播放页部分调整，播放链路已打通

lib/pages/player_page.dart

@@ -11,6 +11,8 @@ class PlayerPage extends StatefulWidget {
 }
 
 class _PlayerPageState extends State<PlayerPage> {
+  double? _dragProgress; // 拖动时的临时进度
+
   String _formatDuration(Duration d) {
     if (d.inMilliseconds < 0) return '00:00';
     final minutes = d.inMinutes;
@@ -38,10 +40,20 @@ class _PlayerPageState extends State<PlayerPage> {
     final isPlaying = service.isPlaying;
     final position = service.position;
     final duration = service.duration;
+    final bufferedPosition = service.bufferedPosition;
+
     final progress = duration.inMilliseconds > 0
         ? position.inMilliseconds / duration.inMilliseconds
         : 0.0;
 
+    final bufferProgress = duration.inMilliseconds > 0
+        ? (bufferedPosition.inMilliseconds / duration.inMilliseconds)
+            .clamp(0.0, 1.0)
+        : 0.0;
+
+    // 拖动时显示拖动的进度，否则显示实际播放进度
+    final displayProgress = _dragProgress ?? progress;
+
     return Scaffold(
       backgroundColor: const Color(0xFF0E1211),
       appBar: AppBar(
@@ -125,22 +137,95 @@ class _PlayerPageState extends State<PlayerPage> {
             ),
             const SizedBox(height: 40),
 
-            // ---- 进度条 ----
+// ---- 双层进度条（视觉与交互分离） ----
             Column(
               children: [
-                Slider(
-                  value: progress.clamp(0.0, 1.0),
-                  onChanged: (value) {
-                    final newPosition = Duration(
-                      milliseconds: (value * duration.inMilliseconds).round(),
-                    );
-                    service.seekTo(newPosition);
-                  },
-                  activeColor: const Color(0xFFB8D4D0),
-                  inactiveColor: Colors.grey[800],
-                  min: 0.0,
-                  max: 1.0,
+                SizedBox(
+                  height: 20,
+                  child: LayoutBuilder(
+                    builder: (context, constraints) {
+                      final width = constraints.maxWidth;
+
+                      final bufferWidth =
+                          width * bufferProgress.clamp(0.0, 1.0);
+                      final progressWidth = width * progress.clamp(0.0, 1.0);
+
+                      return Stack(
+                        alignment: Alignment.centerLeft,
+                        children: [
+                          // ① 底层：整首歌曲（暗灰色）
+                          Container(
+                            width: width,
+                            height: 4,
+                            decoration: BoxDecoration(
+                              color: Colors.grey[800],
+                              borderRadius: BorderRadius.circular(2),
+                            ),
+                          ),
+
+                          // ② 缓冲层（深青色）
+                          Container(
+                            width: bufferWidth,
+                            height: 4,
+                            decoration: BoxDecoration(
+                              color: const Color(0xFF4A7A7A),
+                              borderRadius: BorderRadius.circular(2),
+                            ),
+                          ),
+
+                          // ③ 播放进度层（亮青色）
+                          Container(
+                            width: progressWidth,
+                            height: 4,
+                            decoration: BoxDecoration(
+                              color: const Color(0xFFB8D4D0),
+                              borderRadius: BorderRadius.circular(2),
+                            ),
+                          ),
+
+                          // ④ 交互层（只负责手势，不显示任何轨道）
+                          Positioned.fill(
+                            child: SliderTheme(
+                              data: SliderTheme.of(context).copyWith(
+                                trackHeight: 0,
+                                activeTrackColor: Colors.transparent,
+                                inactiveTrackColor: Colors.transparent,
+                                thumbColor: Colors.transparent, // ✅ 完全隐藏小球
+                                overlayColor: Colors.transparent,
+                                thumbShape: const RoundSliderThumbShape(
+                                  enabledThumbRadius: 0,
+                                ),
+                              ),
+                              child: Slider(
+                                value: progress.clamp(0.0, 1.0),
+                                min: 0.0,
+                                max: 1.0,
+                                onChanged: (value) {
+                                  // 拖动时只更新本地状态，不触发 seek
+                                  setState(() {
+                                    _dragProgress = value;
+                                  });
+                                },
+                                onChangeEnd: (value) {
+                                  final newPosition = Duration(
+                                    milliseconds:
+                                        (value * duration.inMilliseconds)
+                                            .round(),
+                                  );
+                                  service.seekTo(newPosition);
+                                  setState(() {
+                                    _dragProgress = null;
+                                  });
+                                },
+                              ),
+                            ),
+                          ),
+                        ],
+                      );
+                    },
+                  ),
                 ),
+                // 时间显示
                 Row(
                   mainAxisAlignment: MainAxisAlignment.spaceBetween,
                   children: [