had a 2.8% share of the worldwide smartphone market.[107] By the following quarter (Q3 2009), Android's market share had grown to 3.5%.[108]
| last1      = Ed
+
In February 2010 ComScore ranked the Android platform as obtaining a 9.0% of the smartphone platform marketshare. This figure was up from an earlier estimate of 5.2% stated in November 2009.[109] In July 2010 ComScore revised Android's share for 3 months March/April/May 2010 to 13.0%, an increase of 4 percentage points, 0.2 percentage points behind Microsoft whose share had dropped 1.9%.[110]
| date        = November 10, 2009
+
In October 2009, Gartner Inc. predicted that by 2012, Android would become the world's second most popular smartphone platform, behind Nokia's Symbian OS, which is very popular outside the US. Meanwhile, BlackBerry would fall from 2nd to 5th place, iPhone would remain in 3rd place, and Microsoft's Windows Mobile would remain in 4th place.[111]
| title      = Hello, Android: Introducing Google's Mobile Development Platform
+
Analytics firm Flurry estimates that 250,000 Motorola Droid phones were sold in the United States during the phone's first week in stores.[112]
| publisher  = [[Pragmatic Bookshelf]]
+
In May 2010, Android's first quarter US sales surpassed that of the rival iPhone platform. According to a report by the NPD group, Android achieved 28% smartphone sales in the US market, up 8% from the December quarter. The iPhone's sales were flat at 21% over the same reporting period.[113]
| edition    = 2nd
+
According to an interview with Eric Schmidt in The Guardian, Android is getting 160,000 new users per day (end June 2010) up from 100,000 per day in May 2010.[114]
| isbn        = 1934356492
+
[edit]Restrictions and issues
| url        = http://pragprog.com/titles/eband2/hello-android
+
}}
+
* {{cite book
+
| first1      = Rick
+
| last1      = Rogers
+
| first2      = John
+
| last2      = Lombardo
+
| first3      = Zigurd
+
| last3      = Mednieks
+
| first4      = Blake
+
| last4      = Meike
+
| date        = May 1, 2009
+
| title      = Android Application Development: Programming with the Google SDK
+
| publisher  = [[O'Reilly Media]]
+
| edition    = 1st
+
| isbn        = 0596521472
+
| url        = http://oreilly.com/catalog/9780596521509
+
}}
+
* {{cite book
+
| first1      = Frank
+
| last1      = Ableson
+
| first2      = Charlie
+
| last2      = Collins
+
| first3      = Robi
+
| last3      = Sen
+
| date        = May 1, 2009
+
| title      = Unlocking Android: A Developer's Guide
+
| publisher  = [[Manning]]
+
| edition    = 1st
+
| isbn        = 1933988673
+
| url        = http://www.manning.com/ableson/
+
}}
+
* {{cite book
+
| first1      = Shane
+
| last1      = Conder
+
| first2      = Lauren
+
| last2      = Darcey
+
| date        = September 7, 2009
+
| title      = Android Wireless Application Development
+
| publisher  = [[Addison-Wesley Professional]]
+
| edition    = 1st
+
| isbn        = 0321627091
+
| url        = http://www.informit.com/store/product.aspx?isbn=0321627091
+
}}
+
* {{cite book
+
| first1      = Mark
+
| last1      = Murphy
+
| date        = June 26, 2009
+
| title      = Beginning Android
+
| publisher  = [[Apress]]
+
| edition    = 1st
+
| isbn        = 1430224193
+
| url        = http://www.apress.com/book/view/1430224193
+
}}
+
* {{cite book
+
| first1      = Sayed Y.
