引导、通知栏计时

lib/services/notification_service.dart

@@ -189,6 +189,88 @@ class NotificationService {
     }
   }
 
+  /// Cancel a specific notification by ID
+  Future<void> cancel(int id) async {
+    if (kIsWeb || !_initialized) return;
+
+    try {
+      await _notifications.cancel(id);
+    } catch (e) {
+      if (kDebugMode) {
+        print('Failed to cancel notification $id: $e');
+      }
+    }
+  }
+
+  /// Show ongoing focus session notification (for background)
+  /// This notification stays visible while the timer is running
+  Future<void> showOngoingFocusNotification({
+    required int remainingMinutes,
+    required int remainingSeconds,
+  }) async {
+    if (kIsWeb || !_initialized) return;
+
+    try {
+      // Format time display
+      final timeStr = '${remainingMinutes.toString().padLeft(2, '0')}:${(remainingSeconds % 60).toString().padLeft(2, '0')}';
+
+      const androidDetails = AndroidNotificationDetails(
+        'focus_timer',
+        'Focus Timer',
+        channelDescription: 'Shows ongoing focus session timer',
+        importance: Importance.low,
+        priority: Priority.low,
+        ongoing: true, // Makes notification persistent
+        autoCancel: false,
+        showWhen: false,
+        enableVibration: false,
+        playSound: false,
+        // Show in status bar
+        showProgress: false,
+      );
+
+      const iosDetails = DarwinNotificationDetails(
+        presentAlert: true,
+        presentBadge: false,
+        presentSound: false,
+      );
+
+      const notificationDetails = NotificationDetails(
+        android: androidDetails,
+        iOS: iosDetails,
+      );
+
+      await _notifications.show(
+        2, // Use ID 2 for ongoing notifications
+        '⏱️ Focus session in progress',
+        '$timeStr remaining',
+        notificationDetails,
+        payload: 'focus_ongoing',
+      );
+    } catch (e) {
+      if (kDebugMode) {
+        print('Failed to show ongoing notification: $e');
+      }
+    }
+  }
+
+  /// Update ongoing notification with new time
+  Future<void> updateOngoingFocusNotification({
+    required int remainingMinutes,
+    required int remainingSeconds,
+  }) async {
+    // On Android, showing the same notification ID updates it
+    await showOngoingFocusNotification(
+      remainingMinutes: remainingMinutes,
+      remainingSeconds: remainingSeconds,
+    );
+  }
+
+  /// Cancel ongoing focus notification
+  Future<void> cancelOngoingFocusNotification() async {
+    await cancel(2); // Cancel notification with ID 2
+  }
+
   /// Check if notifications are supported on this platform
   bool get isSupported => !kIsWeb;
 }