Flutter：自定义单选按钮

这是完整的代码

class CustomRadio extends StatefulWidget {  @override  createState() {    return new CustomRadioState();  }}class CustomRadioState extends State<CustomRadio> {  List<RadioModel> sampleData = new List<RadioModel>();  @override  void initState() {    // TODO: implement initState    super.initState();    sampleData.add(new RadioModel(false, 'A', 'April 18'));    sampleData.add(new RadioModel(false, 'B', 'April 17'));    sampleData.add(new RadioModel(false, 'C', 'April 16'));    sampleData.add(new RadioModel(false, 'D', 'April 15'));  }  @override  Widget build(BuildContext context) {    return new Scaffold(      appBar: new AppBar(        title: new Text("ListItem"),      ),      body: new ListView.builder(        itemCount: sampleData.length,        itemBuilder: (BuildContext context, int index) {          return new InkWell( //highlightColor: Colors.red, splashColor: Colors.blueAccent, onTap: () {   setState(() {     sampleData.forEach((element) => element.isSelected = false);     sampleData[index].isSelected = true;   }); }, child: new RadioItem(sampleData[index]),          );        },      ),    );  }}class RadioItem extends StatelessWidget {  final RadioModel _item;  RadioItem(this._item);  @override  Widget build(BuildContext context) {    return new Container(      margin: new EdgeInsets.all(15.0),      child: new Row(        mainAxisSize: MainAxisSize.max,        children: <Widget>[          new Container( height: 50.0, width: 50.0, child: new Center(   child: new Text(_item.buttonText,       style: new TextStyle(color:    _item.isSelected ? Colors.white : Colors.black,//fontWeight: FontWeight.bold,fontSize: 18.0)), ), decoration: new BoxDecoration(   color: _item.isSelected       ? Colors.blueAccent       : Colors.transparent,   border: new Border.all(       width: 1.0,       color: _item.isSelected? Colors.blueAccent: Colors.grey),   borderRadius: const BorderRadius.all(const Radius.circular(2.0)), ),          ),          new Container( margin: new EdgeInsets.only(left: 10.0), child: new Text(_item.text),          )        ],      ),    );  }}class RadioModel {  bool isSelected;  final String buttonText;  final String text;  RadioModel(this.isSelected, this.buttonText, this.text);}

To use :

void main() {  runApp(new MaterialApp(    home: new CustomRadio(),  ));}