本文共 4188 字，大约阅读时间需要 13 分钟。

监听路由堆栈的变化使用 RouteObserver ，首先在 MaterialApp 组件中添加 navigatorObservers：

void main() {  runApp(MyApp());}RouteObserver
   
     routeObserver = RouteObserver
    
     ();class MyApp extends StatelessWidget {  @override  Widget build(BuildContext context) {    return MaterialApp(      ...      navigatorObservers: [routeObserver],      home: HomePage(),    );  }}
    
   

监听页面设置如下：

class ARouteObserverDemo extends StatefulWidget {  @override  _RouteObserverDemoState createState() => _RouteObserverDemoState();}class _RouteObserverDemoState extends State
   
     with RouteAware {  @override  void didChangeDependencies() {    super.didChangeDependencies();    routeObserver.subscribe(this, ModalRoute.of(context));  }  @override  Widget build(BuildContext context) {    return Scaffold(      body: Container(        alignment: Alignment.center,        child: RaisedButton(          child: Text('A RouteObserver'),          onPressed: () {            Navigator.of(context).pushNamed('/BRouteObserver');          },        ),      ),    );  }  @override  void dispose() {    super.dispose();    routeObserver.unsubscribe(this);  }  @override  void didPush() {    final route = ModalRoute.of(context).settings.name;    print('A-didPush route: $route');  }  @override  void didPopNext() {    final route = ModalRoute.of(context).settings.name;    print('A-didPopNext route: $route');  }  @override  void didPushNext() {    final route = ModalRoute.of(context).settings.name;    print('A-didPushNext route: $route');  }  @override  void didPop() {    final route = ModalRoute.of(context).settings.name;    print('A-didPop route: $route');  }}
   

其中 didPush、didPushNext、didPopNext、didPop 为路由堆栈变化的回调。

从 A 页面跳转到 ARouteObserverDemo 页面，日志输出如下：

flutter: A-didPush route: /ARouteObserver

进入此页面只调用了 didPush。

从 ARouteObserverDemo 页面跳转到 BRouteObserverDemo 页面（同 ARouteObserverDemo 页面，设置了监听），日志输出如下：

flutter: A-didPushNext route: /ARouteObserverflutter: B-didPush route: /BRouteObserver

先调用了 ARouteObserverDemo 页面的 didPushNext，然后调用了 BRouteObserverDemo 页面的 didPush。

从 BRouteObserverDemo 页面执行 pop 返回 ARouteObserverDemo 页面，日志输出如下：

flutter: A-didPopNext route: /ARouteObserverflutter: B-didPop route: /BRouteObserver

先调用了 ARouteObserverDemo 页面的 didPopNext，然后调用了 BRouteObserverDemo 页面的 didPop。

上面的案例仅仅是页面级别的路由堆栈变化，如果想知道整个应用程序路由堆栈变化如何处理？

一种方法是写一个监听路由堆栈的基类，所有页面继承此基类。此方法对源代码的侵入性非常高。

还有一种方法是自定义 RouteObserver，继承RouteObserver并重写其中的方法：

class MyRouteObserver
   
    > extends RouteObserver
    
      {  @override  void didPush(Route route, Route previousRoute) {    super.didPush(route, previousRoute);    print('didPush route: $route,previousRoute:$previousRoute');  }  @override  void didPop(Route route, Route previousRoute) {    super.didPop(route, previousRoute);    print('didPop route: $route,previousRoute:$previousRoute');  }  @override  void didReplace({Route newRoute, Route oldRoute}) {    super.didReplace(newRoute: newRoute, oldRoute: oldRoute);    print('didReplace newRoute: $newRoute,oldRoute:$oldRoute');  }  @override  void didRemove(Route route, Route previousRoute) {    super.didRemove(route, previousRoute);    print('didRemove route: $route,previousRoute:$previousRoute');  }  @override  void didStartUserGesture(Route route, Route previousRoute) {    super.didStartUserGesture(route, previousRoute);    print('didStartUserGesture route: $route,previousRoute:$previousRoute');  }  @override  void didStopUserGesture() {    super.didStopUserGesture();    print('didStopUserGesture');  }}
    
   

使用：

void main() {  runApp(MyApp());}MyRouteObserver
   
     myRouteObserver = MyRouteObserver
    
     ();class MyApp extends StatelessWidget {  @override  Widget build(BuildContext context) {    return MaterialApp(      title: 'Flutter Demo',      navigatorObservers: [myRouteObserver],      initialRoute: '/A',      home: APage(),    );  }}
    
   

此时从 A 页面 跳转到 B 页面，日志输出如下：

flutter: didPush route: MaterialPageRoute
   
    (RouteSettings("/B", 来自A), animation: AnimationController#6d429(▶ 0.000; for MaterialPageRoute
    
     (/B))),previousRoute:MaterialPageRoute
     
      (RouteSettings("/A", null), animation: AnimationController#e60f7(⏭ 1.000; paused; for MaterialPageRoute
      
       (/A)))
      
     
    
   

转载地址：http://juhni.baihongyu.com/