| // Copyright 2014 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Template: dev/snippets/config/templates/stateful_widget_scaffold_center.tmpl |
| // |
| // Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring |
| // of samples, and may be ignored if you are just exploring the sample. |
| |
| // Flutter code sample for DropdownButton |
| // |
| //*************************************************************************** |
| //* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker) |
| |
| // This sample shows a `DropdownButton` with a large arrow icon, |
| // purple text style, and bold purple underline, whose value is one of "One", |
| // "Two", "Free", or "Four". |
| // |
| // ![](https://flutter.github.io/assets-for-api-docs/assets/material/dropdown_button.png) |
| |
| //* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker) |
| //*************************************************************************** |
| |
| import 'package:flutter/material.dart'; |
| |
| void main() => runApp(const MyApp()); |
| |
| /// This is the main application widget. |
| class MyApp extends StatelessWidget { |
| const MyApp({Key? key}) : super(key: key); |
| |
| static const String _title = 'Flutter Code Sample'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return MaterialApp( |
| title: _title, |
| home: Scaffold( |
| appBar: AppBar(title: const Text(_title)), |
| body: const Center( |
| child: MyStatefulWidget(), |
| ), |
| ), |
| ); |
| } |
| } |
| |
| /// This is the stateful widget that the main application instantiates. |
| class MyStatefulWidget extends StatefulWidget { |
| const MyStatefulWidget({Key? key}) : super(key: key); |
| |
| @override |
| State<MyStatefulWidget> createState() => _MyStatefulWidgetState(); |
| } |
| |
| /// This is the private State class that goes with MyStatefulWidget. |
| class _MyStatefulWidgetState extends State<MyStatefulWidget> { |
| //******************************************************************** |
| //* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker) |
| |
| String dropdownValue = 'One'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return DropdownButton<String>( |
| value: dropdownValue, |
| icon: const Icon(Icons.arrow_downward), |
| iconSize: 24, |
| elevation: 16, |
| style: const TextStyle(color: Colors.deepPurple), |
| underline: Container( |
| height: 2, |
| color: Colors.deepPurpleAccent, |
| ), |
| onChanged: (String? newValue) { |
| setState(() { |
| dropdownValue = newValue!; |
| }); |
| }, |
| items: <String>['One', 'Two', 'Free', 'Four'] |
| .map<DropdownMenuItem<String>>((String value) { |
| return DropdownMenuItem<String>( |
| value: value, |
| child: Text(value), |
| ); |
| }).toList(), |
| ); |
| } |
| |
| //* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker) |
| //******************************************************************** |
| |
| } |