307 lines
9.0 KiB
Dart
307 lines
9.0 KiB
Dart
// 班级码加入页面 — 学生/家长通过 6 位码加入班级
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//
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// 设计要点：
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// - 6 位独立输入框，自动聚焦下一位
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// - 输入完成后自动提交验证
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// - 安全限制：5 次错误后锁定 30 分钟
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// - 友好的状态反馈（验证中/成功/失败）
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import 'package:flutter/material.dart';
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import 'package:flutter_bloc/flutter_bloc.dart';
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import 'package:go_router/go_router.dart';
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import '../../../core/constants/design_tokens.dart';
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import '../bloc/auth_bloc.dart';
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/// 班级码加入页面
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class ClassCodeJoinPage extends StatefulWidget {
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const ClassCodeJoinPage({super.key});
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@override
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State<ClassCodeJoinPage> createState() => _ClassCodeJoinPageState();
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}
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class _ClassCodeJoinPageState extends State<ClassCodeJoinPage> {
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final List<TextEditingController> _controllers = List.generate(
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DesignTokens.classCodeLength,
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(_) => TextEditingController(),
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);
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final List<FocusNode> _focusNodes = List.generate(
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DesignTokens.classCodeLength,
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(_) => FocusNode(),
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);
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int _failedAttempts = 0;
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DateTime? _lockoutEndTime;
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/// 当前是否被锁定
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bool get _isCurrentlyLocked {
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if (_lockoutEndTime == null) return false;
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if (DateTime.now().isAfter(_lockoutEndTime!)) {
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_lockoutEndTime = null;
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return false;
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}
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return true;
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}
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@override
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void initState() {
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super.initState();
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// 自动聚焦第一个输入框
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WidgetsBinding.instance.addPostFrameCallback((_) {
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_focusNodes[0].requestFocus();
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});
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}
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@override
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void dispose() {
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for (final c in _controllers) {
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c.dispose();
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}
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for (final f in _focusNodes) {
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f.dispose();
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}
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super.dispose();
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}
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/// 获取当前输入的班级码
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String get _classCode => _controllers.map((c) => c.text).join();
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/// 是否所有位都已输入
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bool get _isComplete =>
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_controllers.every((c) => c.text.isNotEmpty);
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/// 清空所有输入框
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void _clearInputs() {
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for (final c in _controllers) {
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c.clear();
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}
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_focusNodes[0].requestFocus();
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}
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void _onChanged(int index, String value) {
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if (value.isEmpty && index > 0) {
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// 退格清空 → 跳到前一位
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_focusNodes[index - 1].requestFocus();
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} else if (value.isNotEmpty && index < DesignTokens.classCodeLength - 1) {
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// 输入字符 → 跳到下一位
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_focusNodes[index + 1].requestFocus();
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}
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// 全部输入完成 → 自动提交
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if (_isComplete) {
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_submit();
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}
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}
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void _submit() {
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if (!_isComplete || _isCurrentlyLocked) return;
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context.read<AuthBloc>().add(ClassCodeSubmitted(_classCode));
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}
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/// 处理 AuthBloc 状态变化
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void _handleAuthState(BuildContext context, AuthState state) {
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if (state is! Authenticated) return;
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// 成功加入班级
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if (!state.needsClassCode) {
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context.go('/home');
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return;
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}
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// 班级码验证错误
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final error = state.classCodeError;
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if (error != null && error.isNotEmpty) {
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_failedAttempts++;
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// 检查是否为锁定错误
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if (error.contains('30 分钟') || error.contains('尝试次数过多')) {
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setState(() {
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_lockoutEndTime = DateTime.now().add(
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Duration(minutes: DesignTokens.classCodeLockoutMinutes),
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);
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});
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}
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// 清空输入
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_clearInputs();
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// 显示错误提示
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if (mounted) {
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ScaffoldMessenger.of(context).clearSnackBars();
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ScaffoldMessenger.of(context).showSnackBar(
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SnackBar(
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content: Text(error),
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backgroundColor: Theme.of(context).colorScheme.error,
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duration: const Duration(seconds: 3),
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),
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);
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}
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}
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}
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@override
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Widget build(BuildContext context) {
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final colorScheme = Theme.of(context).colorScheme;
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return BlocListener<AuthBloc, AuthState>(
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listener: _handleAuthState,
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child: Scaffold(
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body: SafeArea(
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child: Padding(
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padding: const EdgeInsets.symmetric(
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horizontal: DesignTokens.spacing24,
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),
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child: Column(
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children: [
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const Spacer(flex: 2),
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// 标题
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Icon(
