Animations can affect your app's frame rate and battery life. Smooth animations target 60 frames per second (fps) for a fluid feel. On ProMotion devices, 120fps is ideal. Poorly optimized animations can cause frame drops, making the app feel slow or laggy. They also use CPU and GPU resources, which can increase battery consumption if overused.
To keep animations smooth at 60fps, use native animation APIs like UIViewPropertyAnimator or Core Animation. Avoid heavy computations during animations. Pre-render images and use vector assets when possible. Limit simultaneous animations and prefer implicit animations over manual frame updates. Test on real devices to ensure consistent performance.
Animations themselves add minimal size if using code-based animations. However, large image sequences or video-based animations can increase app bundle size significantly. This can slow app download and startup time. Use lightweight vector animations (e.g., Lottie files) or system animations to keep size small and startup fast.
On iOS, animations use UIKit and Core Animation frameworks, which are highly optimized for smoothness and battery efficiency. Android uses Jetpack Compose or XML animations with different performance characteristics. iOS offers ProMotion support for higher frame rates. Developers should test animations on both platforms to adjust for hardware and OS differences.
Apple's App Store guidelines emphasize smooth, responsive user interfaces. Apps with janky or freezing animations may be rejected for poor user experience. Avoid animations that cause confusion or motion sickness. Provide options to reduce motion for accessibility. Ensure animations do not interfere with app functionality or accessibility features.
Your app takes 5 seconds to load this screen with animations. What's likely wrong?