+
| last1      = Hashimi
+
| first2      = Satya
+
| last2      = Komatineni
+
| first3      = Dave
+
| last3      = MacLean
+
| date        = February 26, 2010
+
| title      = Pro Android 2
+
| publisher  = [[Apress]]
+
| edition    = 2nd
+
| isbn        = 1430226595
+
| url        = http://www.apress.com/book/view/1430226595
+
}}
+
* {{cite book
+
| first1      = Reto
+
| last1      = Meier
+
| date        = November 24, 2008
+
| title      = Professional Android Application Development
+
| publisher  = [[Wrox Press]]
+
| edition    = 1st
+
| isbn        = 0470344717
+
| url        = http://www.wrox.com/WileyCDA/WroxTitle/Professional-Android-Application-Development.productCd-0470344717.html
+
}}
+
* {{cite book
+
| first      = Jerome
+
| last        = DiMarzio
+
| date        = July 30, 2008
+
| title      = ANDROID A PROGRAMMERS GUIDE
+
| publisher  = [[McGraw-Hill|McGraw-Hill Osborne Media]]
+
| edition    = 1st
+
| isbn        = 0071599886
+
| url        = http://www.mhprofessional.com/product.php?isbn=0071599886&cat=112
+
}}
+
* {{cite book
+
| first      = Chris
+
| last        = Haseman
+
| date        = July 21, 2008
+
| title      = Android Essentials
+
| publisher  = [[Apress]]
+
| edition    = 1st
+
| isbn        = 1430210648
+
| url        = http://www.apress.com/book/view/1430210648
+
}}
+
{{Refend}}
+
  
==External links==
+
Unlike closed-source mobile platforms like Apple's iOS, Google tracks issues and feature requests publicly at Google Code's site.[115]
{{Wikinews|Google Android smartphone sales triple in the UK this year}}
+
[edit]Linux compatibility
{{Commonscat|Android (operating system)}}
+
Android's kernel was derived from Linux but has been tweaked by Google outside the main Linux kernel tree.[116] Android does not have a native X Window System nor does it support the full set of standard GNU libraries and this makes it difficult to port existing GNU/Linux applications or libraries to Android.[117]
*[http://www.android.com/ Official Android page]
+
Google no longer maintains the code they previously contributed to the Linux kernel as part of their Android effort, effectively branching kernel code in their own tree, separating their code from Linux.[118][119][120] The code which is no longer maintained was deleted in January 2010 from the Linux codebase.[121] However, Google announced in April 2010 that they will employ staff to work with the Linux kernel community.[122]
**[http://source.android.com/ Android Open Source Project]
+
[edit]Networking issues
**[http://www.android.com/market Android Market]
+
Android did not support setting up a network proxy configuration for WiFi connections until Android 2.1 (Eclair).[123]
**[http://developer.android.com/ Android Developers]
+
Android does not support EAP extensions under WPA- and WPA2- Enterprise.[124]
**[http://android-developers.blogspot.com/ Android Developers Blog]
+
Android does not support Cisco-compatible IPsec virtual private networks (Layer 2 Tunneling Protocol is supported).[125]
**[http://www.android.com/branding/ Android Brand Guidelines]
+
Android did not support wireless ad hoc networking until Android 2.2 (Froyo).[126]
*[http://code.google.com/android Google Projects for Android] from [[Google Code]]
+
[edit]Issues concerning application development
*[http://www.androidwiki.com/ Android Wiki]
+
Android does not use established Java standards, i.e. Java SE and ME. This prevents compatibility among Java applications written for those platforms and those for the Android platform. Android only reuses the Java language syntax, but does not provide the full-class libraries and APIs bundled with Java SE or ME.[127] However, the Myriad Group claim that their new J2Android tool can convert Java MIDlets into Android applications.[128][129][130]
*{{youtube|1FJHYqE0RDg|Sergey Brin introduces the Android platform}}
+
Developers have reported that it is difficult to maintain applications on multiple versions of Android, owing to compatibility issues between versions 1.5 and 1.6,[131][132] especially the different resolution ratios in use among various Android phones.[133] Such problems were poignantly brought into focus as they were encountered during the ADC2 contest.[134]
*{{dmoz|Computers/Systems/Handhelds/Android}}
+
The rapid growth in the number of Android-based phone models with differing hardware capabilities also makes it difficult to develop applications that work on all Android-based phones.[135][136][137][138] As of June 2010, 50% of Android phones run the 2.1 version, and 24.6% still run the 1.5 version[139]
 +
Older versions of Android do not readily support Bluetooth file exchange,[140] although it may still be achieved with some hacking.[141] Bluetooth is supported by more recent phones.[142]
 +
