1. // Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
2. // for details. All rights reserved. Use of this source code is governed by a
3. // BSD-style license that can be found in the LICENSE file.
4.  
5. import 'package:flutter/material.dart';
6.  
7. void main() {
8.   runApp(MyApp());
9. }
10.  
11. class MyApp extends StatelessWidget {
12.   @override
13.   Widget build(BuildContext context) {
14.     return MaterialApp(
15.       title: 'my app',
16.       debugShowCheckedModeBanner: false,
17.       theme: ThemeData(
18.         colorScheme: ColorScheme.fromSeed(seedColor: Colors.red),
19.         useMaterial3: true,
20.       ),
21.       home: MainPage(),
22.     );
23.   }
24. }
25.  
26.  
27. class MainPage extends StatefulWidget {
28.   State<MainPage> createState() => _MainPage();
29. }
30.  
31. class _MainPage extends State<MainPage> {
32.   String value = "";
33.   Widget build(BuildContext context) {
34.     return Scaffold(
35.       body: ElevatedButton(
36.         onPressed: () {
37.           print("Hello");
38.         },
39.         child: Text("Click me"),
40.       ),
41.     );
42.   }
43. }
44.  
45.  
46.  
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48.  
49.  
50.  
51.  
52.  
53.  
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55.  
56.  
57.  
58.  
59.  
60.  
61. class MyHomePage extends StatefulWidget {
62.   final String title;
63.  
64.   const MyHomePage({
65.     Key? key,
66.     required this.title,
67.   }) : super(key: key);
68.  
69.   @override
70.   State<MyHomePage> createState() => _MyHomePageState();
71. }
72.  
73. class _MyHomePageState extends State<MyHomePage> {
74.   int _counter = 0;
75.  
76.   void _incrementCounter() {
77.     setState(() {
78.       _counter++;
79.     });
80.   }
81.  
82.   @override
83.   Widget build(BuildContext context) {
84.     return Scaffold(
85.       appBar: AppBar(
86.         backgroundColor: Theme.of(context).colorScheme.inversePrimary,
87.         title: Text(widget.title),
88.       ),
89.       body: Center(
90.         child: Column(
91.           mainAxisAlignment: MainAxisAlignment.center,
92.           children: [
93.             const Text(
94.               'You have pushed the button this many times:',
95.             ),
96.             Text(
97.               '$_counter',
98.               style: Theme.of(context).textTheme.headlineMedium,
99.             ),
100.           ],
101.         ),
102.       ),
103.       floatingActionButton: FloatingActionButton(
104.         onPressed: _incrementCounter,
105.         tooltip: 'Increment',
106.         child: const Icon(Icons.add),
107.       ),
108.     );
109.   }
110. }