There are two ways to install Android applications : online and offline. Online by going to the Android Market or Google Play, then select the application and Install it.
Offline install : we've got the installer file before, the name is APK file (Android Application Package), then we execute / run the APK file to start install it.
In this post will tell How to get the APK file from android application already installed on an Android device or tablet, so the file(APK) can be used as a backup or to be copied or installed on other android devices.
For example, your friend wants to copy an existing application from your Android tablet, you just send the APK file, sent via bluetooth or copy to USB, then your friend will install using offline mode on his/her device.
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