Lifecycle of a Widget
summary
Explains concrete internals: widgets create elements, render-object widgets produce render objects, and stateless/stateful classes are just immutable configs while state objects and elements hold the lifecycle. Identifies five scheduler phases (idle, transient callbacks, mid-frame microtasks, persistent callbacks, post-frame) and shows APIs: schedulerBinding.instance, WidgetsFlutterBinding.ensureInitialized, PlatformDispatcher → drawFrame, BuildOwner.buildScope. Notes setState closure runs synchronously (asserts removed in production) and that addPostFrameCallback introduces a one-frame delay before changes take effect.
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chapters (8)
- 0:00Introduction to widget lifecycle
- 4:03Flutter tree structures explained
- 15:07Rendering phases in Flutter
- 22:09Element lifecycle deep dive
- 27:07Frame rendering process
- 33:08State object lifecycle
- 38:50Post-frame callbacks
- 40:57Summary and Q&A
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