flutter单选按钮radio

class RadioDemo extends StatefulWidget {
  @override
  _RadioDemoState createState() => _RadioDemoState();
}

class _RadioDemoState extends State<RadioDemo> {
  int _radioGroupA = 0;

  void _handleRadioValueChanged(int value) {
    setState(() {
      _radioGroupA = value;
    });
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Radio'), elevation: 0.0,),
      body: Container(
        padding: EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('选择结果是：第$_radioGroupA个'),
            // 带图标和标签的单选
            RadioListTile(
              value: 0,
              groupValue: _radioGroupA,
              onChanged: _handleRadioValueChanged,
              title: Text('选项一'),
              subtitle: Text('这是选项一'),
              secondary: Icon(Icons.filter_1),
              selected: _radioGroupA == 0,
            ),
            RadioListTile(
              value: 1,
              groupValue: _radioGroupA,
              onChanged: _handleRadioValueChanged,
              title: Text('选项二'),
              subtitle: Text('这是选项二'),
              secondary: Icon(Icons.filter_1),
              selected: _radioGroupA == 1,
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                Radio(
                  value: 0,
                  groupValue: _radioGroupA,
                  onChanged: _handleRadioValueChanged,
                  activeColor: Colors.blue,
                ),
                Radio(
                  value: 1,
                  groupValue: _radioGroupA,
                  onChanged: _handleRadioValueChanged,
                  activeColor: Colors.blue,
                ),
              ],
            )
          ],
        ),
      ),
    );
  }
}