Flutter BaseWidget 实现onResume、onPause()

在Flutter中，没有直接的生命周期回调像onResume和onPause。但是，你可以使用WidgetsBindingObserver接口来监听生命周期事件。

以下是一个简单的示例，展示如何在Flutter中实现类似Android的onResume和onPause：

import 'package:flutter/material.dart';
 
class LifecycleWatcher extends StatefulWidget {
  @override
  _LifecycleWatcherState createState() => _LifecycleWatcherState();
}
 
class _LifecycleWatcherState extends State<LifecycleWatcher> with WidgetsBindingObserver {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }
 
  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    super.didChangeAppLifecycleState(state);
    switch (state) {
      case AppLifecycleState.resumed:
        print('App is resumed');
        // Handle onResume
        break;
      case AppLifecycleState.inactive:
        print('App is inactive');
        // Handle onPause
        break;
      case AppLifecycleState.paused:
        print('App is paused');
        // Handle onPause
        break;
      case AppLifecycleState.detached:
        print('App is detached');
        // Handle cleanup
        WidgetsBinding.instance.removeObserver(this);
        break;
    }
  }
 
  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text('Lifecycle Watcher'),
      ),
    );
  }
}

在这个例子中，_LifecycleWatcherState类通过with WidgetsBindingObserver来扩展WidgetsBindingObserver接口。然后，它实现了didChangeAppLifecycleState方法来响应生命周期状态的变化。这里，resumed状态被视为onResume，而inactive和paused状态被视为onPause。记得在dispose方法中移除观察者，以防止内存泄漏。