Flutter与Native生命周期对比

秒速五厘米 2023-07-20 13:55 30阅读 0赞

[AppLifecycleState][]枚举类定义了Flutter生命周期的类型，通过**WidgetsBindingObserver**来监听AppLifecycleState。**AppLifecycleState**有四种状态：**inactive**、**paused**、**reasumed**、**detached**（以前还有个suspending，已过期）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3ZpdGF2aXZh_size_16_color_FFFFFF_t_70][]

它们与Android和IOS的生命周期对应关系如下表：

<table style="width:500px;"> 
 <thead> 
  <tr> 
   <th>状态</th> 
   <th>说明</th> 
   <th>Android</th> 
   <th>iOS</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>inactive</td> 
   <td>界面退到后台或弹出对话框情况下， 即失去了焦点但仍可以执行drawframe回调</td> 
   <td>onPaus</td> 
   <td>viewDidLoad</td> 
  </tr> 
  <tr> 
   <td>paused</td> 
   <td>应用挂起，比如退到后台，失去了焦点且不会收到drawframe回调</td> 
   <td>onStop</td> 
   <td>viewWillDisappear viewDidDisappear</td> 
  </tr> 
  <tr> 
   <td>resumed</td> 
   <td>从后台切换前台，界面可见</td> 
   <td>onResume</td> 
   <td> <p>viewWillAppear</p> <p>viewDidAppear</p> </td> 
  </tr> 
  <tr> 
   <td>detached</td> 
   <td>APP结束时调用</td> 
   <td>onDestroy</td> 
   <td>dealloc</td> 
  </tr> 
 </tbody> 
</table>

通过sample实际测试一下生命周期的回调时机

class _MyHomePageState extends State<MyHomePage> with WidgetsBindingObserver {
    
      AppLifecycleState _state;
    
      @override
      void initState() {
        super.initState();
        WidgetsBinding.instance.addObserver(this);
      }
    
      @override
      void dispose() {
        WidgetsBinding.instance.removeObserver(this);
        super.dispose();
      }
    
      @override
      void didChangeAppLifecycleState(AppLifecycleState state) {
        print('state = $state');
      }

## APP启动 ##

--------------------

无事件发生

# 屏幕旋转 #

--------------------

无事件发生

## APP结束 ##

--------------------

I/flutter (13730): state = AppLifecycleState.inactive
    I/flutter (13730): state = AppLifecycleState.paused
    I/flutter (13730): state = AppLifecycleState.detached

## 点击HOME键 ##

--------------------

I/flutter (13730): state = AppLifecycleState.inactive
    I/flutter (13730): state = AppLifecycleState.paused

## 关屏幕 ##

--------------------

I/flutter (15366): state = AppLifecycleState.inactive
    I/flutter (15366): state = AppLifecycleState.paused

# #

[AppLifecycleState]: https://docs.flutter.io/flutter/dart-ui/AppLifecycleState-class.html
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