最近在玩flutter，遇到了snackbar弹不出的情况，log显示这个
显示不出 snackbar 的代码差不多长这样，由于我的代码高亮插件不支持dartlang，就用java代替一下了。。
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import 'package:flutter/material.dart'; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( primarySwatch: Colors.blue, ), home: MyHomePage(title: 'Flutter Demo Home Page'), ); } } class MyHomePage extends StatefulWidget { MyHomePage({Key key, this.title}) : super(key: key); final String title; @override _MyHomePageState createState() => _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(widget.title), ), body: Center( child: RaisedButton( onPressed: () { print("Tap"); Scaffold.of(context) .showSnackBar(new SnackBar(content: Text('Test'))); }, child: new Container( padding: new EdgeInsets.all(12.0), child: new Text('Flat Button'), ), )), ); } } |
我的解决解决方法是，新建个snackbar类，内容如下。
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import 'package:flutter/material.dart'; class snackBar { static SnackBarByKey(final GlobalKey<ScaffoldState> scaffoldkey, BuildContext context, String str) { final snackBar = new SnackBar(content: new Text(str)); scaffoldkey.currentState.showSnackBar(snackBar); } } |
然后在 main.dart import 这个文件，再修改一下代码，添加一个globalkey，改成这样
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import 'package:flutter/material.dart'; import './snackbar.dart'; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( primarySwatch: Colors.blue, ), home: MyHomePage(title: 'Flutter Demo Home Page'), ); } } class MyHomePage extends StatefulWidget { MyHomePage({Key key, this.title}) : super(key: key); final String title; @override _MyHomePageState createState() => _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey(); @override Widget build(BuildContext context) { return Scaffold( key: scaffoldKey, appBar: AppBar( title: Text(widget.title), ), body: Center( child: RaisedButton( onPressed: () { snackBar.SnackBarByKey(scaffoldKey, context, "Test"); // print("Tap"); // Scaffold.of(context) // .showSnackBar(new SnackBar(content: Text('Test'))); }, child: new Container( padding: new EdgeInsets.all(12.0), child: new Text('Flat Button'), ), )), ); } } |
这样就可以了，就是增加了第2、28、33、40行的代码而已，效果如下。
为啥这dart的自动格式化是2空格的缩进，异端啊….
我在stackoverflow上走到一个方案，就是搞一个globalKey，是可以正常使用的