What are the contents of an Android APK file

Question

• what are the components of the APK file ?
• Is it just bunch of executable\'s ?
• what are the names of the components ?

Answer 1

An APK file is an archive that usually contains the following folders:

• META-INF directory:

  • MANIFEST.MF: the Manifest file
  • CERT.RSA: The certificate of the application.

  • CERT.SF: The list of resources and SHA-1 digest of the corresponding lines in the MANIFEST.MF file; for example:

     Signature-Version: 1.0 
     Created-By: 1.0 (Android)  SHA1-Digest-Manifest:
     wxqnEAI0UA5nO5QJ8CGMwjkGGWE=  
     ...  
     Name: res/layout/exchange_component_back_bottom.xml  SHA1-Digest:
     eACjMjESj7Zkf0cBFTZ0nqWrt7w=  
     ...  
     Name: res/drawable-hdpi/icon.png 
     SHA1-Digest: DGEqylP8W0n0iV/ZzBx3MW0WGCA=
    

• lib: the directory containing the compiled code that is specific to a software layer of a processor, the folder is split into more folders within it:

  • armeabi: compiled code for all ARM based processors only
  • armeabi-v7a: compiled code for all ARMv7 and above based processors only
  • x86: compiled code for x86 processors only
  • mips: compiled code for MIPS processors only

• res: the directory containing resources not compiled into resources.arsc .

• assets: a directory containing applications assets, which can be retrieved by AssetManager.

• AndroidManifest.xml: An additional Android manifest file, describing the name, version, access rights, referenced library files for the application. This file may be in Android binary XML that can be converted into human-readable plaintext XML with tools such as AXMLPrinter2, apktool, or Androguard.

• classes.dex: The classes compiled in the dex file format understandable by the Dalvik virtual machine

  resources.arsc : a file containing pre-compiled resources, such as binary XML for example.

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