Android-apktools is a tools reverse engineering 3rd party, closed, binary Android apps. dex2jar is a tools to work with android .dex and java .class files. JD-GUI is a standalone graphical utility that displays Java source codes of “.class” files. You can browse the reconstructed source code with the JD-GUI for instant access to methods and fields.
Decompiler android resouce file use Android-apktools. Download
apktool1.5.2.tar.bz2, unzip to a same folder, run
apktool d -f xxx.apk xxx.
Decompiler android java file use dex2jar, unzip a classes.dex from apk, run ./d2j-dex2jar.sh classes.dex, then you will got the file named classes-dex2jar.jar.
Use JD-GUI open classes-dex2jar.jar, you'll say the java source.