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Icons.groups_rounded,
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size: 64,
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color: colorScheme.primary,
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),
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const SizedBox(height: DesignTokens.spacing24),
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Text(
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'加入班级',
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style: Theme.of(context).textTheme.headlineMedium?.copyWith(
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fontWeight: FontWeight.bold,
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),
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),
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const SizedBox(height: DesignTokens.spacing8),
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Text(
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'输入老师提供的 6 位班级码',
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style: Theme.of(context).textTheme.bodyLarge?.copyWith(
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color: colorScheme.onSurface.withValues(alpha: 0.6),
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),
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),
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const SizedBox(height: DesignTokens.spacing48),
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// 锁定状态 or 输入框
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if (_isCurrentlyLocked)
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_buildLockoutView(context, colorScheme)
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else
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_buildCodeInputs(context, colorScheme),
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const SizedBox(height: DesignTokens.spacing24),
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// 跳过按钮
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TextButton(
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onPressed: () => context.go('/home'),
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child: Text(
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'稍后再加入',
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style: TextStyle(
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color: colorScheme.onSurface.withValues(alpha: 0.5),
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),
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),
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),
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// 剩余尝试次数提示
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if (!_isCurrentlyLocked && _failedAttempts > 0)
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Padding(
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padding: const EdgeInsets.only(top: 8),
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child: Text(
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'剩余 ${DesignTokens.classCodeMaxAttempts - _failedAttempts} 次尝试机会',
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style: Theme.of(context).textTheme.bodySmall?.copyWith(
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color: _failedAttempts >= 4
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? colorScheme.error
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: colorScheme.onSurface.withValues(alpha: 0.5),
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),
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),
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),
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const Spacer(flex: 3),
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],
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),
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),
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),
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),
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);
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}
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/// 锁定视图 — 超过最大尝试次数后显示
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Widget _buildLockoutView(BuildContext context, ColorScheme colorScheme) {
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return Column(
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children: [
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Icon(Icons.lock_outline, size: 48, color: colorScheme.error),
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const SizedBox(height: 16),
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Text(
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'尝试次数过多',
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style: Theme.of(context).textTheme.titleMedium?.copyWith(
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fontWeight: FontWeight.bold,
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),
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),
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const SizedBox(height: 8),
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Text(
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'请等待 ${DesignTokens.classCodeLockoutMinutes} 分钟后再试',
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style: Theme.of(context).textTheme.bodyMedium?.copyWith(
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color: colorScheme.onSurface.withValues(alpha: 0.6),
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),
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),
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],
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);
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}
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/// 6 位班级码输入框
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Widget _buildCodeInputs(BuildContext context, ColorScheme colorScheme) {
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return BlocBuilder<AuthBloc, AuthState>(
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builder: (context, state) {
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final isLoading = state is Authenticated && state.isLoading;
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return Row(
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mainAxisAlignment: MainAxisAlignment.spaceEvenly,
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children: List.generate(
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DesignTokens.classCodeLength,
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(index) => _buildCodeInput(context, index, colorScheme, isLoading),
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),
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);
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},
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);
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}
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/// 单个班级码输入框
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Widget _buildCodeInput(
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BuildContext context,
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int index,
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ColorScheme colorScheme,
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bool isLoading,
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) {
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return SizedBox(
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width: 48,
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height: 56,
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child: TextField(
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controller: _controllers[index],
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focusNode: _focusNodes[index],
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enabled: !isLoading,
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textAlign: TextAlign.center,
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textAlignVertical: TextAlignVertical.center,
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style: Theme.of(context).textTheme.headlineSmall?.copyWith(
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fontWeight: FontWeight.bold,
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letterSpacing: 0,
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),
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maxLength: 1,
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keyboardType: TextInputType.text,
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textCapitalization: TextCapitalization.characters,
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decoration: InputDecoration(
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counterText: '',
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filled: true,
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fillColor: colorScheme.surfaceContainerHighest.withValues(alpha: 0.5),
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border: OutlineInputBorder(
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borderRadius: BorderRadius.circular(12),
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borderSide: BorderSide.none,
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),
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focusedBorder: OutlineInputBorder(
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borderRadius: BorderRadius.circular(12),
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borderSide: BorderSide(color: colorScheme.primary, width: 2),
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),
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),
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onChanged: (value) => _onChanged(index, value),
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onSubmitted: (_) {
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if (_isComplete) _submit();
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},
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),
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);
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}
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}
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