void main() 
  runApp(
    MaterialApp(
      home: Container(
          color: Colors.white,
          child:Row(
            children:const <Widget>[
              Icon(
                Icons.favorite,
                color: Colors.pink,
                size: 24.0,
                semanticLabel: 'Text to announce in accessibility modes',
              ),
              Icon(
                Icons.audiotrack,
                color: Colors.green,
                size: 30.0,
              ),
              Icon(
                Icons.beach_access,
                color: Colors.blue,
                size: 36.0,
              ),
            ],
  )
  ),
    ),
  );

运行效果

2.1 Icon种类

IconButton，用于交互式图标。
Icons，用于此类的可用图标列表(这个是不可以交互的图标)。
IconTheme，为图标提供环境配置。
ImageIcon，用于显示来自 AssetImages 或其他 ImageProvider 的图标。

2.2 基本属性

color
- 类型：Color
- 说明：图标颜色
icon
- 类型：IconData
- 说明：显示的图标
semanticLabel
- 类型：String
- 说明：语义标签，此标签不会显示在UI中
size
- 类型：double
- 说明：图标尺寸
textDirection
- 类型：TextDirection
- 说明：用户呈现图标的文本方向

2.3 Icon举例

下面👇这个示例展示了IconButton使用 Material icon “volume_up”来增加音量

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(),
        ),
      ),
    );
  


double _volume = 0.0;

/// 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> 
  @override
  Widget build(BuildContext context) 
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: <Widget>[
        IconButton(
          icon: const Icon(Icons.volume_up),
          tooltip: 'Increase volume by 10',
          onPressed: () 
            setState(() 
              _volume += 10;
            );
          ,
        ),
        Text('Volume : $_volume')
      ],
    );