我基于 initStat 函式中的字串項串列創建了 RadioListTile。但是當它被選中時，我無法更改單選按鈕。如果它在構建函式中，我可以呼叫 setState 并將其標記為選中。當我在代碼開頭創建它時，如何將其標記為已選中。下面是我嘗試過的代碼，它實際上列印了選定的 radioTile 值，但我無法讓它更改選定狀態或單選按鈕選擇。
List<String> list = ['Satisfied', 'Not Satisfied', 'Very Satisfied','Neutral'];
String _radioGroupValue = '';
int selectedRadioTile = 0;
void initState() {
super.initState();
selectedRadioTile = 0;
setState(() {
for (int n = 0; n < list.length; n ) {
answersRadio.add(RadioListTile(
value: n,
groupValue: _radioGroupValue,
onChanged: (val) {
print('selected Radio index $val');
setSelectedRadioTile(val);
setState(() {
});
},
title: Text(list[n]),
selected: _radioGroupValue == list[n] ? true : false,
));
}
});
}
setSelectedRadioTile(int val){
setState(() {
selectedRadioTile = val;
});
}
child: Column(children: answersRadio,)
uj5u.com熱心網友回復：
class Example extends StatefulWidget {
const Example({Key? key}) : super(key: key);
@override
State<StatefulWidget> createState() {
return _Examplestate();
}
}
class _Examplestate extends State<Example> {
List<String> list = [
'Satisfied',
'Not Satisfied',
'Very Satisfied',
'Neutral'
];
String? _radioGroupValue;
List<RadioListTile> answersRadio = [];
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Stateful Widget'),
),
body: Column(
children: [
for (var n in list)
RadioListTile<String>(
value: n,
groupValue: _radioGroupValue,
onChanged: (val) {
_radioGroupValue = val;
setState(() {});
},
title: Text(n),
toggleable: true,
selected: _radioGroupValue == n,
)
],
),
);
}
}
uj5u.com熱心網友回復：
設定int _groupValue = -1。value :根據您的需要定義引數的值
Radio(
materialTapTargetSize:
MaterialTapTargetSize.shrinkWrap,
visualDensity: VisualDensity.comfortable,
activeColor: AppTheme.primaryColor,
value: 1,
groupValue: _groupValue,
onChanged: (value) {
setState(() {
_groupValue = value as int;
});
},
),
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