/* //导入cupertino widget 库 import 'package:flutter/cupertino.dart'; void main() { runApp(const CupertinoTestRoute()); } class CupertinoTestRoute extends StatelessWidget { const CupertinoTestRoute({Key? key}) : super(key: key); @override Widget build(BuildContext context) { return CupertinoPageScaffold( navigationBar: const CupertinoNavigationBar( middle: Text("Cupertino Demo"), ), child: Center( child: CupertinoButton( color: CupertinoColors.activeBlue, child: const Text("Press"), onPressed: () {} ), ), ); } } */ import 'package:english_words/english_words.dart'; import 'package:flutter/material.dart'; void main() { runApp(const MyApp()); } class MyApp extends StatelessWidget { const MyApp({super.key}); // This widget is the root of your application. @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( // This is the theme of your application. // // TRY THIS: Try running your application with "flutter run". You'll see // the application has a blue toolbar. Then, without quitting the app, // try changing the seedColor in the colorScheme below to Colors.green // and then invoke "hot reload" (save your changes or press the "hot // reload" button in a Flutter-supported IDE, or press "r" if you used // the command line to start the app). // // Notice that the counter didn't reset back to zero; the application // state is not lost during the reload. To reset the state, use hot // restart instead. // // This works for code too, not just values: Most code changes can be // tested with just a hot reload. colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple), useMaterial3: true, ), home: const MyHomePage(title: 'Flutter Demo Home Page'), // home: const CounterWidget(), // home: const GetStateObjectRoute(), ); } } class MyHomePage extends StatefulWidget { const MyHomePage({super.key, required this.title}); // This widget is the home page of your application. It is stateful, meaning // that it has a State object (defined below) that contains fields that affect // how it looks. // This class is the configuration for the state. It holds the values (in this // case the title) provided by the parent (in this case the App widget) and // used by the build method of the State. Fields in a Widget subclass are // always marked "final". final String title; @override State createState() => _MyHomePageState(); } class _MyHomePageState extends State { int _counter = 0; void _incrementCounter() { setState(() { // This call to setState tells the Flutter framework that something has // changed in this State, which causes it to rerun the build method below // so that the display can reflect the updated values. If we changed // _counter without calling setState(), then the build method would not be // called again, and so nothing would appear to happen. _counter++; }); //导航到新路由 Navigator.push( context, MaterialPageRoute(builder: (context) { return NewRoute(); }), ); } @override Widget build(BuildContext context) { // This method is rerun every time setState is called, for instance as done // by the _incrementCounter method above. // // The Flutter framework has been optimized to make rerunning build methods // fast, so that you can just rebuild anything that needs updating rather // than having to individually change instances of widgets. return Scaffold( appBar: AppBar( // TRY THIS: Try changing the color here to a specific color (to // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar // change color while the other colors stay the same. backgroundColor: Theme.of(context).colorScheme.inversePrimary, // Here we take the value from the MyHomePage object that was created by // the App.build method, and use it to set our appbar title. title: Text(widget.title), ), body: Center( // Center is a layout widget. It takes a single child and positions it // in the middle of the parent. // child: Column( // // Column is also a layout widget. It takes a list of children and // // arranges them vertically. By default, it sizes itself to fit its // // children horizontally, and tries to be as tall as its parent. // // // // Column has various properties to control how it sizes itself and // // how it positions its children. Here we use mainAxisAlignment to // // center the children vertically; the main axis here is the vertical // // axis because Columns are vertical (the cross axis would be // // horizontal). // // // // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint" // // action in the IDE, or press "p" in the console), to see the // // wireframe for each widget. // mainAxisAlignment: MainAxisAlignment.center, // children: [ // const Text( // 'You have pushed the button this many times:', // ), // Text( // '$_counter', // style: Theme.of(context).textTheme.headlineMedium, // ), // ], // ), child: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ RandomWordsWidget(), ], ), ), floatingActionButton: FloatingActionButton( onPressed: _incrementCounter, tooltip: 'Increment', child: const Icon(Icons.add), ), // This trailing comma makes auto-formatting nicer for build methods. ); } } // 测试无状态工具描述ui class Echo extends StatelessWidget { const Echo({ Key? key, required this.text, this.backgroundColor = Colors.grey, //默认为灰色 }) : super(key: key); final String text; final Color backgroundColor; @override Widget build(BuildContext context) { return Center( child: Container( color: backgroundColor, child: Text(text), ), ); } } // 测试State状态生命周期 class CounterWidget extends StatefulWidget { const CounterWidget({Key? key, this.initValue = 0}); final int initValue; @override _CounterWidgetState createState() => _CounterWidgetState(); } class _CounterWidgetState extends State { int _counter = 0; @override void initState() { super.initState(); //初始化状态 _counter = widget.initValue; print("initState"); } @override Widget build(BuildContext context) { print("build"); return Scaffold( body: Center( child: TextButton( child: Text('$_counter'), //点击后计数器自增 onPressed: () => setState( () => ++_counter, ), ), ), ); } @override void didUpdateWidget(CounterWidget oldWidget) { super.didUpdateWidget(oldWidget); print("didUpdateWidget "); } @override void deactivate() { super.deactivate(); print("deactivate"); } @override void dispose() { super.dispose(); print("dispose"); } @override void reassemble() { super.reassemble(); print("reassemble"); } @override void didChangeDependencies() { super.didChangeDependencies(); print("didChangeDependencies"); } } //在 widget 树中获取State对象 class GetStateObjectRoute extends StatefulWidget { const GetStateObjectRoute({Key? key}) : super(key: key); @override State createState() => _GetStateObjectRouteState(); } class _GetStateObjectRouteState extends State { @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text("子树中获取State对象"), ), body: Center( child: Column( children: [ Builder(builder: (context) { return ElevatedButton( onPressed: () { // // 查找父级最近的Scaffold对应的ScaffoldState对象 // ScaffoldState _state = context.findAncestorStateOfType()!; // // 打开抽屉菜单 // _state.openDrawer(); // // 直接通过of静态方法来获取ScaffoldState // ScaffoldState _state=Scaffold.of(context); // // 打开抽屉菜单 // _state.openDrawer(); ScaffoldMessenger.of(context).showSnackBar( SnackBar(content: Text("我是SnackBar")), ); }, child: Text('打开抽屉菜单1'), ); }), ], ), ), drawer: Drawer(), ); } } // 路由管理,就是页面跳转 class NewRoute extends StatelessWidget { @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text("New route"), ), body: Center( child: Text("This is new route"), ), ); } } class RandomWordsWidget extends StatelessWidget { @override Widget build(BuildContext context) { // 生成随机字符串 final wordPair = WordPair.random(); return Padding( padding: const EdgeInsets.all(8.0), child: Text(wordPair.toString()), ); } }