Android does not support video calls as do other mobile operating systems, such as Symbian OS and Windows Mobile, although third-party, applications like Qik allow video calling on some models, and video broadcasting on others.[143]
 +
[edit]Time zones
 +
Using the native Google Calendar functionality for Android phones, an Android device user runs into the same limitations that exist in the Calendar application. The most noticeable defect is the lack of proper time zone support: it is not possible to set the time zone for start/end times of events.[144][145][146] Because of this issue, users experience difficulty while traveling with Android devices.[147]

Revision as of 02:03, 29 July 2010

Android is an operating system for mobile devices such as cellular phones, tablet computers and netbooks. Android was developed by Google and based upon the Linux kernel and GNU software. It was initially developed by Android Inc. (a firm later purchased by Google) and lately by the Open Handset Alliance.[4] According to NPD Group, unit sales for Android OS smartphones ranked second among all smartphone OS handsets sold in the U.S. in the first quarter of 2010.[5][6] BlackBerry OS holds 36% and iOS holds 21% ranked first and third respectively with Android at second with 28%.[7] A Nielsen report for the same quarter placed Android in fourth place with 9% of the market.[8][9] Android has a large community of developers writing apps that extend the functionality of the devices. There are currently over 70,000 apps available for Android, which makes it the second most popular mobile development target.[10] Developers write managed code in the Java language, controlling the device via Google-developed Java libraries.[11] The unveiling of the Android distribution on 5 November 2007 was announced with the founding of the Open Handset Alliance, a consortium of 71 hardware, software, and telecom companies devoted to advancing open standards for mobile devices.[12][13] Google released most of the Android code under the Apache License, a free software and open source license.[14] The Android operating system software stack consists of Java applications running on a Java based object oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore[15] media framework, SQLite relational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc. The Android operating system consists of 12 million lines of code including 3 million lines of XML, 2.8 million lines of C, 2.1 million lines of Java, and 1.75 million lines of C++.[16] Contents [hide] 1 History 1.1 Early acquisition by Google 1.2 Open Handset Alliance 1.3 Licensing 1.4 Update history 2 Features 3 Hardware running Android 4 Software development 4.1 Software development kit 4.2 App Inventor for Android 4.3 Android Developer Challenge 4.4 Google applications 4.5 Third party applications 4.6 Native code 4.7 Community-based firmware 5 Marketing 5.1 Logos 5.2 Typeface 5.3 Market share 6 Restrictions and issues 6.1 Linux compatibility 6.2 Networking issues 6.3 Issues concerning application development 6.4 Time zones 7 See also 8 References 9 Bibliography 10 External links [edit]History

[edit]Early acquisition by Google In July 2005, Google acquired Android, Inc., a small startup company based in Palo Alto, California, USA.[17] Android's co-founders who went to work at Google included Andy Rubin (co-founder of Danger),[18] Rich Miner (co-founder of Wildfire Communications, Inc.),[19] Nick Sears (once VP at T-Mobile),[20] and Chris White (headed design and interface development at WebTV).[21] At the time, little was known about the functions of Android, Inc. other than that they made software for mobile phones.[17] This began rumors that Google was planning to enter the mobile phone market. At Google, the team led by Rubin developed a mobile device platform powered by the Linux kernel which they marketed to handset makers and carriers on the premise of providing a flexible, upgradeable system. It was reported that Google had already lined up a series of hardware component and software partners and signaled to carriers that it was open to various degrees of cooperation on their part.[22][23][24] More speculation that Google would be entering the mobile-phone market came in December 2006.[25] Reports from the BBC and The Wall Street Journal noted that Google wanted its search and applications on mobile phones and it was working hard to deliver that. Print and online media outlets soon reported rumors that Google was developing a Google-branded handset.[26] More speculation followed reporting that as Google was defining technical specifications, it was showing prototypes to cell phone manufacturers and network operators. In September 2007, InformationWeek covered an Evalueserve study reporting that Google had filed several patent applications in the area of mobile telephony.