feat(splash): 将 fallback 动画改为帧动画以提升兼容性

- 将 Tween 动画替换为 53 帧 PNG 序列动画
- 添加 splash_frames 资源目录（15fps，约3.5秒）
- 使用 gaplessPlayback 防止帧切换闪烁
- 保留帧加载失败时的静态 fallback

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mobile-app/lib/features/auth/presentation/pages/splash_page.dart

@@ -16,8 +16,7 @@ class SplashPage extends ConsumerStatefulWidget {
   ConsumerState<SplashPage> createState() => _SplashPageState();
 }
 
-class _SplashPageState extends ConsumerState<SplashPage>
-    with SingleTickerProviderStateMixin {
+class _SplashPageState extends ConsumerState<SplashPage> {
   /// 视频播放控制器
   VideoPlayerController? _videoController;
 
@@ -33,17 +32,17 @@ class _SplashPageState extends ConsumerState<SplashPage>
   /// 视频加载是否失败（使用 fallback 动画）
   bool _videoFailed = false;
 
-  /// Fallback 动画控制器
-  AnimationController? _fallbackAnimationController;
+  /// 帧动画总帧数
+  static const int _totalFrames = 53;
 
-  /// Logo 缩放动画
-  Animation<double>? _logoScaleAnimation;
+  /// 帧动画帧率 (fps)
+  static const int _frameRate = 15;
 
-  /// Logo 透明度动画
-  Animation<double>? _logoOpacityAnimation;
+  /// 当前显示的帧索引
+  int _currentFrameIndex = 0;
 
-  /// 文字透明度动画
-  Animation<double>? _textOpacityAnimation;
+  /// 帧动画是否正在播放
+  bool _isFrameAnimationPlaying = false;
 
   @override
   void initState() {
@@ -55,7 +54,6 @@ class _SplashPageState extends ConsumerState<SplashPage>
   void dispose() {
     _videoController?.removeListener(_onVideoStateChanged);
     _videoController?.dispose();
-    _fallbackAnimationController?.dispose();
     super.dispose();
   }
 
@@ -130,77 +128,18 @@ class _SplashPageState extends ConsumerState<SplashPage>
     }
   }
 
-  /// 启动 fallback 动画（视频加载失败时使用）
+  /// 启动 fallback 帧动画（视频加载失败时使用）
   void _startFallbackAnimation() {
-    debugPrint('[SplashPage] 启动 fallback 动画');
+    debugPrint('[SplashPage] 启动 fallback 帧动画，共 $_totalFrames 帧');
 
     setState(() {
       _videoFailed = true;
+      _isFrameAnimationPlaying = true;
+      _currentFrameIndex = 0;
     });
 
-    // 创建动画控制器，总时长 3 秒
-    _fallbackAnimationController = AnimationController(
-      vsync: this,
-      duration: const Duration(milliseconds: 3000),
-    );
-
-    // Logo 缩放动画：0.5 -> 1.0 -> 1.05 -> 1.0（弹性效果）
-    _logoScaleAnimation = TweenSequence<double>([
-      TweenSequenceItem(
-        tween: Tween<double>(begin: 0.5, end: 1.05)
-            .chain(CurveTween(curve: Curves.easeOutBack)),
-        weight: 40,
-      ),
-      TweenSequenceItem(
-        tween: Tween<double>(begin: 1.05, end: 1.0)
-            .chain(CurveTween(curve: Curves.easeInOut)),
-        weight: 10,
-      ),
-      TweenSequenceItem(
-        tween: ConstantTween<double>(1.0),
-        weight: 50,
-      ),
-    ]).animate(_fallbackAnimationController!);
-
-    // Logo 透明度动画：0 -> 1
-    _logoOpacityAnimation = TweenSequence<double>([
-      TweenSequenceItem(
-        tween: Tween<double>(begin: 0.0, end: 1.0)
-            .chain(CurveTween(curve: Curves.easeOut)),
-        weight: 30,
-      ),
-      TweenSequenceItem(
-        tween: ConstantTween<double>(1.0),
-        weight: 70,
-      ),
-    ]).animate(_fallbackAnimationController!);
-
-    // 文字透明度动画：延迟出现
-    _textOpacityAnimation = TweenSequence<double>([
-      TweenSequenceItem(
-        tween: ConstantTween<double>(0.0),
-        weight: 30,
-      ),
-      TweenSequenceItem(
-        tween: Tween<double>(begin: 0.0, end: 1.0)
-            .chain(CurveTween(curve: Curves.easeOut)),
-        weight: 20,
-      ),
-      TweenSequenceItem(
-        tween: ConstantTween<double>(1.0),
-        weight: 50,
-      ),
-    ]).animate(_fallbackAnimationController!);
-
-    // 动画完成后跳转
-    _fallbackAnimationController!.addStatusListener((status) {
-      if (status == AnimationStatus.completed) {
-        _navigateToNextPage();
-      }
-    });
-
-    // 开始动画
-    _fallbackAnimationController!.forward();
+    // 启动帧动画播放
+    _playFrameAnimation();
 
