ar_tourism_flutter_unity/lib/unity_page.dart

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'unity_controller.dart';

class UnityPage extends StatefulWidget {
  final String? token;
  final String? sceneName;

  const UnityPage({
    Key? key, 
    this.sceneName = 'Main',
    this.token,
  }) : super(key: key);

  @override
  State<UnityPage> createState() => _UnityPageState();
}

class _UnityPageState extends State<UnityPage> with WidgetsBindingObserver {
  // Unity通信通道
  static const MethodChannel _channel = MethodChannel('com.example.ar_tourism_flutter_unity.unity');
  
  bool _isLoading = true;
  bool _hasError = false;
  String _errorMessage = '';

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _setupMessageHandler();
    _initializeUnity();
  }

  void _setupMessageHandler() {
    _channel.setMethodCallHandler((call) async {
      switch (call.method) {
        case 'onUnityBackPressed':
          print('接收到Unity返回请求');
          Navigator.of(context).pop();
          return true;
        case 'onUnityClosed':
          print('Unity已关闭');
          if (mounted) Navigator.of(context).pop();
          return true;
        default:
          return false;
      }
    });
  }

  Future<void> _initializeUnity() async {
    setState(() {
      _isLoading = true;
      _hasError = false;
    });

    try {
      // 初始化Unity
      final bool initialized = await _channel.invokeMethod('initializeUnity') ?? false;
      
      if (!initialized) {
        throw Exception('Unity初始化失败');
      }
      
      // 检查权限
      final bool hasPermissions = await _channel.invokeMethod('checkAndRequestPermissions') ?? false;
      
      if (!hasPermissions) {
        throw Exception('未获得必要权限');
      }
      
      // 启动Unity场景
      await _channel.invokeMethod('start_unity', {
        'returnToHome': true,
        'token': widget.token ?? '',
        'sceneName': widget.sceneName ?? 'Main',
      });
      
      setState(() {
        _isLoading = false;
      });
    } catch (e) {
      print('Unity启动错误: $e');
      setState(() {
        _isLoading = false;
        _hasError = true;
        _errorMessage = e.toString();
      });
    }
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.resumed) {
      // 从后台恢复时可能需要重新初始化Unity
      print('应用从后台恢复');
    } else if (state == AppLifecycleState.paused) {
      // 应用进入后台时可能需要暂停Unity
      print('应用进入后台');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        children: [
          // Unity视图或错误消息
          if (_hasError)
            Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Icon(Icons.error_outline, size: 48, color: Colors.red),
                  SizedBox(height: 16),
                  Text(
                    '加载AR内容失败',
                    style: TextStyle(color: Colors.white, fontSize: 18),
                  ),
                  SizedBox(height: 8),
                  Padding(
                    padding: const EdgeInsets.symmetric(horizontal: 24),
                    child: Text(
                      _errorMessage,
                      style: TextStyle(color: Colors.white70, fontSize: 14),
                      textAlign: TextAlign.center,
                    ),
                  ),
                  SizedBox(height: 24),
                  ElevatedButton(
                    onPressed: () {
                      Navigator.of(context).pop();
                    },
                    child: Text('返回'),
                    style: ElevatedButton.styleFrom(
                      backgroundColor: Colors.blue,
                      foregroundColor: Colors.white,
                    ),
                  ),
                ],
              ),
            )
          else if (_isLoading)
            Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  CircularProgressIndicator(
                    valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
                  ),
                  SizedBox(height: 16),
                  Text(
                    '正在加载AR内容...',
                    style: TextStyle(color: Colors.white, fontSize: 16),
                  ),
                ],
              ),
            ),
          
          // 返回按钮
          SafeArea(
            child: Padding(
              padding: const EdgeInsets.all(8.0),
              child: Align(
                alignment: Alignment.topLeft,
                child: IconButton(
                  icon: Icon(Icons.arrow_back, color: Colors.white),
                  onPressed: () => Navigator.of(context).pop(),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }

  @override
  void dispose() {
    // 清理资源
    _channel.invokeMethod('closeUnity');
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }
}