flutter - Flutter-SnackBar 未显示在 TabBarView 中

Question

这是来自 Flutter.io 的官方标签演示。我想在一个由 RadioButton 触发的选项卡中添加小吃栏。

我确实将它包装在一个 Scaffold 小部件中。它不在 TabBarView 中工作，而是在单个单选按钮中工作。但是当我将 Snackbar 放在选项卡中时，什么也没有显示。

代码的主要部分如下所示

class MyApp extends StatelessWidget {
  @override
   Widget build(BuildContext context) {
     return new MaterialApp(
       title: 'Flutter Demo',
       theme: new ThemeData(

       primarySwatch: Colors.blue,
       ),
       home: new DefaultTabController(
        length: 3,
        child: new Scaffold(
        appBar: new AppBar(
          bottom: new TabBar(tabs: [
            new Tab(icon: new Icon(Icons.home)),
            new Tab(icon: new Icon(Icons.favorite)),
            new Tab(icon: new Icon(Icons.list))
          ]),
          title: new Text("Tabs Demo"),
        ),
        body: new TabBarView(children: [
          new MyHomePage(),
          new Center(
              child: new RaisedButton(
                onPressed: () {
                  final snackBar = new SnackBar(
                    content: new Text('Yay! A SnackBar!'),
                    action: new SnackBarAction(
                      label: 'Undo',
                      onPressed: () {
                        // Some code to undo the change!
                      },
                    ),
                  );

                  // Find the Scaffold in the Widget tree and use it to show a SnackBar!
                  Scaffold.of(context).showSnackBar(snackBar);
                },
                child: new Text('Show SnackBar'),
              )
          ),
            new Center(
              child: new IconButton(icon: new Icon(Icons.add), onPressed: (){
                final snackBar = new SnackBar(
                  content: new Text('Yay! A SnackBar!'),
                  action: new SnackBarAction(
                    label: 'Undo',
                    onPressed: () {
                      // Some code to undo the change!
                    },
                  ),
                );

                // Find the Scaffold in the Widget tree and use it to show a SnackBar!
                Scaffold.of(context).showSnackBar(snackBar);
              })
            ),
        ]),
      )),
);
}
 }

标签： flutter

Answer 1

Add a GlobalKey of the Scaffold state and use that to display SnackBar as below,

GlobalKey<ScaffoldState> scaffoldState = new GlobalKey();

Scaffold(
key: scaffoldState,

....

scaffoldState.currentState.showSnackBar(new SnackBar(content: new Text('Hello!')));

....

);