暂时把bug先处理掉了，准备尝试实现最小播放目标

lib/services/playback_service.dart

@@ -1,5 +1,4 @@
 import 'package:media_kit/media_kit.dart';
-import 'package:media_kit/media_kit.dart' as media_kit;
 
 class PlaybackService {
   static final PlaybackService _instance = PlaybackService._();
@@ -7,22 +6,61 @@ class PlaybackService {
   PlaybackService._();
 
   late final Player _player;
-  bool get isInitialized => _player.state.playing;
+  bool _initialized = false;
 
   void init() {
+    if (_initialized) return;
     _player = Player();
+    _initialized = true;
   }
 
   Future<void> play(String url) async {
+    if (!_initialized) init();
     await _player.open(Media(url));
     await _player.play();
   }
 
-  void pause() => _player.pause();
-  void resume() => _player.play();
-  void stop() => _player.stop();
-  void dispose() => _player.dispose();
+  void pause() {
+    if (_initialized) {
+      _player.pause();
+    }
+  }
 
-  // 状态流
-  Stream<PlayerState> get stateStream => _player.stream;
+  void resume() {
+    if (_initialized) {
+      _player.play();
+    }
+  }
+
+  void stop() {
+    if (_initialized) {
+      _player.stop();
+    }
+  }
+
+  void dispose() {
+    if (_initialized) {
+      _player.dispose();
+      _initialized = false;
+    }
+  }
+
+  // ✅ 直接返回 PlayerStream（它就是播放器的状态流）
+  PlayerStream get stateStream {
+    if (!_initialized) init();
+    return _player.stream;
+  }
+
+  // 获取当前播放状态
+  PlayerState get currentState {
+    if (!_initialized) {
+      return PlayerState(
+        playing: false,
+        position: Duration.zero,
+        duration: Duration.zero,
+        buffering: false,
+      );
+    }
+    return _player.state;
+  }
 }