Android application package
|Internet media type||
|Type of format||Package format|
|Container for||mobile apps|
|Extended from||JAR and ZIP|
APK files are analogous to other software packages such as APPX in Microsoft Windows or Deb packages in Debian-based operating systems like Ubuntu. To make an APK file, a program for Android is first compiled, and then all of its parts are packaged into one file. An APK file contains all of that 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 ".apk".
APK files are a type of archive file, specifically in zip format packages based on the JAR file format, with
.apk as the filename extension. The MIME type associated with APK files is
APK files can be installed on Android powered devices just like installing software on PC. To secure the device, there is an "Unknown sources" setting in Settings menu which is disabled by default. It must be enabled before installing any application with APK file. Enabling this setting is not required when you are installing a package via an official source (such as Google Play).
An APK file is an archive that usually contains the following files and directories:
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 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 
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
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, android-apktool, or Androguard.
classes.dex: The classes compiled in the dex file format understandable by the Dalvik virtual machine
resources.arsc: a file containing precompiled resources, such as binary XML for example.
- "Inside the Android Application Framework" (video). Google Sites. Google. 2008.
- Hatem Ben Yacoub (19 January 2008). "Tips: How to install apk files on Android Emulator". Open Handset Magazine.
- "The Structure of Android Package (APK) Files". OPhone SDN. OPhone Software Developer Network. 17 November 2010.
- chibucks (28 May 2010). "Learn to Fish: General Structure of an APK". SDX-Developers Forum. Simple Machines Forum.
- "Developer description of MIME type for .apk". Androidguys.com. 2008-10-21. Retrieved 2012-08-20.
- "What is an APK File and How to Install it?". Android Picks.