引导、通知栏计时

lib/screens/focus_screen.dart

@@ -24,21 +24,66 @@ class FocusScreen extends StatefulWidget {
   State<FocusScreen> createState() => _FocusScreenState();
 }
 
-class _FocusScreenState extends State<FocusScreen> {
+class _FocusScreenState extends State<FocusScreen> with WidgetsBindingObserver {
   late Timer _timer;
   late int _remainingSeconds;
   late DateTime _startTime;
   final List<String> _distractions = [];
   bool _isPaused = false;
+  bool _isInBackground = false;
+  final NotificationService _notificationService = NotificationService();
 
   @override
   void initState() {
     super.initState();
     _remainingSeconds = widget.durationMinutes * 60;
     _startTime = DateTime.now();
+    WidgetsBinding.instance.addObserver(this);
     _startTimer();
   }
 
+  @override
+  void dispose() {
+    WidgetsBinding.instance.removeObserver(this);
+    _timer.cancel();
+    // Cancel ongoing notification when leaving the screen
+    _notificationService.cancelOngoingFocusNotification();
+    super.dispose();
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    super.didChangeAppLifecycleState(state);
+
+    switch (state) {
+      case AppLifecycleState.paused:
+      case AppLifecycleState.inactive:
+      case AppLifecycleState.detached:
+        // App went to background
+        _isInBackground = true;
+        if (!_isPaused && _remainingSeconds > 0) {
+          _showBackgroundNotification();
+        }
+        break;
+      case AppLifecycleState.resumed:
+        // App came back to foreground
+        _isInBackground = false;
+        _notificationService.cancelOngoingFocusNotification();
+        break;
+      case AppLifecycleState.hidden:
+        break;
+    }
+  }
+
+  void _showBackgroundNotification() {
+    final minutes = _remainingSeconds ~/ 60;
+    final seconds = _remainingSeconds % 60;
+    _notificationService.showOngoingFocusNotification(
+      remainingMinutes: minutes,
+      remainingSeconds: seconds,
+    );
+  }
+
   void _startTimer() {
     _timer = Timer.periodic(const Duration(seconds: 1), (timer) {
       if (!_isPaused && _remainingSeconds > 0) {
@@ -46,6 +91,18 @@ class _FocusScreenState extends State<FocusScreen> {
           _remainingSeconds--;
         });
 
+        // Update background notification every 30 seconds when in background
+        if (_isInBackground && _remainingSeconds > 0) {
+          if (_remainingSeconds % 30 == 0) {
+            final minutes = _remainingSeconds ~/ 60;
+            final seconds = _remainingSeconds % 60;
+            _notificationService.updateOngoingFocusNotification(
+              remainingMinutes: minutes,
+              remainingSeconds: seconds,
+            );
+          }
+        }
+
         if (_remainingSeconds == 0) {
           _onTimerComplete();
         }
@@ -55,11 +112,14 @@ class _FocusScreenState extends State<FocusScreen> {
 
   void _onTimerComplete() async {
     _timer.cancel();
+
+    // Cancel ongoing notification and show completion notification
+    await _notificationService.cancelOngoingFocusNotification();
+
     _saveFocusSession(completed: true);
 
-    // Send notification
-    final notificationService = NotificationService();
-    await notificationService.showFocusCompletedNotification(
+    // Send completion notification
+    await _notificationService.showFocusCompletedNotification(
       minutes: widget.durationMinutes,
       distractionCount: _distractions.length,
     );
@@ -82,6 +142,13 @@ class _FocusScreenState extends State<FocusScreen> {
     setState(() {
       _isPaused = !_isPaused;
     });
+
+    // Update notification when paused
+    if (_isPaused && _isInBackground) {
+      _notificationService.cancelOngoingFocusNotification();
+    } else if (!_isPaused && _isInBackground) {
+      _showBackgroundNotification();
+    }
   }
 
   void _stopEarly() {
@@ -257,12 +324,6 @@ class _FocusScreenState extends State<FocusScreen> {
     return '${minutes.toString().padLeft(2, '0')}:${secs.toString().padLeft(2, '0')}';
   }
 
-  @override
-  void dispose() {
-    _timer.cancel();
-    super.dispose();
-  }
-
   @override
   Widget build(BuildContext context) {
     return Scaffold(