firebase - 如何避免将分析传递到小部件树中？

Question

我想通过Firebase分析在Flutter应用中跟踪选项卡更改。在示例应用程序中，它们只是将FirebaseAnalyticsObserver传递给了小部件树:

class MyApp extends StatelessWidget {
  static FirebaseAnalytics analytics = FirebaseAnalytics();
  static FirebaseAnalyticsObserver observer =
      FirebaseAnalyticsObserver(analytics: analytics);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Firebase Analytics Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      navigatorObservers: <NavigatorObserver>[observer],
      home: MyHomePage(
        title: 'Firebase Analytics Demo',
        analytics: analytics,
        observer: observer,
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title, this.analytics, this.observer})
      : super(key: key);

  final String title;
  final FirebaseAnalytics analytics;
  final FirebaseAnalyticsObserver observer;

  @override
  _MyHomePageState createState() => _MyHomePageState(analytics, observer);
}

class _MyHomePageState extends State<MyHomePage> {
  _MyHomePageState(this.analytics, this.observer);

  final FirebaseAnalyticsObserver observer;
  final FirebaseAnalytics analytics;

但是问题是我的选项卡页面远远低于小部件树。因此很难一路走下去。

如何初始化FirebaseAnalytics观察器以跟踪正常的屏幕路线，但也可以将其提供给标签页？

我正在使用Provider和ChangeNotifier。所以也许我可以初始化一个服务，然后提供下来？例如

class Analytic extends ChangeNotifier {

static FirebaseAnalyticsObserver observer =
FirebaseAnalyticsObserver(analytics: analytics);
}

Answer 1

Flutter有一个InheritedWidget，它是一个完全做到这一点的小部件，它一直向下传递数据，您可以检查official video showcase或某些articles。

要使用它，您可以将widget与Inheritedwidget一起包装

class MyApp extends StatelessWidget {
  final FirebaseAnalytics analytics = FirebaseAnalytics();//don't make this static please
  final FirebaseAnalyticsObserver observer =
      FirebaseAnalyticsObserver(analytics: analytics); //don't make this static please

  @override
  Widget build(BuildContext context) {
    return ObserverProvider(
    child: MaterialApp(
      title: 'Firebase Analytics Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      navigatorObservers: <NavigatorObserver>[observer],
      home: MyHomePage(
        title: 'Firebase Analytics Demo'
      ),
    ),
    observer:observer,
    analytics:analytics
    )
    ;
  }
}


class ObserverProvider extends InheritedWidget {
  const ObserverProvider(
      {Widget child,
      Key key,
      this.observer,
      this.analytics})
      : super(key: key, child: child);
  final FirebaseAnalytics analytics;
  final FirebaseAnalyticsObserver observer;

  static ObserverProvider of(BuildContext context) {
    return (context.inheritFromWidgetOfExactType(ObserverProvider));
  }

  @override
  bool updateShouldNotify(ObserverProvider e) => false;
}

如果要访问数据，则可以为观察者调用 ObserverProvider.of(context).observer，为分析调用 ObserverProvider.of(context).analytics