[27][28] [edit]Open Handset Alliance Main article: Open Handset Alliance "Today's announcement is more ambitious than any single 'Google Phone' that the press has been speculating about over the past few weeks. Our vision is that the powerful platform we're unveiling will power thousands of different phone models." Eric Schmidt, Google Chairman/CEO[4] On 5 November 2007, the Open Handset Alliance, a consortium of several companies which include Texas Instruments, Broadcom Corporation, Google, HTC, Intel, LG, Marvell Technology Group, Motorola, Nvidia, Qualcomm, Samsung Electronics, Sprint Nextel and T-Mobile was unveiled with the goal to develop open standards for mobile devices.[4] Along with the formation of the Open Handset Alliance, the OHA also unveiled their first product, Android, a mobile device platform built on the Linux kernel version 2.6.[4] On 9 December 2008, it was announced that 14 new members would be joining the Android project, including PacketVideo, ARM Holdings, Atheros Communications, Asustek Computer Inc, Garmin Ltd, Softbank, Sony Ericsson, Toshiba Corp, and Vodafone Group Plc.[29][30] [edit]Licensing With the exception of brief update periods, Android has been available as open source since 21 October 2008. Google opened the entire source code (including network and telephony stacks[31]) under an Apache License.[32] With the Apache License, vendors can add proprietary extensions without submitting those back to the open source community. [edit]Update history Android has seen a number of updates since its original release. These updates to the base operating system typically fix bugs and add new features. 1.1 Released 9 February 2009 1.5 (Cupcake) Based on Linux Kernel 2.6.27 On 30 April 2009, the official 1.5 (Cupcake) update for Android was released.[33][34] There were several new features and UI updates included in the 1.5 update:[35] Ability to record and watch videos through camcorder mode Uploading videos to YouTube and pictures to Picasa directly from the phone A new soft-keyboard with text-prediction Bluetooth A2DP and AVRCP support Ability to automatically connect to a Bluetooth headset within a certain distance New widgets and folders that can populate the Home screens Animated screen transitions 1.6 (Donut) Based on Linux Kernel 2.6.29[36] On 15 September 2009, the 1.6 (Donut) SDK was released.[37][38] Included in the update were:[36] An improved Android Market experience An integrated camera, camcorder, and gallery interface Gallery now enables users to select multiple photos for deletion Updated Voice Search, with faster response and deeper integration with native applications, including the ability to dial contacts Updated search experience to allow searching bookmarks, history, contacts, and the web from the home screen Updated technology support for CDMA/EVDO, 802.1x, VPNs, and a text-to-speech engine Support for WVGA screen resolutions Speed improvements in searching and camera applications Gesture framework and GestureBuilder development tool 2.0/2.1 (Eclair) Based on Linux Kernel 2.6.29[39] On 26 October 2009 the 2.0 (Eclair) SDK was released.[40] Among the changes were:[41] Optimized hardware speed Support for more screen sizes and resolutions Revamped UI New Browser UI and HTML5 support New contact lists Better white-black ratio for backgrounds Improved Google Maps 3.1.2 Microsoft Exchange support Built in flash support for Camera Digital Zoom MotionEvent class enhanced to track multi-touch events[42] Improved virtual keyboard Bluetooth 2.1 Live Wallpapers The 2.0.1 SDK was released on 3 December 2009.[43] The 2.1 SDK was released on 12 January 2010.[44] 2.2 (Froyo)[45] Based on Linux Kernel 2.6.32[46] On 20 May 2010 the 2.2 (Froyo) SDK was released.[2] Changes included:[47] General Android OS speed, memory, and performance optimizations[48] Additional application speed improvements courtesy of JIT implementation[49] Integration of Chrome's V8 JavaScript engine into the Browser application Increased Microsoft Exchange support (security policies, auto-discovery, GAL look-up, calendar synchronization, remote wipe) Improved application launcher with shortcuts to Phone and Browser applications USB tethering and WiFi hotspot functionality Added an option to disable data access over mobile network Updated Market application with batch and automatic update features[48] Quick switching between multiple keyboard languages and their dictionaries Voice dialing and contact sharing over Bluetooth Support for numeric and alphanumeric passwords Support for file upload fields in the Browser application[50] Support for installing applications to the expandable memory[51] Adobe Flash 10.1 support[52] 3.0 (Gingerbread) Based on Linux Kernel 2.6.33 or 34[46] Tentatively scheduled for Q4 2010 launch. Confirmed new features: Support for WebM video playback[53] Improved copy–paste functionalities[54] Unconfirmed new features: Android Market music store[55] Media streaming from PC library[55] Revamped UI[56] [edit]Features