     // 1秒后显示跳过按钮
     Future.delayed(const Duration(seconds: 1), () {
@@ -212,9 +151,29 @@ class _SplashPageState extends ConsumerState<SplashPage>
     });
   }
 
-  /// 跳过 fallback 动画
+  /// 播放帧动画
+  Future<void> _playFrameAnimation() async {
+    final frameDuration = Duration(milliseconds: 1000 ~/ _frameRate);
+
+    while (_isFrameAnimationPlaying && _currentFrameIndex < _totalFrames && mounted) {
+      await Future.delayed(frameDuration);
+
+      if (!mounted || !_isFrameAnimationPlaying) break;
+
+      setState(() {
+        _currentFrameIndex++;
+      });
+    }
+
+    // 动画播放完成
+    if (_currentFrameIndex >= _totalFrames && mounted && _isFrameAnimationPlaying) {
+      _navigateToNextPage();
+    }
+  }
+
+  /// 跳过 fallback 帧动画
   void _skipFallbackAnimation() {
-    _fallbackAnimationController?.stop();
+    _isFrameAnimationPlaying = false;
     _navigateToNextPage();
   }
 
@@ -372,44 +331,43 @@ class _SplashPageState extends ConsumerState<SplashPage>
     );
   }
 
-  /// 构建 fallback 动画视图（视频加载失败时使用）
+  /// 构建 fallback 帧动画视图（视频加载失败时使用）
   Widget _buildFallbackAnimationView() {
-    return AnimatedBuilder(
-      animation: _fallbackAnimationController!,
-      builder: (context, child) {
-        return Container(
-          width: double.infinity,
-          height: double.infinity,
-          decoration: const BoxDecoration(
-            gradient: LinearGradient(
-              begin: Alignment.topCenter,
-              end: Alignment.bottomCenter,
-              colors: [
-                Color(0xFFFFF5E6),
-                Color(0xFFFFE4B5),
-              ],
-            ),
-          ),
-          child: Column(
-            mainAxisAlignment: MainAxisAlignment.center,
-            children: [
-              // Logo 带缩放和透明度动画
-              Opacity(
-                opacity: _logoOpacityAnimation?.value ?? 1.0,
-                child: Transform.scale(
-                  scale: _logoScaleAnimation?.value ?? 1.0,
-                  child: Image.asset(
-                    'assets/images/logo/app_icon.png',
-                    width: 128,
-                    height: 128,
-                  ),
-                ),
+    // 帧文件名格式: frame_001.png, frame_002.png, ... frame_053.png
+    final frameNumber = (_currentFrameIndex + 1).toString().padLeft(3, '0');
+    final framePath = 'assets/images/splash_frames/frame_$frameNumber.png';
+
+    return SizedBox.expand(
+      child: Image.asset(
+        framePath,
+        fit: BoxFit.cover,
+        gaplessPlayback: true, // 关键：防止帧切换时闪烁
+        errorBuilder: (context, error, stackTrace) {
+          // 帧加载失败时显示静态 fallback
+          debugPrint('[SplashPage] 帧加载失败: $framePath, 错误: $error');
+          return Container(
+            width: double.infinity,
+            height: double.infinity,
+            decoration: const BoxDecoration(
+              gradient: LinearGradient(
+                begin: Alignment.topCenter,
+                end: Alignment.bottomCenter,
+                colors: [
+                  Color(0xFFFFF5E6),
+                  Color(0xFFFFE4B5),
+                ],
               ),
-              const SizedBox(height: 24),
-              // 文字带透明度动画
-              Opacity(
-                opacity: _textOpacityAnimation?.value ?? 1.0,
-                child: const Text(
+            ),
+            child: Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: [
+                Image.asset(
+                  'assets/images/logo/app_icon.png',
+                  width: 128,
+                  height: 128,
+                ),
+                const SizedBox(height: 24),
+                const Text(
                   '榴莲皇后',
                   style: TextStyle(
                     fontSize: 32,
@@ -420,25 +378,11 @@ class _SplashPageState extends ConsumerState<SplashPage>
                     color: Color(0xFF4A3F35),
                   ),
                 ),
-              ),
-              const SizedBox(height: 16),
-              // 副标题（延迟显示）
-              Opacity(
-                opacity: _textOpacityAnimation?.value ?? 1.0,
-                child: const Text(
-                  '认种榴莲 · 共享收益',
-                  style: TextStyle(
-                    fontSize: 16,
-                    fontFamily: 'Noto Sans SC',
-                    fontWeight: FontWeight.w400,
-                    color: Color(0xFF8B7355),
-                  ),
-                ),
-              ),
-            ],
-          ),
-        );
-      },
+              ],
+            ),
+          );
+        },
+      ),
     );
   }
 

frontend/mobile-app/pubspec.yaml

@@ -107,6 +107,7 @@ flutter:
     - assets/images/backgrounds/
     - assets/images/avatars/
     - assets/images/illustrations/
+    - assets/images/splash_frames/
     - assets/icons/
     - assets/icons/nav/
     - assets/icons/tokens/