后台播放能力已调通，介入部分细节优化

2026-08-20 22:36:10 +08:00
parent f94cda4234
commit bb8e4caf48
2 changed files with 303 additions and 49 deletions
@@ -0,0 +1,189 @@
+// lib/services/app_lifecycle_manager.dart
+import 'dart:async';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:media_kit/media_kit.dart';
+
+/// App 生命周期状态（扩展了 Flutter 原生状态）
+enum AppLifecycleStatus {
+  /// 应用正在启动（初始化阶段）
+  launching,
+
+  /// 应用在前台，用户可交互
+  resumed,
+
+  /// 应用在前台但不可交互（如：来电、系统弹窗）
+  inactive,
+
+  /// 应用在后台
+  paused,
+
+  /// 应用即将被销毁
+  detached,
+
+  /// 应用已进入后台且播放停止（自定义，用于播放策略）
+  backgroundIdle,
+}
+
+/// App 生命周期管理器
+///
+/// 职责：
+/// 1. 统一监听 Flutter 的 AppLifecycleState
+/// 2. 管理播放器在前后台的行为
+/// 3. 管理渲染调度器的运行状态
+/// 4. 管理 WebDAV 的缓存策略
+class AppLifecycleManager extends ChangeNotifier {
+  static final AppLifecycleManager _instance = AppLifecycleManager._internal();
+  factory AppLifecycleManager() => _instance;
+  AppLifecycleManager._internal();
+
+  // ---- 当前状态 ----
+  AppLifecycleStatus _status = AppLifecycleStatus.launching;
+  AppLifecycleStatus get status => _status;
+
+  // ---- 上次进入后台的时间 ----
+  DateTime? _backgroundedAt;
+  DateTime? get backgroundedAt => _backgroundedAt;
+
+  // ---- 是否在后台 ----
+  bool get isInBackground =>
+      _status == AppLifecycleStatus.paused ||
+      _status == AppLifecycleStatus.inactive ||
+      _status == AppLifecycleStatus.detached;
+
+  bool get isInForeground => _status == AppLifecycleStatus.resumed;
+
+  // ---- 后台时长 ----
+  Duration get backgroundDuration {
+    if (_backgroundedAt == null) return Duration.zero;
+    return DateTime.now().difference(_backgroundedAt!);
+  }
+
+  // ---- 是否处于"长后台"（超过 5 分钟） ----
+  bool get isLongBackground => backgroundDuration > const Duration(minutes: 5);
+
+  // ---- 监听器 ----
+  final List<void Function(AppLifecycleStatus)> _listeners = [];
+
+  // ---- Flutter 原生生命周期订阅 ----
+  late final WidgetsBindingObserver _observer;
+  bool _isObserving = false;
+
+  // ---- 初始化 ----
+  void init() {
+    if (_isObserving) return;
+    _isObserving = true;
+
+    _observer = _AppLifecycleObserver(this);
+    WidgetsBinding.instance.addObserver(_observer);
+
+    // 获取初始状态
+    _updateStatus(AppLifecycleStatus.resumed);
+
+    debugPrint('📱 AppLifecycleManager 已初始化');
+  }
+
+  // ---- 状态更新 ----
+  void _handleNativeState(AppLifecycleState state) {
+    final newStatus = _convertNativeState(state);
+
+    // 状态变化时更新
+    if (newStatus != _status) {
+      _updateStatus(newStatus);
+    }
+
+    // 记录进入后台的时间
+    if (newStatus == AppLifecycleStatus.paused ||
+        newStatus == AppLifecycleStatus.inactive) {
+      if (_backgroundedAt == null) {
+        _backgroundedAt = DateTime.now();
+        debugPrint('📱 App 进入后台: ${_backgroundedAt}');
+      }
+    }
+
+    // 回到前台时，如果是长后台，触发通知
+    if (newStatus == AppLifecycleStatus.resumed) {
+      if (_backgroundedAt != null) {
+        final duration = backgroundDuration;
+        debugPrint('📱 App 回到前台，后台时长: ${duration.inMinutes}分钟');
+        _backgroundedAt = null;
+
+        // 如果是长后台，通知监听器做重连等操作
+        if (duration > const Duration(minutes: 5)) {
+          _notifyListeners(AppLifecycleStatus.backgroundIdle);
+        }
+      }
+    }
+  }
+
+  void _updateStatus(AppLifecycleStatus newStatus) {
+    final oldStatus = _status;
+    _status = newStatus;
+    debugPrint('📱 生命周期状态变化: $oldStatus → $newStatus');
+    notifyListeners();
+    _notifyListeners(newStatus);
+  }
+
+  AppLifecycleStatus _convertNativeState(AppLifecycleState state) {
+    switch (state) {
+      case AppLifecycleState.resumed:
+        return AppLifecycleStatus.resumed;
+      case AppLifecycleState.inactive:
+        return AppLifecycleStatus.inactive;
+      case AppLifecycleState.paused:
+        return AppLifecycleStatus.paused;
+      case AppLifecycleState.detached:
+        return AppLifecycleStatus.detached;
+      default:
+        return AppLifecycleStatus.paused;
+    }
+  }
+
+  // ---- 自定义监听器管理 ----
+  void addListenerToManager(void Function(AppLifecycleStatus) listener) {
+    _listeners.add(listener);
+  }
+
+  void removeListenerFromManager(void Function(AppLifecycleStatus) listener) {
+    _listeners.remove(listener);
+  }
+
+  void _notifyListeners(AppLifecycleStatus status) {
+    for (final listener in _listeners) {
+      try {
+        listener(status);
+      } catch (e) {
+        debugPrint('❌ 生命周期监听器执行失败: $e');
+      }
+    }
+  }
+
+  // ---- 检查是否需要重新连接 WebDAV ----
+  bool get shouldRecheckWebDAV {
+    if (!isInForeground) return false;
+    if (_backgroundedAt == null) return false;
+    return isLongBackground;
+  }
+
+  // ---- 释放 ----
+  void dispose() {
+    if (_isObserving) {
+      WidgetsBinding.instance.removeObserver(_observer);
+      _isObserving = false;
+    }
+    _listeners.clear();
+    super.dispose();
+  }
+}
+
+/// 内部观察者（绑定 WidgetsBinding）
+class _AppLifecycleObserver extends WidgetsBindingObserver {
+  final AppLifecycleManager _manager;
+
+  _AppLifecycleObserver(this._manager);
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    _manager._handleNativeState(state);
+  }
+}