The Android Emulator default home screen (v1.5). Current features and specifications:[57][58][59] Handset layouts The platform is adaptable to larger, VGA, 2D graphics library, 3D graphics library based on OpenGL ES 2.0 specifications, and traditional smartphone layouts. Storage SQLite, a lightweight relational database, is used for data storage purposes Connectivity Android supports connectivity technologies including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi, and WiMAX. Messaging SMS and MMS are available forms of messaging, including threaded text messaging and now Android Cloud to Device Messaging Framework(C2DM) is also a part of Android Push Messaging service. Web browser The web browser available in Android is based on the open-source WebKit layout engine, coupled with Chrome's V8 JavaScript engine. The browser scores a 93/100 on the Acid3 Test. Java support While Android applications are written in Java, there's no Java Virtual Machine in the platform and Java byte code is not executed. Java classes get recompiled into Dalvik executable and run on Dalvik virtual machine. Dalvik is a specialized virtual machine designed specifically for Android and optimized for battery-powered mobile devices with limited memory and CPU. Android does not support J2ME, like some other mobile operating systems. Media support Android supports the following audio/video/still media formats: H.263, H.264 (in 3GP or MP4 container), MPEG-4 SP, AMR, AMR-WB (in 3GP container), AAC, HE-AAC (in MP4 or 3GP container), MP3, MIDI, Ogg Vorbis, WAV, JPEG, PNG, GIF, BMP.[59] Additional hardware support Android can use video/still cameras, touchscreens, GPS, accelerometers, magnetometers, accelerated 2D bit blits (with hardware orientation, scaling, pixel format conversion) and accelerated 3D graphics. Development environment Includes a device emulator, tools for debugging, memory and performance profiling, and a plugin for the Eclipse IDE. Market Like many phone-based application stores, the Android Market is a catalog of applications that can be downloaded and installed to target hardware over-the-air, without the use of a PC. Originally only free applications were supported. Paid-for applications have been available on the Android Market in the United States since 19 February 2009.[60] The Android Market has been expanding rapidly. As of April 30, 2010, it had over 50,000 Android applications for download.[61] Multi-touch Android has native support for multi-touch which was initially made available in handsets such as the HTC Hero. The feature was originally disabled at the kernel level (possibly to avoid infringing Apple's patents on touch-screen technology).[62] Google has since released an update for the Nexus One and the Motorola Droid which enables multi-touch natively.[63] Bluetooth Support for A2DP and AVRCP were added in version 1.5;[35] sending files (OPP) and accessing the phone book (PBAP) were added in version 2.0;[41] and voice dialing and sending contacts between phones were added in version 2.2.[47] Videocalling Not supported by default but as seen with the HTC Evo 4G, handset manufacturers can build front-facing cameras into their phones, so Qik, a software from the Android Market can use it for video-calling.[citation needed] Multitasking Multitasking of applications is available.[64]


Architecture Diagram [edit]Hardware running Android

Main article: List of Android devices The first phone to run the Android operating system was the HTC Dream, released on 22 October 2008.[65] [edit]Software development


Early Android device. The early feedback on developing applications for the Android platform was mixed.[66] Issues cited include bugs, lack of documentation, inadequate QA infrastructure, and no public issue-tracking system. (Google announced an issue tracker on 18 January 2008.)[67] In December 2007, MergeLab mobile startup founder Adam MacBeth stated, "Functionality is not there, is poorly documented or just doesn't work... It's clearly not ready for prime time."[68] Despite this, Android-targeted applications began to appear the week after the platform was announced. The first publicly available application was the Snake game.[69][70] The Android Dev Phone is a SIM-unlocked and hardware-unlocked device that is designed for advanced developers. While developers can use regular consumer devices purchased at retail to test and use their applications, some developers may choose not to use a retail device, preferring an unlocked or no-contract device. [edit]Software development kit The Android SDK includes a comprehensive set of development tools.