Flutter Widget之Icon

Widget：https://flutter.io/docs/development/ui/widgets
Icon：https://docs.flutter.io/flutter/widgets/Icon-class.html

import 'package:flutter/material.dart';

class IconDemoPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => new _IconDemoPagePageState();
}

class _IconDemoPagePageState extends State<IconDemoPage> {
  double _volume = 0.0;

  @override
  void initState() {
    super.initState();
  }

  Widget build(BuildContext context) {
    return Scaffold(
        appBar: new AppBar(
          title: new Text('Icon Demo'),
        ),
        body: SingleChildScrollView(
            child: Column(
              children: <Widget>[
                // IconButton
                IconButton(
                  icon: Icon(Icons.volume_up),
                  tooltip: 'Increase volume by 10%',
                  onPressed: () {
                    setState(() {
                      _volume *= 1.1;
                    });
                  },
                ),
                // IconTheme
                // ImageIcon
              ],
            )
        )
    );
  }
}