Flutter WidgetsBindingObserver 的 didChangeAppLifecycleState 未在 Windows 桌面上调用

Question

The print functions should be called according to the lifecycle transitions, but none of them are being called. To test this, I'm running the app in debug mode and moving it to the background/foreground (ie changing to another app and then returning to this app).

What am I doing wrong?

import 'package:flutter/material.dart';

class StopwatchVw extends StatefulWidget {
  const StopwatchVw({Key? key}) : super(key: key);
  @override _StopwatchVwState createState() => _StopwatchVwState();
}

class _StopwatchVwState extends State<StopwatchVw> with WidgetsBindingObserver {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance!.addObserver(this);
  }

  @override
  Future<void> didChangeAppLifecycleState(AppLifecycleState state) {
    print('Changed');

    switch (state) {
      case AppLifecycleState.inactive:
        print("Inactive");
        break;
      case AppLifecycleState.paused:
        print("Paused");
        break;
      case AppLifecycleState.resumed:
        print("Resumed");
        break;
      case AppLifecycleState.detached:
        print("Suspending");
        break;
    }
  }

  @override
  void dispose() {
    WidgetsBinding.instance!.removeObserver(this);
    super.dispose();
  }

  @override
    Widget build(BuildContext context) {
      return Scaffold(body: Text('HEY'));
    }

This is my main.dart:

import 'package:bitsdojo_window/bitsdojo_window.dart';
import 'package:clocker/stopwatch_vw.dart';
import 'package:flutter/material.dart';
import 'package:flutter_acrylic/flutter_acrylic.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Window.initialize();
  await Window.hideWindowControls();

  runApp(const MyApp());

  doWhenWindowReady(() {
    const initialSize = Size(350, 200);
    appWindow
      ..size = initialSize
      ..minSize = initialSize
      ..maxSize = initialSize
      ..alignment = Alignment.bottomRight
      ..show();
  });

  Window.setEffect(
    effect: WindowEffect.acrylic,
    color: const Color.fromARGB(29, 250, 250, 227),
  );
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MoveWindow(child: const StopwatchVw())
    );
  }
}

Answer 1

Flutter currently doesn't support LifeCycle events on the desktop, But there is an existing issue which is being tracked here #30735 .

Currently, you can determine the status of your application with the window_manager package

class Windows extends StatefulWidget {
  const Windows({super.key});

  @override
  State<Windows> createState() => _WindowsState();
}

class _WindowsState extends State<Windows> with WindowListener {
  @override
  void onWindowClose() {
    // do something
  }

  @override
  void onWindowFocus() {
    // do something
  }
  @override
  void onWindowMinimize() {
    // do something
  }
  
  @override
  void initState() {
    windowManager.addListener(this);
    super.initState();
  }

  @override
  void dispose() {
    windowManager.removeListener(this);
    super.dispose();
  }