[71] These include a debugger, libraries, a handset emulator (based on QEMU), documentation, sample code, and tutorials. Currently supported development platforms include x86-architecture computers running Linux (any modern desktop Linux distribution), Mac OS X 10.4.8 or later, Windows XP or Vista. Requirements also include Java Development Kit, Apache Ant, and Python 2.2 or later. The officially supported integrated development environment (IDE) is Eclipse (3.2 or later) using the Android Development Tools (ADT) Plugin, though developers may use any text editor to edit Java and XML files then use command line tools to create, build and debug Android applications as well as control attached Android devices (e.g., triggering a reboot, installing software package(s) remotely).[72] A preview release of the Android software development kit (SDK) was released on 12 November 2007. On 15 July 2008, the Android Developer Challenge Team accidentally sent an email to all entrants in the Android Developer Challenge announcing that a new release of the SDK was available in a "private" download area. The email was intended for winners of the first round of the Android Developer Challenge. The revelation that Google was supplying new SDK releases to some developers and not others (and keeping this arrangement private) has led to widely reported frustration within the Android developer community.[73] On 18 August 2008 the Android 0.9 SDK beta was released. This release provided an updated and extended API, improved development tools and an updated design for the home screen. Detailed instructions for upgrading are available to those already working with an earlier release.[74] On 23 September 2008 the Android 1.0 SDK (Release 1) was released.[75] According to the release notes, it included "mainly bug fixes, although some smaller features were added". It also included several API changes from the 0.9 version. On 9 March 2009, Google released version 1.1 for the Android dev phone. While there are a few aesthetic updates, a few crucial updates include support for "search by voice, priced applications, alarm clock fixes, sending gmail freeze fix, fixes mail notifications and refreshing intervals, and now the maps show business reviews". Another important update is that Dev phones can now access paid applications and developers can now see them on the Android Market.[76] In the middle of May 2009, Google released version 1.5 (Cupcake) of the Android OS and SDK. This update included many new features including video recording, support for the stereo bluetooth profile, a customizable onscreen keyboard system and voice recognition. This release also opened up the AppWidget framework to third party developers allowing anyone to create their own home screen widgets.[77] In September 2009 the "Donut" version (1.6) was released which featured better search, battery usage indicator and VPN control applet. New platform technologies included Text to Speech engine (not available on all phones), Gestures & Accessibility framework.[78] Android Applications are packaged in .apk format and stored under /data/app folder on the Android OS. The user can run the command adb root to access this folder as only the root has permissions to access this folder. [edit]App Inventor for Android On July 12, 2010 Google announced the availability of App Inventor for Android, a Web-based visual development environment for novice programmers, based on MIT's Open Blocks Java library and providing access to Android devices' GPS, accelerometer and orientation data, phone functions, text messaging, speech-to-text conversion, contact data, persistent storage, and Web services, initially including Amazon and Twitter. [79] "We could only have done this because Android’s architecture is so open," said the project director, MIT's Hal Abelson.[80] Under development for over a year[81], the block-editing tool has been taught to non-majors in computer science at Harvard, MIT, Wellsley, and the University of San Francisco, where professor David Wolber developed an introductory computer science course and tutorial book for non-computer science students based on App Inventor for Android.[82][83] [edit]Android Developer Challenge The Android Developer Challenge was a competition for the most innovative application for Android. Google offered prizes totaling 10 million US dollars, distributed between ADC I and ADC II. ADC I accepted submissions from 2 January to 14 April 2008. The 50 most promising entries, announced on 12 May 2008, each received a $25,000 award to fund further development.[84][85] It ended in early September with the announcement of ten teams that received $275,000 each, and ten teams that received $100,000 each.