Flutter添加TextFormField时位置参数相关报错如何解决

错误原因 #

• Padding组件仅支持接收1个child参数，你的代码中在Text组件后直接将SizedBox作为第二个参数传入Padding，违反了参数传递规则，直接触发「位置参数必须在命名参数之前」「位置参数过多」报错
• 笔误问题：Flutter内置组件名是大驼峰写法，你写的小写sizedBox是错误的，正确写法为SizedBox

修复方案 #

将Padding的child替换为Column组件，把文本、间隔、TextFormField按顺序放入Column的子组件列表即可，修改后的完整代码如下：

import 'package:flutter/material.dart';

class ForgotPassword extends StatefulWidget {
  const ForgotPassword({Key? key}) : super(key: key);

  @override
  _ForgotPasswordState createState() => _ForgotPasswordState();
}

class _ForgotPasswordState extends State<ForgotPassword> {
  // 用来控制输入框内容的控制器
  final TextEditingController _emailController = TextEditingController();

  @override
  void dispose() {
    // 页面销毁时释放控制器，避免内存泄漏
    _emailController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(onPressed: () {}, icon: const Icon(Icons.exit_to_app)),
      ),
      body: SingleChildScrollView(
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            children: <Widget>[
              Padding(
                padding: const EdgeInsets.symmetric(
                  vertical: 35.0,
                ),
                child: const Text(
                  'Forgot Password',
                  style: TextStyle(
                      color: Colors.blue,
                      fontWeight: FontWeight.bold,
                      fontSize: 20.0),
                ),
              ),
              Padding(
                padding: const EdgeInsets.fromLTRB(0, 12, 0, 0),
                child: Container(
                  child: Image.asset('assets/forgot password 1.png'),
                ),
              ),
              Container(
                height: 440.0,
                color: Colors.transparent,
                child: Container(
                  decoration: BoxDecoration(
                      color: Colors.blue,
                      borderRadius: const BorderRadius.only(
                        topLeft: Radius.circular(40.0),
                        topRight: Radius.circular(40.0),
                      )),
                  child: Align(
                    alignment: Alignment.topCenter,
                    child: Padding(
                      padding: const EdgeInsets.symmetric(vertical: 40, horizontal: 24),
                      // 这里替换为Column承载多个子组件
                      child: Column(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          const Text(
                            'Masukkan Email',
                            style: TextStyle(
                                color: Colors.white,
                                fontSize: 14,
                                fontWeight: FontWeight.bold),
                          ),
                          const SizedBox(height: 20,),
                          // 新增的TextFormField，已适配蓝色背景的样式
                          TextFormField(
                            controller: _emailController,
                            keyboardType: TextInputType.emailAddress,
                            style: const TextStyle(color: Colors.black87),
                            decoration: InputDecoration(
                              filled: true,
                              fillColor: Colors.white,
                              hintText: 'Contoh: email@gmail.com',
                              contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
                              border: OutlineInputBorder(
                                borderRadius: BorderRadius.circular(12),
                                borderSide: BorderSide.none
                              )
                            ),
                          )
                        ],
                      ),
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

内容的提问来源于stack exchange，提问作者Imam Rizky GANTENG