flutter-motion

name	flutter-motion
description	Design and implement purposeful, performant, and accessible motion in Flutter. Use for transitions, micro-interactions, gesture feedback, animated state changes, shared elements, list choreography, reduced-motion behavior, or diagnosing animation quality and performance.

Flutter Motion

Use motion to explain change, causality, continuity, hierarchy, or feedback. Remove motion that communicates none of these.

Specify

1. Name the event, property change, user value, trigger, interruption behavior, and completion state.
2. Select the least complex Flutter mechanism that satisfies it: implicit animation, AnimatedSwitcher, explicit controller, hero transition, custom painter, or physics simulation.
3. Define duration ranges, curve character, sequencing, gesture relationship, and reduced-motion equivalent. Read references/motion.md. For multi-domain state changes, read references/connected-product-workflows.md and animate only the region whose state changed.
4. Check how the motion behaves during rapid taps, navigation interruption, rebuilds, route disposal, low frame budgets, and changed accessibility settings.

Implement

• Animate transform and opacity before layout-heavy properties when visually equivalent.
• Dispose controllers and avoid duplicated tickers.
• Preserve semantic state throughout transitions.
• Avoid delayed access to core actions.
• Keep list stagger subtle and bounded; never scale delay linearly across large collections.
• Provide immediate or cross-fade alternatives when reduced motion is requested.

Verify

Test at normal and reduced motion, under interruption, and on the lowest relevant performance tier. Inspect frame behavior when tooling permits. Report unmeasured performance instead of assuming smoothness.