tencent/tinker

Tinker is a Java library for Android that solves a painful problem for mobile app developers: when you discover a bug in your published Android app, normally you have to release a new version, submit it to the app store, and wait for users to download and install the update. Tinker allows you to push a "hot fix", a small patch file, that updates the app on users' devices without requiring a full reinstall. This is called "hot-fixing." Specifically, Tinker can update three kinds of content in your app: the compiled code (dex files, which contain the Java logic of your app), native libraries (compiled code for low-level system operations), and resources (images, layouts, and other assets). Developers generate a patch file by comparing the old and new version of the app, then distribute that patch file to users through their own update mechanism. Tinker applies the patch when the app restarts. The library is developed by Tencent and is used in WeChat. It integrates with the standard Android build system (Gradle), you add it as a plugin, make a few configuration changes to your app's startup code, and then use Tinker's build tools to generate patches. There are some things Tinker cannot fix: it cannot update the app's manifest file (which declares core components), and hot-fixing is not permitted on Google Play, so this approach is more common in markets where apps are distributed outside of Google Play. The code is released under a BSD license.