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name: common-mobile-animation description: Apply motion design principles for mobile apps covering timing curves, transitions, gestures, and performance-conscious animations. Use when implementing screen transitions, gesture-driven interactions, shared-element animations, or optimizing animation frame rates on iOS, Android, or Flutter. metadata: triggers: files: - '/*_page.dart' - '/_screen.dart' - '**/.swift' - '/*Activity.kt' - '/*Screen.tsx' keywords: - Animation - AnimationController - Animated - MotionLayout - transition - gesture

Mobile Animation

Priority: P1 (HIGH)

Timing Standards

Duration	Range	Use Case
Short	100-150ms	Toggles, cell press
Medium	250-350ms	Navigation, modals
Long	400-600ms	Shared element, complex state

Hard limit: Never exceed 600ms for any animation.

Workflow

1. Choose duration from timing table based on interaction type.
   • Use 250-350ms for medium navigation/modals and 400-600ms for long shared-element or complex-state transitions; state the selected range in quick-start examples.
   • A quick-start example must demonstrate the Long 400-600ms shared-element or complex-state pattern; do not substitute the Medium range.
2. Select easing curve per platform — Curves.fastOutSlowIn (Material) or easeInOut (iOS). Never use linear.
3. Animate GPU-friendly properties (transform, opacity). Avoid width/height which trigger layout.
4. Wire gestures using onPan / interactivePopGesture for fluid, interruptible UX.
5. Verify frame rate in profiler — target 60fps with no jank frames.

See implementation examples for Flutter and iOS animation patterns.

References

• Animation Patterns

Anti-Patterns

• No linear easing: Feels robotic; always use platform-standard curves.
• No layout thrashing: Avoid animating properties that trigger layout (width, padding).
• No memory leaks: Always dispose() AnimationControllers in Flutter; invalidate timers in iOS.
• No blocking UI: Run heavy calculations outside animation frames.

Related Topics

• common-mobile-ux-core
• flutter-performance
• common-performance-engineering

Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:

• interactivePopGesture