Implementing Twitter's App Loading Animation In React Native
Article Summary
Ever wonder how Twitter's delightful logo-to-app loading animation actually works? Eli White reverse-engineered it and the solution is counterintuitive.
This React Native tutorial breaks down Twitter's iOS app loading animation where the bird logo expands to reveal the app underneath. White walks through the wrong assumptions developers typically make, then explains the layering trick that makes it work using MaskedViewIOS and the Animated API.
Key Takeaways
- Animation uses 3 layers: blue background, white layer, and app (not overlay approach)
- MaskedViewIOS with Twitter logo masks both white and app layers simultaneously
- Single Animated.Value from 0-100 drives all timing with interpolated transforms
- useNativeDriver flag enables smooth 60fps animation without JavaScript thread jank
- Published as react-native-mask-loader npm package with full source code
Critical Insight
The key insight is using the logo as a mask for multiple layers rather than treating it as a transparent overlay, all driven by native animations for jank-free performance.
