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- import 'package:flutter/material.dart';
-
- void main() {
- runApp(MyApp());
- }
-
- class MyApp extends StatelessWidget {
- // 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 running your application with "flutter run". You'll see the
- // application has a blue toolbar. Then, without quitting the app, try
- // changing the primarySwatch below to Colors.green and then invoke
- // "hot reload" (press "r" in the console where you ran "flutter run",
- // or simply save your changes to "hot reload" in a Flutter IDE).
- // Notice that the counter didn't reset back to zero; the application
- // is not restarted.
- primarySwatch: Colors.blue,
- // This makes the visual density adapt to the platform that you run
- // the app on. For desktop platforms, the controls will be smaller and
- // closer together (more dense) than on mobile platforms.
- visualDensity: VisualDensity.adaptivePlatformDensity,
- ),
- home: MyHomePage(title: 'Flutter Demo Home Page'),
- );
- }
- }
-
- class MyHomePage extends StatefulWidget {
- MyHomePage({Key key, this.title}) : super(key: key);
-
- // 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
- _MyHomePageState createState() => _MyHomePageState();
- }
-
- class _MyHomePageState extends State<MyHomePage> {
- 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++;
- });
- }
-
- @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(
- // 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.
- //
- // Invoke "debug painting" (press "p" in the console, choose the
- // "Toggle Debug Paint" action from the Flutter Inspector in Android
- // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
- // to see the wireframe for each widget.
- //
- // 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).
- mainAxisAlignment: MainAxisAlignment.center,
- children: <Widget>[
- Text(
- 'You have pushed the button this many times:',
- ),
- Text(
- '$_counter',
- style: Theme.of(context).textTheme.headline4,
- ),
- ],
- ),
- ),
- floatingActionButton: FloatingActionButton(
- onPressed: _incrementCounter,
- tooltip: 'Increment',
- child: Icon(Icons.add),
- ), // This trailing comma makes auto-formatting nicer for build methods.
- );
- }
- }
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