Alright, finally I have found the time to move the remaining information from the first post to its new place. Keep everything in one thread has become too hard to follow, so please use these new places:
This is Xposed version 2.4 beta1. The main new features and fixes in this version are:
Support for Android 4.4 (KitKat)
Significant performance improvements of the framework
Viewer for the debug.log in the installer
Check in the installer whether Xposed is actually active and working
First of all, I would like to thank the 45 people who donated to get me a Nexus 5, from a little "thanks" to huge amounts of money. I was really impressed and hope you like this update.
Xposed should now fully support KitKat. As mentioned, that wouldn't have been possible at this time without your support.
Modules should continue to work if they don't rely on AOSP internals that have changed in KitKat. One example: It seems that the battery icon is no longer an (animated) image, but a Java implementation. Obviously, any modules that try to replace the battery image will no longer work. The Xposed framework can't do anything here, the module needs to be rewritten. Therefore, if some of your modules don't work, please get in contact with the module author first. You will probably see an error in the new debug.log viewer in this case.
Xposed isn't compatible with ART, I can't say yet whether it will be in the future (will require a major rewrite if possible at all). As you would get into a bootloop if you try to combine Xposed+ART, Xposed automatically resets the choice to "Dalvik". If you want to test ART, you must uninstall the framework.
The performance improvements apply to the very core of Xposed, the method hooks, in all Android versions. In a test app developed by @exidler, the overhead per call used to be ~71 μs (= 0.071 ms) per call to a hooked method (with one empty callback handler) on my Galaxy S2. Now it's ~13 μs (= 0.013 ms). That's a relative improvement of factor ~5.5x. Thanks to @exidler for the research and several suggestions! I have sent a pre-beta to @kamso, who had reported lags with older versions. Now everything works fine for him. Anyway, I wouldn't say that Xposed had bad performance before. Keep in mind that we are talking about significantly less than a millisecond here.
The debug.log viewer should give a quick impression whether Xposed and modules could be loaded fine. It also includes options to save the log to SD card (so it's easier to transfer it to a PC etc.) and send it via mail.
The Xposed Installer now checks whether the latest version of the framework is active. If not (e.g. because it's not installed yet, you forgot to reboot or something in Xposed doesn't work), you will see a warning in the welcome screen and at the top of the module list.
Finally, there were some other minor improvements and fixes and new/updated translations.
As a reminder, please keep the debug.log clean. It's only helpful if it's not as spammed as logcat. You should only use XposedBridge.log() for error messages and other unexpected situations. If everything runs fine, it shouldn't write anything to the log. If you really need to keep some logging in published builds, please use either logcat or make it an opt-in options (i.e. disabled by default and the user enables it if he runs into problems).
Layout inflation hooks now also work if the layout has been included in other layouts. That's actually a pretty tricky use-case for the "extra" parameter mentioned about (and other tricky technologies).
If for some reason you need to determine the active XposedBridge version in your module, you can use XposedBridge.XPOSED_BRIDGE_VERSION.
findMethodBestMatch() now also looks for protected and package-private methods in superclasses. That's mainly useful if you use the callMethod() or callStaticMethod() helper.
The new beta should fix the "read-only filesystem" errors. If you used to experience them, please try this version. Otherwise, there is no need (and no advantage) to update.
The final version is out, please use it instead (see first post / in-app installer).
Regarding ART possibly becoming the default runtime engine: I think that's good news because it means that we will get a stable version of ART then. I'm reluctant to work further on ART support at the moment for mainly three reasons:
1. Time. I used to spend every evening and every weekend for Xposed, either to give support here (often answering the same questions again and again), writing code or researching about bugs or new ideas. As you may have noticed, there are now days or even weeks where I don't even log on to XDA, and I'm actually glad about this.
2. Experimental software is bound to contain bugs, even severe ones. There is a reason why Google didn't make this choice available for the typical user (and keep in mind, we are not typical users). I neither want people to blame Xposed if their phone starts acting up nor do I want to hunt bugs which are caused by a runtime engine that is explicitely labelled as not finished yet.
3. As long as ART is experimental, it's much easier to make big changes to the code. Once a final version is out and used by the masses, quality engineers we be much more careful not to break things. That means that Xposed for ART on 4.5 (or whatever it will be called) might need to be completely different than for ART on 4.4. More variants means more time for maintenance. And I don't feel like pushing something out now just to drop support again in a later version. There is not enough benefit of using ART at the moment to justify that.