[86] ADC II was announced on 27 May 2009.[87] The first round of the ADC II closed on 6 October 2009.[88] The first-round winners of ADC II comprising the top 200 applications were announced on 5 November 2009. Voting for the second round also opened on the same day and ended on November 25. Google announced the top winners of ADC II on November 30, with SweetDreams, What the Doodle!? and WaveSecure being nominated the overall winners of the challenge.[89][90] [edit]Google applications Google has also participated in the Android Market by offering several applications for its services. These applications include Google Voice for the Google Voice service, Sky Map for watching stars, Finance for their finance service, Maps Editor for their MyMaps service, Places Directory for their Local Search, Google Goggles that searches by image, Google Translate, Google Shopper, Listen for podcasts and My Tracks, a jogging application. [edit]Third party applications With the growing number of Android handsets, there has also been an increased interest by third party developers to port their applications to the Android operating system. Famous applications that have been converted to the Android operating system include Shazam, Backgrounds, and WeatherBug. The Android operating system has also been considered important enough[weasel words] by a lot of the most popular internet sites and services to create native applications. These include MySpace, Facebook, and Twitter. As of 15th July 2010, the Android Marketplace had over 70,000 applications, with over 1 billion downloads.[91][92] [edit]Native code Libraries written in C and other languages can be compiled to ARM native code and installed using the Android Native Development Kit. Native classes can be called from Java code running under the Dalvik VM using the System.loadLibrary call, which is part of the standard Android Java classes.[93][94] Complete applications can be compiled and installed using traditional development tools.[95] The ADB debugger gives a root shell under the Android Emulator which allows native ARM code to be uploaded and executed. ARM code can be compiled using GCC on a standard PC.[95] Running native code is complicated by the fact that Android uses a non-standard C library (known as Bionic). The underlying graphics device is available as a framebuffer at /dev/graphics/fb0.[96] The graphics library that Android uses to arbitrate and control access to this device is called the Skia Graphics Library (SGL), and it has been released under an open source license.[97] Skia has backends for both win32 and Unix, allowing the development of cross-platform applications, and it is the graphics engine underlying the Google Chrome web browser.[98] [edit]Community-based firmware There is a community of open-source enthusiasts that build and share Android-based firmware with a number of customizations and additional features, such as FLAC lossless audio support and the ability to store downloaded applications on the microSD card.[99] This usually involves rooting the device. Rooting lets users load modified firmwares allowing users of older phones to use applications available only on newer releases.[100] Those firmware packages are updated frequently, incorporate elements of Android functionality that haven't yet been officially released within a carrier-sanctioned firmware, and tend to have fewer limitations. CyanogenMod is one such firmware. On 24 September 2009, Google issued a cease and desist letter[101] to the modder Cyanogen, citing issues with the re-distribution of Google's closed-source applications[102] within the custom firmware. Even though Android OS is open source, phones come packaged with closed-source Google applications for functionality such as the application store and GPS navigation. Google has asserted that these applications can only be provided through approved distribution channels by licensed distributors. Cyanogen has complied with Google's wishes and is continuing to distribute this mod without the proprietary software. He has provided a method to back up licensed Google applications during the mod's install process and restore them when it is complete.[103] [edit]Marketing


Android robot logo. [edit]Logos Android uses the Droid font family made by Ascender Corporation.[104] Android Green is the color of the Android Robot that represents the Android operating system. The print color is PMS 376C and the online hex color is #A4C639, as specified by the Android Brand Guidelines.[105] [edit]Typeface


