I digged into the code since then and found that some critical APIs have been removed from Android 4.4 that flash uses. DAMN IT!
open failed: cannot locate symbol"_ZN7android10Vectorlmpl19reservedVectorlmpl 6Ev" referenced by "libflashplayer.so:..
After several days of coding, I finally found a way out with a hacked flash player. Being so excited and i can't wait wo share it. Here is the guide about how to install the hacked one and how to play flash content in the sites in Dolphin Browser.
1) Download Dolphin Browser
Surprised, Dolphin just push a 10.2.0 update version to me and I found Dolphin Jetpack was built-in. This means you don't have to install 2 separate APK now. Cheers！！
Here is the Download Link: https://play.google.com/store/apps/d...k.TunnyBrowser
Warning: [/B]You must have Dolphin Jetpack on in the settings to enjoy it. As far as I have noticed, Dolphin Jetpack better solves the compatibility with flash player, such as crash issue & freeze issue in full screen.
2) Download the hacked flash player HERE
Warning: Make sure that you have uninstall the flash player installed in your device and then install the hacked one for compatibility reason.
If your devices refused to install apk outside Google Play, you may set in your device (Settings> Securities> Unknown resources) to allow installation of apps from unknown sources.
3) Make sure that the flash setting in Dolphin Browser (Click Menu>Settings>Web Content>Flash Player) is on.
Flash Player is not officially supported and therefore the speed of loading of flash video may be slow. However, I have tried many sites such as YouTube and Hulu. They all work properly with satisfactory results.
Great thanks to @techfanatic9 for recording the video about How to Install Flash Player on Any Android KitKat Phone!
Here is the Video.