Animate on a Path with Android Jetpack Compose UI
Article Summary
Phil Boyd from OkCupid shows how to build smooth path animations in Jetpack Compose using just high school math. No complex animation libraries required.
When OkCupid's design team requested arrows flying across the screen in curved paths, their Android team turned to Jetpack Compose. Instead of juggling multiple animation states, they used basic trigonometry and calculus to derive all animation properties from a single state value.
Key Takeaways
- Single state drives position, rotation, and trajectory using sine wave equations
- Derivative calculus calculates arrow rotation to match the curved path naturally
- Slotting pattern enables reusing the animation for multiple objects
- 4000ms linear animation with synchronized x and y offsets from one source
Critical Insight
Jetpack Compose lets you create complex path animations by deriving multiple properties from one animated state, eliminating the need to synchronize separate animation specs.
