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Accepted
Victor Woode
Asked: 2024-11-17 05:39:30 +0800 CST

Flutter textField 自动设置状态

  • 772

RadioListTile我在 中有一个列表DraggableScrollabeSheet。当我点击其中一个 RadioListTile 时，会出现一个 TextField。但我一点击该文本字段，就收到一个 SetState 响应，选项返回到选项 1。所以我无法在 TextField 中输入任何内容。

List<String> options1 = [
      "A",
      "B",
      "C",
      "D",
      "Others"
     ...
    ];
    String currentOption = options[0];

Column(
  children:[
     RadioListTile(
      activeColor: Colors.red,
      title: Text("A"),
      value: options[0],
      groupValue: currentOption,
      onChanged: (value){
          setState((){
           currentOption = value.toString();
         })
        }
      )
.....//This continues till the last option

     //Then if the last option (Other) is chosen, a textfield is displayed
     
    currentOption == options[4]?
     TextField(
         .....
         ):SizedBox(),

     ]
   )

因此，当我点击文本字段时，它会设置状态，并且当前选项会移回options[0]

flutter

1 个回答

  1. Best Answer

    发生这种情况是因为您在build方法内声明了变量，每次您尝试更新 UI 时（当您调用时setState）都会重置变量值

    您可以在此处执行的操作是初始化变量，initState这将解决您的问题

    下面是一个示例：

    class SheetView extends StatefulWidget {
  const SheetView({
    super.key,
  });

  @override
  State<SheetView> createState() => _SheetViewState();
}

class _SheetViewState extends State<SheetView> {
  late String currentOption;
  List<String> options1 = [
      "A",
      "B",
      "C",
      "D",
      "Others"
    ];

@override
void initState() {
/// This will be called before UI is created
currentOption = options[0];
    super.initState();
}

  @override
  Widget build(BuildContext context) {
    return Column(
  children:[
     RadioListTile(
      activeColor: Colors.red,
      title: Text("A"),
      value: options[0],
      groupValue: currentOption,
      onChanged: (value){
          setState((){
           currentOption = value.toString();
         })
        }
      ),

     //This continues till the last option
     //Then if the last option (Other) is chosen, a textfield is displayed
     
    currentOption == options[4] ?
     TextField(
         .....
         ) : SizedBox(),
     ]
   );
  }
}
    • 1

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