feat(app): 完善播放协议搜索与空状态

lib/pages/player/widgets/player_double_tap_hearts.dart

@@ -1,11 +1,39 @@
 // Author: fruit.com.cn
 
-import 'dart:math';
-
 import 'package:flutter/material.dart';
 
 import '../../../core/theme/app_colors.dart';
 
+const int _heartDurationMs = 680;
+const double _heartPopPortion = 0.18;
+const double _heartStartScale = 0.7;
+const double _heartHoldPortion = 0.45;
+
+const List<_HeartParticle> _hearts = [
+  _HeartParticle(
+    delay: 0,
+    travel: 108,
+    drift: 0,
+    size: 48,
+    color: AppColors.doubleTapHeartRed,
+  ),
+  _HeartParticle(
+    delay: 50,
+    travel: 96,
+    drift: -28,
+    size: 36,
+    color: AppColors.doubleTapHeartPink,
+  ),
+  _HeartParticle(
+    delay: 90,
+    travel: 118,
+    drift: 26,
+    size: 40,
+    color: AppColors.doubleTapHeartRed,
+  ),
+];
+
+/// 双击点赞时，在点击位置飘出一小簇心。
 class PlayerDoubleTapHeartBurst extends StatefulWidget {
   const PlayerDoubleTapHeartBurst({super.key, required this.onCompleted});
 
@@ -19,30 +47,14 @@ class PlayerDoubleTapHeartBurst extends StatefulWidget {
 class _PlayerDoubleTapHeartBurstState extends State<PlayerDoubleTapHeartBurst>
     with SingleTickerProviderStateMixin {
   late final AnimationController _controller;
-  late final List<_HeartParticle> _particles;
   bool _completed = false;
 
   @override
   void initState() {
     super.initState();
-    final random = Random();
-    var delay = 0;
-    _particles = List.generate(3 + random.nextInt(2), (index) {
-      if (index > 0) delay += 40 + random.nextInt(21);
-      return _HeartParticle(
-        delay: delay,
-        duration: 600 + random.nextInt(101),
-        travel: 90 + random.nextInt(31),
-        drift: -18 + random.nextInt(37),
-        size: (20 + random.nextInt(7)).toDouble(),
-        color: random.nextBool()
-            ? AppColors.doubleTapHeartRed
-            : AppColors.doubleTapHeartPink,
-      );
-    });
-    final total = _particles
-        .map((particle) => particle.delay + particle.duration)
-        .reduce(max);
+    final total = _hearts
+        .map((heart) => heart.delay + _heartDurationMs)
+        .reduce((left, right) => left > right ? left : right);
     _controller = AnimationController(
       vsync: this,
       duration: Duration(milliseconds: total),
@@ -76,7 +88,8 @@ class _PlayerDoubleTapHeartBurstState extends State<PlayerDoubleTapHeartBurst>
             return Stack(
               clipBehavior: Clip.none,
               children: [
-                for (final particle in _particles) _particle(particle, elapsed),
+                for (var index = 0; index < _hearts.length; index++)
+                  _heart(_hearts[index], elapsed, index),
               ],
             );
           },
@@ -85,27 +98,32 @@ class _PlayerDoubleTapHeartBurstState extends State<PlayerDoubleTapHeartBurst>
     );
   }
 
-  Widget _particle(_HeartParticle particle, double elapsed) {
-    final progress = ((elapsed - particle.delay) / particle.duration).clamp(
+  Widget _heart(_HeartParticle heart, double elapsed, int index) {
+    final progress = ((elapsed - heart.delay) / _heartDurationMs).clamp(
       0.0,
       1.0,
     );
     if (progress <= 0) return const SizedBox.shrink();
     final move = Curves.easeOutCubic.transform(progress);
-    final scale = progress < 0.3
-        ? 0.55 + (1.15 - 0.55) * (progress / 0.3)
-        : 1.15 - (1.15 - 0.2) * ((progress - 0.3) / 0.7);
+    final scale = progress < _heartPopPortion
+        ? _heartStartScale +
+              (1 - _heartStartScale) * (progress / _heartPopPortion)
+        : 1.0;
+    final opacity = progress < _heartHoldPortion
+        ? 1.0
+        : 1 - ((progress - _heartHoldPortion) / (1 - _heartHoldPortion));
     return Positioned(
-      left: particle.drift * move - particle.size / 2,
-      top: -particle.travel * move,
+      left: heart.drift * move - heart.size / 2,
+      top: -heart.size / 2 - heart.travel * move,
       child: Opacity(
-        opacity: 1 - Curves.easeIn.transform(progress),
+        opacity: opacity.clamp(0.0, 1.0),
         child: Transform.scale(
           scale: scale,
           child: Icon(
+            key: Key('double-tap-heart-$index'),
             Icons.favorite_rounded,
-            color: particle.color,
-            size: particle.size,
+            color: heart.color,
+            size: heart.size,
           ),
         ),
       ),
@@ -116,7 +134,6 @@ class _PlayerDoubleTapHeartBurstState extends State<PlayerDoubleTapHeartBurst>
 class _HeartParticle {
   const _HeartParticle({
     required this.delay,
-    required this.duration,
     required this.travel,
     required this.drift,
     required this.size,
@@ -124,9 +141,8 @@ class _HeartParticle {
   });
 
   final int delay;
-  final int duration;
-  final int travel;
-  final int drift;
+  final double travel;
+  final double drift;
   final double size;
   final Color color;
 }