Android 设置状态不'；不要改变TextField的装饰

当OnSubmited方法调用时，我想更改TextField的修饰，在setState中，当我调用返回InputDecoration的函数时，它不会更改TextField的修饰

class CustomTextField extends StatefulWidget {
  final TextEditingController controller;
  final IconData icon;
  final String textLabel;
  final TextInputType textInputType;
  CustomTextField(
      this.controller, this.icon, this.textLabel, this.textInputType);
  @override
  _CustomTextFieldState createState() => _CustomTextFieldState();

}

class _CustomTextFieldState extends State<CustomTextField> {
  InputDecoration inputDecoration;
  double a = 0;
  bool b = true;
  @override
  Widget build(BuildContext context) {
    inputDecoration = noramlInputDecoration(context, widget.textLabel, Icon(widget.icon));
    return Container(
      margin: EdgeInsets.only(top: responsiveHeight(context, 0.8)),
      child: TextField(
        onSubmitted: (mahdi) {
          print('adfaf');
          setState(() {
            inputDecoration = noramlInputDecoration(
                context, widget.textLabel, Icon(widget.icon));
          });
          a++;
          print(a);
        },
        decoration: inputDecoration,
        onTap: () {},
        toolbarOptions: ToolbarOptions(
          paste: true,
          copy: true,
          cut: true,
          selectAll: true,
        ),
        cursorWidth: 2,
        style: TextStyle(
            fontSize: responsiveWidthGivenWidth(
                responsiveWidth(context, 81.6) / 10, 53.3),
            height: 0.5),
        controller: widget.controller,
        maxLines: 1,
        obscureText: b,
        showCursor: true,
        textAlign: TextAlign.end,
        textDirection: TextDirection.ltr,
        keyboardType: widget.textInputType,
        inputFormatters: [],
      ),
    );
  }
}

实际上，我想检查用户是否正确填写文本字段，如果没有，则通过更改文本字段的装饰来警告他们

class CustomTextField extends StatefulWidget {
  final TextEditingController controller;
  final IconData icon;
  final String textLabel;
  final TextInputType textInputType;
  CustomTextField(
      this.controller, this.icon, this.textLabel, this.textInputType);
  @override
  _CustomTextFieldState createState() => _CustomTextFieldState();

}

class _CustomTextFieldState extends State<CustomTextField> {
  InputDecoration inputDecoration;
  double a = 0;
  bool b = true;
  @override
  Widget build(BuildContext context) {
    inputDecoration = noramlInputDecoration(context, widget.textLabel, Icon(widget.icon));
    return Container(
      margin: EdgeInsets.only(top: responsiveHeight(context, 0.8)),
      child: TextField(
        onSubmitted: (mahdi) {
          print('adfaf');
          setState(() {
            inputDecoration = noramlInputDecoration(
                context, widget.textLabel, Icon(widget.icon));
          });
          a++;
          print(a);
        },
        decoration: inputDecoration,
        onTap: () {},
        toolbarOptions: ToolbarOptions(
          paste: true,
          copy: true,
          cut: true,
          selectAll: true,
        ),
        cursorWidth: 2,
        style: TextStyle(
            fontSize: responsiveWidthGivenWidth(
                responsiveWidth(context, 81.6) / 10, 53.3),
            height: 0.5),
        controller: widget.controller,
        maxLines: 1,
        obscureText: b,
        showCursor: true,
        textAlign: TextAlign.end,
        textDirection: TextDirection.ltr,
        keyboardType: widget.textInputType,
        inputFormatters: [],
      ),
    );
  }
}

---

正如@Ryosuke在问题的评论中所说，我不应该在build方法中使用setState（），因为每次调用setState（）时，它都卡在循环中，总是调用build（）方法。

setState（）

调用build方法。因此，您在

setState

内部分配给

inputDecoration

的值将被您在

build

的第一行中分配给它的值覆盖。因此，请尝试将您的初始

inputDecoration

作业从

build

移动到

build

之外的某个地方，最好是在

initState

内部。哦，我现在明白了，我照您说的做，现在就可以了。非常感谢。