flutter Radio单选框

import 'package:flutter/material.dart';
class RadioDemo extendsStatefulWidget {
  @override
  _RadioDemoState createState() =>_RadioDemoState();
}
class _RadioDemoState extends State<RadioDemo>{
  int _radioGroupA = 0;
  void _handleRadioValueChanged(intvalue) {
    setState(() {
      _radioGroupA =value;
    });
  }
  @override
  Widget build(BuildContext context) {
    returnScaffold(
      appBar: AppBar(
        title: Text('RadioDemo'),
        elevation: 0.0,
      ),
      body: Container(
        padding: EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('RadioGroupValue: $_radioGroupA'),
            SizedBox(height: 32.0),
            RadioListTile(
              value: 0,
              groupValue: _radioGroupA,
              onChanged: _handleRadioValueChanged,
              title: Text('Options A'),
              subtitle: Text('Description'),
              secondary: Icon(Icons.filter_1),
              selected: _radioGroupA == 0,
            ),
            RadioListTile(
              value: 1,
              groupValue: _radioGroupA,
              onChanged: _handleRadioValueChanged,
              title: Text('Options B'),
              subtitle: Text('Description'),
              secondary: Icon(Icons.filter_2),
              selected: _radioGroupA == 1,
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                //Radio(
                //value: 0,
                //groupValue: _radioGroupA,
                //onChanged: _handleRadioValueChanged,
                //activeColor: Colors.black,
                //),
                //Radio(
                //value: 1,
                //groupValue: _radioGroupA,
                //onChanged: _handleRadioValueChanged,
                //activeColor: Colors.black,
                //),
],
            ),
          ],
        ),
      )
    );
  }
}