feat(app): 完善播放协议搜索与空状态

lib/pages/player/widgets/home_feed_overlay.dart

@@ -110,12 +110,16 @@ class HomeFeedOverlay extends StatefulWidget {
 }
 
 class _HomeFeedOverlayState extends State<HomeFeedOverlay> {
-  static const Duration _singleTapDelay = Duration(milliseconds: 320);
+  static const Duration _singleTapDelay = Duration(milliseconds: 400);
 
   bool _scrubbing = false;
   bool _wasVisibleBeforeScrub = true;
   Timer? _singleTapTimer;
-  DateTime? _lastTapAt;
+  DateTime? _lastDownAt;
+  DateTime? _blockSingleTapUntil;
+  bool _doubleTapDown = false;
+  bool _likedThisPair = false;
+  int _downSerial = 0;
   int _tapSeq = 0;
   int _nextHeartBurstId = 0;
   final List<({int id, Offset position})> _heartBursts = [];
@@ -146,6 +150,7 @@ class _HomeFeedOverlayState extends State<HomeFeedOverlay> {
               builder: (context, constraints) => Listener(
                 onPointerUp: (_) => widget.onBoostEnd(),
                 onPointerCancel: (_) => widget.onBoostEnd(),
+                onPointerDown: _handlePointerDown,
                 child: GestureDetector(
                   key: const Key('home-feed-gesture'),
                   behavior: HitTestBehavior.opaque,
@@ -258,38 +263,66 @@ class _HomeFeedOverlayState extends State<HomeFeedOverlay> {
     widget.onScrubEnd?.call(wasVisible);
   }
 
-  void _handleTapUp(TapUpDetails details) {
-    final tapSeq = ++_tapSeq;
-    final now = widget.now?.call() ?? DateTime.now();
-    final lastTap = _lastTapAt;
-    if (lastTap != null && now.difference(lastTap) <= _singleTapDelay) {
-      _tapSeq++;
-      _singleTapTimer?.cancel();
-      _singleTapTimer = null;
-      _lastTapAt = null;
-      _showHearts(details.localPosition);
+  DateTime _now() => widget.now?.call() ?? DateTime.now();
+
+  void _handlePointerDown(PointerDownEvent event) {
+    final now = _now();
+    final previous = _lastDownAt;
+    _downSerial++;
+    _lastDownAt = now;
+    final repeated =
+        previous != null && now.difference(previous) <= _singleTapDelay;
+    if (!repeated) {
+      if (_singleTapBlocked(now)) return;
+      _doubleTapDown = false;
+      _likedThisPair = false;
       return;
     }
-    _lastTapAt = now;
+    _doubleTapDown = true;
+    _blockSingleTapUntil = now.add(_singleTapDelay);
+    _cancelPendingSingleTap();
+  }
+
+  bool _singleTapBlocked(DateTime now) {
+    final blockedUntil = _blockSingleTapUntil;
+    return blockedUntil != null && now.isBefore(blockedUntil);
+  }
+
+  void _cancelPendingSingleTap() {
+    _tapSeq++;
+    _singleTapTimer?.cancel();
+    _singleTapTimer = null;
+  }
+
+  void _handleTapUp(TapUpDetails details) {
+    final now = _now();
+    if (_doubleTapDown || _singleTapBlocked(now)) {
+      _showDoubleTapLike(details.localPosition);
+      return;
+    }
+    final serial = _downSerial;
+    final tapSeq = ++_tapSeq;
     _singleTapTimer?.cancel();
     late final Timer pending;
     pending = Timer(_singleTapDelay, () {
-      if (identical(_singleTapTimer, pending)) {
-        _singleTapTimer = null;
-      }
-      if (tapSeq != _tapSeq) return;
-      final latestTap = _lastTapAt;
-      if (latestTap != null &&
-          (widget.now?.call() ?? DateTime.now()).difference(latestTap) <
-              _singleTapDelay) {
-        return;
-      }
-      _lastTapAt = null;
-      if (mounted) widget.onTogglePlay();
+      if (!identical(_singleTapTimer, pending)) return;
+      _singleTapTimer = null;
+      if (!mounted || tapSeq != _tapSeq || serial != _downSerial) return;
+      if (_doubleTapDown || _singleTapBlocked(_now())) return;
+      _lastDownAt = null;
+      widget.onTogglePlay();
     });
     _singleTapTimer = pending;
   }
 
+  void _showDoubleTapLike(Offset position) {
+    if (_likedThisPair) return;
+    _likedThisPair = true;
+    _blockSingleTapUntil = _now().add(_singleTapDelay);
+    _cancelPendingSingleTap();
+    _showHearts(position);
+  }
+
   void _showHearts(Offset position) {
     final id = _nextHeartBurstId++;
     setState(() => _heartBursts.add((id: id, position: position)));
@@ -302,11 +335,11 @@ class _HomeFeedOverlayState extends State<HomeFeedOverlay> {
   }
 
   void _handleLongPressStart(LongPressStartDetails details, double width) {
-    _tapSeq++;
-    _singleTapTimer?.cancel();
-    _singleTapTimer = null;
-    _lastTapAt = null;
     final third = width / 3;
+    _tapSeq++;
+    _cancelPendingSingleTap();
+    _doubleTapDown = false;
+    _lastDownAt = null;
     final dx = details.localPosition.dx;
     if (dx < third || dx > width - third) {
       widget.onBoostStart();