You know, I had already worked on ART support and spent several dozens of hours reading the code, looking for ways to hijack it, implementing my ideas, doing trial and error and starting again from the beginning. I finally had my Nexus 5 boot with Xposed in early December and quickly tested the App Settings module. I'm happy about that, but I also know that this was just a very experimental version, less ready than ART itself. It is totally hacked together and only tested with the stock ROM. ART is quite complex and has several different modes. It's not worth giving the current development to someone else before I have tested these things on my phone, where I can debug much better than instructing someone else to do it. It also requires rewriting app_process to be a light executable again, which loads either the Dalvik or ART Xposed library, depending on your settings. That would require changes in the installer as well, etc. etc.
So you see, there is still lots of work to do. At the moment, I'm not actively working on it, but trying to get some other things fixed (e.g. LG ROMs) or improved (installation via recovery, better installation feedback in case root access failed, static Busybox package). And as I said, I do have other things in my life as well. It's not about money, that's what I have my full-time job for. I work on Xposed for fun (and maybe a bit for the reputation ), so the best way to ensure that I keep on working on it is not taking away the fun part of it. Don't pressure me like it was my duty to implement something ASAP (!!!), be patient even if it takes a bit longer until I answer and join the volunteers who help answering basic questions here so I don't have to. Thanks!
Announcement: Xposed Framework v2.5+ comes with an option to flash its own install zip via recovery, making my package obsolete. I'll leave them up for posterity; could be useful should the need arise for downgrading on some devices. Cheers all! 10000 downloads is pretty cool.
Xposed Framework v2.2+ has fixed JB4.3 installation and v2.4+ has added support for KK4.4, but for those that still want it, or cannot install via the APK due to /system write protection like HTC's S-ON, here is an updated zip frontend method for installing the framework; now for Xposed Framework v2.4.1.
You MUST have the Xposed Installer APK installed FIRST. The zip will detect if you do not and stop.
Flash this in recovery and my frontend script (the update-binary) will detect the correct architecture and SDK version to use the appropriate Xposed app_process and busybox builds (x86, armv5, v6 and v7 & sdk 15 and 16+ supported), and should detect the uid of the Xposed Installer APK on-the-fly and set up the required files with it.
It leaves a log behind in /data/local/tmp/xposed-log.txt either way with more details about how it went.
It also unpacks Xposed-Disabler-Recovery.zip to /sdcard/ (or /sdcard/0/ if it exists) to be as close to the APK install method as possible. For those wanting another method to reactivate after a ROM update or toggle Xposed disabled/enabled, @amishxda has also created a cool "Xposed toggler" zip here.
Note: Xposed Framework files and the install.sh used are the work of @rovo89 and @Tungstwenty; I have only created a recovery flashable zip to function as an alternative frontend for the framework installation process. I take no credit for their fantastic work.
P.S. If you found this handy then please check out my Odds and Ends thread for more flashable goodness.
5351 downloads of v2.1.4 when removed. 1049 downloads of v2.2 when removed.
This is Xposed version 2.5 (final). The main new features and fixes in this version are:
Rewritten framework installation/uninstallation
Uses interactive su (via libsuperuser) to provide improved compatibility with different Superuser apps
Better feedback when root access fails (doesn't freeze the app anymore)
Offers installation via custom recovery (CWM/TWRP), either flashing the file automatically or manually
Safemode to disable Xposed with hardware keys to get out of (most) bootloops
Compatibility with Sony/LG ROMs (4.3 and 4.4), Meizu ROMs (4.4)
Debug setting to disable resource hooking as a temporary workaround for incompatibilities with some theming engines (not all modules can be used in this mode)
There are also other improvements and fixes, especially many translations updates.
In case you get a message "Segmentation fault" during installation, you can now download an additional app which provides statically compiled versions of BusyBox (a lot bigger, but should work with every ROM). It's not needed otherwise.
Quick explanation of the safemode: It was developed by @Tungstwenty and makes it possible to disable Xposed by repeatedly pressing one of the hardware buttons during early startup. The phone will vibrate twice when the first key press has been detected. Then you have five seconds to press the same button four more times. Each key press will be confirmed with a short vibration; the final one with a long vibration. It creates /data/data/de.robv.android.xposed.installer/conf/disabled, which prevents most of Xposed's actions (e.g. no hooks are made and no modules are loaded). There's no 100% guarantee that this will get you out of a bootloop, but in most cases it should.