Decompress APK file
Use 7zip to decompress the APK file (this is a ZIP compressed container)
Method 1: dex -> jar -> java classes
- The file “classes.dex” can be converted to a JAR file with the following tool: dex2jar
- Decompress the JAR file using 7zip again.
- Now you will get Java class files. These files you can decompile with the tool JAD.
jad.exe -o -r -sjava -dsdrc C:/classes_dex2jar/**/*.class
Method 2: dex -> smali
To decompile and recompile the classes.dex file you can use this tool: ROMToolsPCv3
You will get smali files instead of java class files. The smali files can be modified and recompiled to classes.dex file again. How to do this you can read here: [GUIDE] Smali coding guide for beginners.