fix(player): 预解码观看全集首帧

lib/pages/player/player_frame_capture.dart

@@ -6,11 +6,56 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 
+import '../../core/config/app_config.dart';
+
+class PreparedPlayerFrame {
+  const PreparedPlayerFrame({this.bytes, this.provider});
+
+  final Uint8List? bytes;
+  final ImageProvider<Object>? provider;
+
+  bool get isReady => bytes != null || provider != null;
+}
+
 class PlayerFrameCapture {
   const PlayerFrameCapture._();
 
   static const int budgetMilliseconds = 32;
 
+  static Future<PreparedPlayerFrame> captureAndPrecache({
+    required BuildContext context,
+    required GlobalKey boundaryKey,
+    required String source,
+    String? fallbackPosterUrl,
+  }) async {
+    final bytes = await capture(
+      context: context,
+      boundaryKey: boundaryKey,
+      source: source,
+    );
+    if (bytes != null) {
+      if (!context.mounted) return const PreparedPlayerFrame();
+      final provider = MemoryImage(bytes);
+      if (await _precache(context, provider, source: source, kind: 'capture')) {
+        _log(
+          '[player-entry] phase=frame-precached source=$source kind=capture',
+        );
+        return PreparedPlayerFrame(bytes: bytes, provider: provider);
+      }
+    }
+
+    final poster = fallbackPosterUrl?.trim() ?? '';
+    if (poster.isNotEmpty) {
+      if (!context.mounted) return const PreparedPlayerFrame();
+      final provider = NetworkImage(AppConfig.mediaUrl(poster));
+      if (await _precache(context, provider, source: source, kind: 'poster')) {
+        _log('[player-entry] phase=frame-precached source=$source kind=poster');
+        return PreparedPlayerFrame(provider: provider);
+      }
+    }
+    return const PreparedPlayerFrame();
+  }
+
   static Future<Uint8List?> capture({
     required BuildContext context,
     required GlobalKey boundaryKey,
@@ -57,6 +102,32 @@ class PlayerFrameCapture {
     }
   }
 
+  static Future<bool> _precache(
+    BuildContext context,
+    ImageProvider<Object> provider, {
+    required String source,
+    required String kind,
+  }) async {
+    var failed = false;
+    try {
+      await precacheImage(
+        provider,
+        context,
+        onError: (_, _) {
+          failed = true;
+        },
+      );
+    } catch (_) {
+      failed = true;
+    }
+    if (failed) {
+      _log(
+        '[player-entry] phase=frame-precache-failed source=$source kind=$kind',
+      );
+    }
+    return !failed;
+  }
+
   static void _log(String message) {
     if (kDebugMode) debugPrint(message);
   }