This project makes it possible to run apktool on android,in other words,you can decompile and recompile apk file without a computer,just with your android phone! What you need to do is:
1)extract the archive apktool4.1_armhf.zip or apktool4.1_armel.zip to /sdcard;
2)install /sdcard/apktool/apktool4.1.apk
then open the application.
Please uninstall old version before installing a new version!