Generally speaking, if you want to get into Android app development, you have to get into Java. With current techniques, we can compile and decompile APKs to modify them. Often times, though, it’s better to see the app as it was written.
XDA Recognized Contributor broodplank1337 released a tool that turns APKs into Java. There are a lot of uses for such a tool, but the main ones include educational purposes and to help further mod applications. In addition to decompiling APK files to Java, the tool performs a number of other functions. As broodplank1337 explains:
Additionally it also can decompile to smali code and it can decompile the resources of the app. It’s currently a very early beta but it works successfully.
This tool can be useful to a number of different users. Modders and themers now have better access to the app to better change it. People looking to learn more about Android app development can check out a favorite app and see how it’s done.
To learn more, check out the original thread._________