Having an .apk file, is there any way I can get its source code?
Even if ProGuard was used you still can get some interesting insights. Here is a StackOverflow question with a detailed explanation: Android: Getting source code from an APK file. YouTube video with a detailed guide. And a blog entry about that: How to retrieve source code from an Android APK file.
If you get lucky and your
.apk file wasn't protected by Proguard or analog, you can use APK tool. It is a tool for reverse engineering 3rd party, closed, binary Android apps.
Procedure for decoding .apk files, step-by-step method:
Make a new folder and copy over the .apk file that you want to decode.
Now rename the extension of this .apk file to .zip (e.g. rename from filename.apk to filename.zip) and save it. Now you can access the classes.dex files, etc. At this stage you are able to see drawables but not xml and java files, so continue.
Now extract this .zip file in the same folder (or NEW FOLDER).
Download dex2jar and extract it to the same folder (or NEW FOLDER).
Move the classes.dex file into the dex2jar folder.
Now open command prompt and change directory to that folder (or NEW FOLDER). Then write
d2j-dex2jar classes.dexand press enter. You now have the classes.dex.dex2jar file in the same folder.
Download java decompiler, double click on jd-gui, click on open file, and open classes.dex.dex2jar file from that folder: now you get class files.
Save all of these class files (In jd-gui, click File -> Save All Sources) by src name. At this stage you get the java source but the .xml files are still unreadable, so continue.
Now open another new folder
Put in the .apk file which you want to decode
Download the latest version of apktool AND apktool install window (both can be downloaded from the same link) and place them in the same folder
Download framework-res.apk and put it in the same folder (Not all apk file need this file, but it doesn't hurt)
Open a command window
Navigate to the root directory of APKtool and type the following command:
apktool if framework-res.apk
apktool d myApp.apk(where myApp.apk denotes the filename that you want to decode)
now you get a file folder in that folder and can easily read the apk's xml files.
It's not any step just copy contents of both folder(in this case both new folder)to the single one
and enjoy the source code...