HarmonyOS一杯冰美式的时间 -- 验证码框，flutter跳转页面

在HarmonyOS上使用Flutter开发应用时，如果需要实现验证码输入框、跳转页面等功能，可以参考以下代码示例：

import 'package:flutter/material.dart';
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: VerificationBoxPage(),
    );
  }
}
 
class VerificationBoxPage extends StatefulWidget {
  @override
  _VerificationBoxPageState createState() => _VerificationBoxPageState();
}
 
class _VerificationBoxPageState extends State<VerificationBoxPage> {
  final FocusNode _focusNode = FocusNode();
  final List<TextEditingController> _controllers = [];
  final _formKey = GlobalKey<FormState>();
 
  @override
  void initState() {
    super.initState();
    // 初始化验证码输入框控制器
    for (int i = 0; i < 4; i++) {
      _controllers.add(TextEditingController());
    }
  }
 
  @override
  void dispose() {
    _focusNode.dispose();
    for (var controller in _controllers) {
      controller.dispose();
    }
    super.dispose();
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('验证码框示例'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: Column(
            children: <Widget>[
              for (int i = 0; i < 4; i++)
                Expanded(
                  child: TextFormField(
                    controller: _controllers[i],
                    textAlign: TextAlign.center,
                    keyboardType: TextInputType.number,
                    decoration: InputDecoration(
                      border: OutlineInputBorder(),
                      hintText: i == 3 ? '请输入验证码' : '',
                    ),
                    validator: (value) {
                      if (value.isEmpty) {
                        return '请输入验证码';
                      }
                      return null;
                    },
                    onFieldSubmitted: (value) {
                      if (i == 3) {
                        // 最后一个验证码输入完成后，提交表单
                        _submit();
                      } else {
                        // 切换到下一个