Text logo. The custom typeface of Android is called Norad, only used in the text logo.[106] [edit]Market share Research company Canalys estimates that by Q2 2009, Android had a 2.8% share of the worldwide smartphone market.[107] By the following quarter (Q3 2009), Android's market share had grown to 3.5%.[108] In February 2010 ComScore ranked the Android platform as obtaining a 9.0% of the smartphone platform marketshare. This figure was up from an earlier estimate of 5.2% stated in November 2009.[109] In July 2010 ComScore revised Android's share for 3 months March/April/May 2010 to 13.0%, an increase of 4 percentage points, 0.2 percentage points behind Microsoft whose share had dropped 1.9%.[110] In October 2009, Gartner Inc. predicted that by 2012, Android would become the world's second most popular smartphone platform, behind Nokia's Symbian OS, which is very popular outside the US. Meanwhile, BlackBerry would fall from 2nd to 5th place, iPhone would remain in 3rd place, and Microsoft's Windows Mobile would remain in 4th place.[111] Analytics firm Flurry estimates that 250,000 Motorola Droid phones were sold in the United States during the phone's first week in stores.[112] In May 2010, Android's first quarter US sales surpassed that of the rival iPhone platform. According to a report by the NPD group, Android achieved 28% smartphone sales in the US market, up 8% from the December quarter. The iPhone's sales were flat at 21% over the same reporting period.[113] According to an interview with Eric Schmidt in The Guardian, Android is getting 160,000 new users per day (end June 2010) up from 100,000 per day in May 2010.[114] [edit]Restrictions and issues

Unlike closed-source mobile platforms like Apple's iOS, Google tracks issues and feature requests publicly at Google Code's site.[115] [edit]Linux compatibility Android's kernel was derived from Linux but has been tweaked by Google outside the main Linux kernel tree.[116] Android does not have a native X Window System nor does it support the full set of standard GNU libraries and this makes it difficult to port existing GNU/Linux applications or libraries to Android.[117] Google no longer maintains the code they previously contributed to the Linux kernel as part of their Android effort, effectively branching kernel code in their own tree, separating their code from Linux.[118][119][120] The code which is no longer maintained was deleted in January 2010 from the Linux codebase.[121] However, Google announced in April 2010 that they will employ staff to work with the Linux kernel community.[122] [edit]Networking issues Android did not support setting up a network proxy configuration for WiFi connections until Android 2.1 (Eclair).[123] Android does not support EAP extensions under WPA- and WPA2- Enterprise.[124] Android does not support Cisco-compatible IPsec virtual private networks (Layer 2 Tunneling Protocol is supported).[125] Android did not support wireless ad hoc networking until Android 2.2 (Froyo).[126] [edit]Issues concerning application development Android does not use established Java standards, i.e. Java SE and ME. This prevents compatibility among Java applications written for those platforms and those for the Android platform. Android only reuses the Java language syntax, but does not provide the full-class libraries and APIs bundled with Java SE or ME.[127] However, the Myriad Group claim that their new J2Android tool can convert Java MIDlets into Android applications.[128][129][130] Developers have reported that it is difficult to maintain applications on multiple versions of Android, owing to compatibility issues between versions 1.5 and 1.6,[131][132] especially the different resolution ratios in use among various Android phones.[133] Such problems were poignantly brought into focus as they were encountered during the ADC2 contest.[134] The rapid growth in the number of Android-based phone models with differing hardware capabilities also makes it difficult to develop applications that work on all Android-based phones.[135][136][137][138] As of June 2010, 50% of Android phones run the 2.1 version, and 24.6% still run the 1.5 version[139] Older versions of Android do not readily support Bluetooth file exchange,[140] although it may still be achieved with some hacking.[141] Bluetooth is supported by more recent phones.[142] Android does not support video calls as do other mobile operating systems, such as Symbian OS and Windows Mobile, although third-party, applications like Qik allow video calling on some models, and video broadcasting on others.[143] [edit]Time zones Using the native Google Calendar functionality for Android phones, an Android device user runs into the same limitations that exist in the Calendar application. The most noticeable defect is the lack of proper time zone support: it is not possible to set the time zone for start/end times of events.[144][145][146] Because of this issue, users experience difficulty while traveling with Android devices.[147]