lgvalle/material-animations

This repository is a reference guide for Android's built-in Transition Framework, which lets you add animation to mobile apps when moving between screens or changing what appears on a single screen. The repository is marked as no longer maintained, though the author notes the content remains valid as a learning reference. The framework handles three main scenarios. The first is animating the content of a screen when the user navigates from one activity (a page or screen in an Android app) to another. Three preset animation styles are available: Explode, where elements scatter outward from the center, Slide, where elements enter or exit from one side, and Fade, where elements gradually appear or disappear. You can define these either in XML files stored in your project or by writing code directly in Java. The second scenario is shared element transitions. This is the effect where a small thumbnail image on a list screen appears to grow and travel into its position on a detail screen. Both the origin and destination views must be tagged with the same transition name. The animation is an illusion: the two views remain separate objects in separate layouts, and the framework creates the appearance of movement between them. The third scenario involves animating changes within a single screen. A scene is a saved snapshot of what a layout looks like at a given moment. When you switch between scenes, the framework calculates what changed and animates the differences automatically. Elements can appear, disappear, or shift position with built-in transitions like ChangeBounds, which smoothly resizes and repositions views. The README explains all three scenarios with code samples in both XML and Java formats, and includes animated GIFs showing each transition in action. It also covers return and reenter transitions, which control the animation when the user navigates backward, and how to animate multiple shared elements simultaneously.