当我进入地理围栏时，如何连续运行后台服务以发送推送通知？

Question

我的应用程序是关于任务管理的，我可以为特定任务分配位置。我将该位置的纬度和经度存储在数据库中。现在我想在用户当前位置周围创建运行时地理围栏，并检查存储的latlong是否存在于围栏中。如果存在，那么我想向用户发送通知，告知您您已将任务分配给该位置。

在我的主要活动中，我有create方法来从数据库中获取纬度值。获取当前位置并在其周围生成500m的地理围栏。检查数据库值和当前纬度值是否匹配，如果匹配则发送通知。为发送通知，我创建了后台服务。现在我的服务运行正常并连续发送通知，但是当我从历史记录中删除我的应用程序时，我没有收到Notification.I已尝试使用一个信号推送通知，但没有解决我的问题。 如果不打开我的应用程序，我们可以在后台连续检查这种情况并发送通知吗？ 在没有打开应用程序的背景下，我们可以访问sqlite数据库值吗？

                    private void startGeofence() {
      Log.i(TAG, "startGeofence()");
      LatLng latLng = new LatLng(latitude, longitude);
      Geofence geofence = createGeofence(latLng, GEOFENCE_RADIUS);
      GeofencingRequest geofenceRequest = createGeofenceRequest(geofence);
      arrayList = dataBaseHelper.getLatlongList();
      arrayList.removeAll(Arrays.asList(" ", null));
      arrayList.removeAll(Arrays.asList("", null));
      Log.d(TAG, "onStart: " + arrayList.toString());
      String lat = String.format("%.2f", latitude);
      //String lat = String.valueOf(latitude);
      for (int j = 0; j < arrayList.size(); j++) {

         String first = arrayList.get(j);
         String value = String.format("%.5s", first);
         if (!value.equals(lat)) {
            //addGeofence(geofenceRequest);

            } else {
               if (ActivityCompat.checkSelfPermission(this, 
       Manifest.permission.ACCESS_FINE_LOCATION) != 
       PackageManager.PERMISSION_GRANTED) {
                // TODO: Consider calling
                //    ActivityCompat#requestPermissions
                // here to request the missing permissions, and then 
       overriding
                //   public void onRequestPermissionsResult(int 
       requestCode, String[] permissions,
                //                                          int[] 
          grantResults)
                // to handle the case where the user grants the 
           permission. See the documentation
                // for ActivityCompat#requestPermissions for more details.
                return;
            }
            geofencingClient.addGeofences(createGeofenceRequest(geofence), 
              getGeofencePendingIntent())
                    .addOnSuccessListener(this, new 
            OnSuccessListener<Void>() {
                        @Override
                        public void onSuccess(Void aVoid) {
                            // Geofences added
                            Log.d(TAG, "onSuccess: successfully added");
                            getGeofencePendingIntent();
                            // ...
                        }
                    })
                    .addOnFailureListener(this, new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            // Failed to add geofences
                            // ...
                        }
                    });

                    }
                  }


             }

       private PendingIntent getGeofencePendingIntent() {
             // Reuse the PendingIntent if we already have it.
      if (geoFencePendingIntent != null) {
        return geoFencePendingIntent;
     }
           Intent intent = new Intent(this, 
       GeofenceTrasitionService.class);
            // We use FLAG_UPDATE_CURRENT so that we get the same pending 
            intent 
         back when
    // calling addGeofences() and removeGeofences().
      geoFencePendingIntent = PendingIntent.getService(this, 0, intent, 
             PendingIntent.
            FLAG_UPDATE_CURRENT);
        return geoFencePendingIntent;
             }



                if (intent != null) {
                    GeofencingEvent geofencingEvent = 
                 GeofencingEvent.fromIntent(intent);

                       // Handling errors
                         if ( geofencingEvent.hasError() ) {
            String errorMsg = 
             getErrorString(geofencingEvent.getErrorCode() );
            Log.e( TAG, errorMsg );
            return;
             }

         // Retrieve GeofenceTrasition
         int geoFenceTransition = geofencingEvent.getGeofenceTransition();
         // Check if the transition type
         if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_ENTER ||
                 geoFenceTransition == Geofence.GEOFENCE_TRANSITION_EXIT ) 
                  {
            // Get the geofence that were triggered
             List<Geofence> triggeringGeofences = 
                 geofencingEvent.getTriggeringGeofences();
            // Create a detail message with Geofences received
            String geofenceTransitionDetails = 
           getGeofenceTrasitionDetails(geoFenceTransition, 
             triggeringGeofences );
            // Send notification details as a String
             try {
                OneSignal.postNotification(new JSONObject("{'contents': 
            {'en':'Test Message'}, 'include_player_ids': ['" + playerId + 
           "']}"), null);
            } catch (JSONException e) {
                e.printStackTrace();
            }
            Log.d(TAG, "onHandleIntent: Send Notification");
            //sendNotification( geofenceTransitionDetails );
                  }

在后台连续检查数据库位置和当前位置（如果当前位置中存在数据库位置），如果我从历史记录中删除了应用程序，围栏也会发送通知。