标签:als page welcome appbar body oid assign let caff
在显示SimpleDialog时候程序报错 No MaterialLocalizations found 没有找到 MaterialLocalizations
搜索找到原因 runApp 需要先调用 StatelessWidget 返回一个 MaterialApp实例.
void main() => runApp(MainPage()); class MainPage extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: ‘Welcome to Flutter‘, debugShowCheckedModeBanner: false, home: HomePage(), ); } }
也就是说runApp 直接接受一个 StatefulWidget就会出现这个错误
完整代码
import ‘package:flutter/material.dart‘; void main() => runApp(MainPage()); class MainPage extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: ‘Welcome to Flutter‘, debugShowCheckedModeBanner: false, home: HomePage(), ); } } class HomePage extends StatefulWidget { @override _HomePage createState() { return _HomePage(title: ‘简单对话框组件‘); } } enum Department { treasury, state } class _HomePage extends State<HomePage> { _HomePage({Key key, @required this.title}); final String title; ThemeData themeData = new ThemeData.light(); Future<void> _askedToLead() async { switch (await showDialog<Department>( context: context, builder: (BuildContext context) { return SimpleDialog( title: const Text(‘Select assignment‘), children: <Widget>[ SimpleDialogOption( onPressed: () { Navigator.pop(context, Department.treasury); }, child: const Text(‘Treasury department‘), ), SimpleDialogOption( onPressed: () { Navigator.pop(context, Department.state); }, child: const Text(‘State department‘), ), ], ); })) { case Department.treasury: // Let‘s go. // ... break; case Department.state: // ... break; } } @override Widget build(BuildContext context) { return new MaterialApp( title: this.title, debugShowCheckedModeBanner: false, home: new Scaffold( appBar: new AppBar( title: new Text(this.title), ), body: null, floatingActionButton: FloatingActionButton( child: Icon(Icons.format_list_numbered), onPressed: _askedToLead, ), ), theme: themeData, ); } }
No MaterialLocalizations found (Flutter)
标签:als page welcome appbar body oid assign let caff
原文地址:https://www.cnblogs.com/z45281625/p/10469978.html