Android application package

From Wikipedia, the free encyclopedia
  (Redirected from APK (file format))
Jump to: navigation, search
APK
APK format icon.png
Filename extension .apk
Internet media type application/vnd.android.package-archive
Type of format Package management system, file archive
Container for Software package
Extended from JAR and ZIP
Android phones, like the Galaxy Nexus, allow installation of applications directly via APK files or indirectly via Google Play

Android application package (APK) is the package file format used to distribute and install application software and middleware onto Google's Android operating system.

APK files are analogous to other software packages such as MSI packages 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".[1][2][3][4]

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 application/vnd.android.package-archive.[5]

Contents[edit]

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

  • 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 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
    • x86: compiled code for x86 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, 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.

Runtime Library[edit]

An APK requires Java runtime for the application to work. APK is installed mostly in Android devices. Up to Android KitKat, the default Runtime library for APK is Dalvik Runtime. Since the arrival of Android Lollipop, the runtime library has been changed from Dalvik to ART Runtime. ART is faster as compared to Dalvik. ART contains compiled .class files for applications which makes launching of applications faster and smoother. The compilation makes ART slow only one time on the first startup because of compilation process. Dalvik on the other hand compiles on the time of running an application. ART was introduced experimentally in some KitKat devices but now ART is the official runtime library being used in Android Applications in Android.

For Other Platforms[edit]

APK can generally be installed on Android devices because it is designed for it. However, APK is a java based application and it can be run anywhere with the correct form of runtime library available. APK can be installed in BBM OS 10.x and later because it has been introduced with Java Runtime library. Using special tools like Bluestacks, APK can be installed on Computers as well. APK might be available for other platforms in future as well.

See also[edit]

References[edit]

  1. ^ "Inside the Android Application Framework" (video). Google Sites. Google. 2008. 
  2. ^ Hatem Ben Yacoub (19 January 2008). "Tips: How to install apk files on Android Emulator". Open Handset Magazine. 
  3. ^ "The Structure of Android Package (APK) Files". OPhone SDN. OPhone Software Developer Network. 17 November 2010. 
  4. ^ chibucks (28 May 2010). "Learn to Fish: General Structure of an APK". SDX-Developers Forum. Simple Machines Forum. 
  5. ^ "Developer description of MIME type for .apk". Androidguys.com. 2008-10-21. Retrieved 2012-08-20. 

[1]

  1. ^ Ameen, Hayder. "Brain Dots for PC". DroidForPC. Retrieved 30 July 2015.