启动动画和登录页面的动画

lib/features/auth/presentation/pages/splash_page.dart

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+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:go_router/go_router.dart';
+
+import '../../../../core/router/route_paths.dart';
+import '../bloc/auth_cubit.dart';
+import '../bloc/auth_state.dart';
+
+/// 启动页：展示 App Logo 并循环播放「呼吸缩放」动画。
+///
+/// 该页面作为 App 的第一个路由，衔接原生启动屏（静态 Logo）。
+/// 动画会一直循环，直到 [AuthCubit.appStarted] 完成、登录态确定
+/// （[AuthAuthenticated] / [AuthUnauthenticated]）这一「就绪信号」到来，
+/// 才停止动画并跳转到首页或登录页。
+class SplashPage extends StatefulWidget {
+  const SplashPage({super.key});
+
+  @override
+  State<SplashPage> createState() => _SplashPageState();
+}
+
+class _SplashPageState extends State<SplashPage>
+    with SingleTickerProviderStateMixin {
+  /// 呼吸动画控制器（循环往复）
+  late final AnimationController _breathController;
+
+  /// 就绪信号是否已到达
+  bool _ready = false;
+
+  /// 就绪后的目标登录态
+  AuthState? _resolvedState;
+
+  /// 防止重复跳转
+  bool _navigated = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _breathController = AnimationController(
+      vsync: this,
+      duration: const Duration(milliseconds: 900),
+    )..repeat(reverse: true);
+
+    // 处理进入 splash 时登录态已经确定的情况（appStarted 先于首帧完成）
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (mounted) _onReady(context.read<AuthCubit>().state);
+    });
+  }
+
+  @override
+  void dispose() {
+    _breathController.dispose();
+    super.dispose();
+  }
+
+  /// 记录就绪信号，并尝试跳转
+  void _onReady(AuthState state) {
+    if (state is AuthAuthenticated || state is AuthUnauthenticated) {
+      _resolvedState = state;
+      _ready = true;
+      _maybeNavigate();
+    }
+    // AuthInitial：尚未就绪，继续停留在启动页播放动画
+  }
+
+  /// 就绪信号到达即离开启动页，不额外增加打开时间
+  void _maybeNavigate() {
+    if (_navigated || !mounted) return;
+    if (!_ready || _resolvedState == null) return;
+
+    _navigated = true;
+    _breathController.stop();
+    if (_resolvedState is AuthAuthenticated) {
+      context.go(RoutePaths.home);
+    } else {
+      context.go(RoutePaths.login);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return BlocListener<AuthCubit, AuthState>(
+      listenWhen: (prev, cur) =>
+          cur is AuthAuthenticated || cur is AuthUnauthenticated,
+      listener: (context, state) => _onReady(state),
+      child: Scaffold(
+        // 与原生启动屏白底保持一致，避免切换时闪色
+        backgroundColor: Colors.white,
+        body: Center(
+          child: AnimatedBuilder(
+            animation: _breathController,
+            builder: (context, child) {
+              // easeInOut 让呼吸更柔和；scale 从 1.0 起始以贴合原生屏尺寸
+              final t = Curves.easeInOut.transform(_breathController.value);
+              final scale = 1.0 - 0.22 * t; // 1.0 -> 0.78，幅度更大更明显
+              final opacity = 1.0 - 0.55 * t; // 1.0 -> 0.45
+              return Opacity(
+                opacity: opacity,
+                child: Transform.scale(scale: scale, child: child),
+              );
+            },
+            // 透明底应用图标，避免白底上出现浅灰"阴影"底块
+            child: Image.asset(
+              'assets/images/app_logo_gray_transparent.png',
+              width: 180,
+              height: 180,
+              fit: BoxFit.contain,
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}