HOW-TO Decompile and Compile apps using Apktool in 5 Simple Steps

What you need before you learn how to use apktool -

1. A computer running windows
2. A working internet connection for downloading the following -
   • JAVA SDK and JRE
   • Android SDK
   • Apktool core tool
   • Sign apk tool
3. Basic command prompt commands and path knowledge
4. A good linux format code editing program like NotePad ++ [Get it from HERE]

  STEP 1 - Install JAVA - Go HERE

• Just go to the above website and download java SDK and JRE.
• We mostly use only SDK libraries but JRE is required when you want to modify games or apps like whatsapp. So its best if we install both.
• install them in any directory for example C:\ drive and you are good to go to next step 2.

 STEP 2 - Install Android SDK- Go HERE

• Just go to the above website and download the SDK.
• Install it in an easy path. For example - C:\android
• The short path will be useful when you are using adb for logcat purposes, since typing in a long path every-time you want to access the adb executable file is painful.
• So once you installed the SDK move on to next step 3

  STEP 3 - Download Apktool - Go HERE

• For downloading apktool related files, you need to go HERE
• Download latest apktool version, currenlty 1.5.2
• Download the batch file and aapt.exe
• Create a folder anywhere in the pc and put all the apktool.jar, aapt.exe and the batch script in that folder. [see screenshot]
• This will be the operating folder for you now.
• Next move to next step 4

 STEP 4 - Using apktool for decompiling anything

• Open command prompt
• navigate to the folder where you placed apktool.jar, batch script and the aapt.exe [see screenshot]
• For this guide i am using a simple framework-res.apk for reference.
• Once you are in the folder via cmd prompt, you need to install the file using the " IF " command
• type the following command -

apktool if name-of-app.apk

• Once the app is installed you need to decompile it.
• For decompiling use the command "d". The "d" stands for decompile.

 apktool d name-of-the-app.apk

 

After the app is correctly decompiled, a new folder will be created in the same folder where you placed your app. This contains all the xml's and smali files which can be edited for different mod's.

 

• Then after you are finished with your modding, you need to recompile your app for using it.
• To recompile the app use the following command " B ". The "b" simply means recompile.

code

apktool b name-of-app-folder

• NOTE - While recompiling the app, you just need to type the name of the folder the app's files contains.
   
•  
• Congrats ! If everything went well, you successfully created a modified app ! 
• Now the most important step is below in step 5

STEP 5 - Signing the apk


• to sign an apk download the "sign-apk.rar" from below attachements
• extract it to any place.
• open a new command prompt and change into the sign-apk directory using cmd
• move the modified-unsigned apk into this folder

code

 java -jar signapk.jar certificate.pem key.pk8 path-of-the-folder-contaning-the-apk .apk path-of-the-new-signed-apk .apk



• This is FINAL APK. 
• Simply rename it to the original apk and push it into the system ! DONE 

 Source :xda-developers

 Download  SignApk