Flutter 生命週期 StatefulWidget 生命週期 App 生命週期

StatefulWidget 生命週期

createState
initState
didChangeDependencies
build
(didUpdateWidget)

deactivate
dispose

App 生命週期

使用 WidgetsBindingObserver 監聽

class _MyScreenState extends State<MyScreen> with WidgetsBindingObserver

註冊監聽/解除監聽
initState: WidgetsBinding.instance.addObserver(this);
dispose: WidgetsBinding.instance.removeObserver(this);

//回調
@override
void didChangeAppLifecycleState(AppLifecycleState state) {
  super.didChangeAppLifecycleState(state);
  if (state == AppLifecycleState.paused) {
    // went to Background
  }
  if (state == AppLifecycleState.resumed) {
    // came back to Foreground
  }
}