TextFormField 验证器参数类型“动态函数（）”不能分配给

Question

我正在尝试制作自定义小部件 TextFormField， 但是验证器：验证器，显示错误

参数类型“动态函数（）”不能分配给参数类型“字符串？函数（字符串？）？'.dartargument_type_not_assignable 动态 Function() 验证器 包：store/widgets/mytextformfield.dart

mytextformfield.dart

导入'package:flutter/material.dart';

class MyTextFormField extends StatelessWidget {
  final Function() validator;
  final bool obserText;
  final String name;

  const MyTextFormField({
    Key? key,
    required this.obserText,
    required this.validator,
    required this.name,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return TextFormField(
      obscureText: obserText,
      **validator: validator,**
      decoration: InputDecoration(
        border: const OutlineInputBorder(),
        hintText: name,
      ),
    );
  }
}

在 login.dart 上

MyTextFormField(
      obserText: obserText,
      name: "Email",
          validator: (value) {
          if (value == "") {
         return "Please Fill Email";
        } else if (!regExp.hasMatch(value!)) {
          return "Email is Invaild";
        }
      return "";
      },
     ),

Answer 1

验证器必须有参数，如果值没有任何错误则返回null，如果值无效则返回一个String表示错误。

     TextFormField(
        // The validator receives the text that the user has entered.
        validator: (value) {
          if (value == null || value.isEmpty) {
            return 'Please enter some text';
          }
          return null;
        },
      ),