Android application package

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Filename extension.apk, .xapk
Internet media typeapplication/
Type of formatPackage format
Container forMobile apps
Extended fromJAR and ZIP

Android Package (APK)[1] is the package file format used by the Android operating system for distribution and installation of mobile apps and middleware.

APK analogous to other software packages such as APPX in Microsoft Windows or a Debian package in Debian-based operating systems. To make an APK file, a program for Android is first compiled, and then all of its parts are packaged into one container file. An APK file contains all of a program's code (such as .dex files), resources, assets, certificates, and manifest file. As is the case with many file formats, APK files can have any name needed, provided that the file name ends in the file extension ".apk".[2][3][4][5] APK files can be used to downgrade apps to an older file version (e.g. downgrade app version 78.9 to 55.1) by uninstalling the upgraded app and installing the older version via the "Unknown Sources" setting in settings (see below for more information).[6] This can be done for various reasons, such as an upgrade causing the app to repeatedly freeze and/or crash, the upgrade changing the app drastically (e.g. background too dark or too bright or preferred features not present, changed, or hidden), or restoring/removing something that the upgrade removed or installed. APK file is also a solution for installing apps/games which are limited because of restricted countries.[7]

APK files are a type of archive file, specifically in zip format-type packages, based on the JAR file format, with .apk as the filename extension. The MIME type associated with APK files is application/[8]

APK files can be installed on Android-powered devices just like installing software on a PC. When a user downloads an Android application using an android device, from an official source (such as the Google Play Store), it is automatically installed. The APK files can also be downloaded from the Google Play Store without installation, using a non-android device either through a Chrome or Firefox extension[9] or directly from unofficial sites.[10] Several Android apps can be used for the process of moving APK files between different devices (also called APK sideloading). Such apps include android file manager apps,[11] app orientation apps,[12] ... The installation of APK files outside of Google Play is disabled by default. Users can install unknown APK files by enabling "Unknown sources" from "Accounts and Security" in Settings.[13]

A user or developer can also install an APK file directly to a device (that is, not via download from the network) from a desktop computer, using a communication program such as adb.

Package contents[edit]

An APK file is an archive that usually contains the following files and directories:

  • META-INF directory:
    • MANIFEST.MF: the Manifest file
    • The certificate of the application.
    • CERT.SF: The list of resources and a 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 platform dependent; the directory is split into more directories within it:
    • armeabi: compiled code for all ARM based processors only
    • armeabi-v7a: compiled code for all ARMv7 and above based processors only
    • arm64-v8a: compiled code for all ARMv8 arm64 and above based processors only[14]
    • x86: compiled code for x86 processors only
    • x86_64: compiled code for x86 64 processors only
    • mips: compiled code for MIPS processors only
  • res: the directory containing resources not compiled into resources.arsc (see below).
  • 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 and by the Android Runtime.
  • resources.arsc: a file containing precompiled resources, such as binary XML for example.

See also[edit]


  1. ^ "Application Fundamentals | Android Developers". Android Developers. Retrieved 2018-12-03.
  2. ^ "Inside the Android Application Framework" (video). Google Sites. 2008.
  3. ^ Hatem Ben Yacoub (20 April 2018). "Tips: How to install apk files on Android Emulator". Open Ha Magazine. Archived from the original on 2012-05-26.
  4. ^ "The Structure of Android Package (APK) Files". OPhone SDN. OPhone Software Developer Network. 17 November 2010. Archived from the original on 8 February 2011.
  5. ^ chibucks (28 May 2010). "Learn to Fish: General Structure of an APK". SDX-Developers Forum. Simple Machines Forum. Archived from the original on 17 July 2012.
  6. ^ "What is an APK File and How to Install it?". Android Picks.
  7. ^ "What is apk?". 2019-08-08.
  8. ^ "Developer description of MIME type for .apk". 2008-10-21. Retrieved 2012-08-20.
  9. ^ Downloading APK files
  10. ^ Google Play Store alternatives to download APKs
  11. ^ 10 File explorer apps for android
  12. ^ Set Orientation for Android app
  13. ^ "What is an APK File and How to Install it?".
  14. ^ "ABI Management | Android Developers". Retrieved 16 June 2018.