Bugfix: NPE fixed because listeners/client were null in some cases.

TrackRecordingService: before destroying it sends GPS Status NONE to all listeners.
Cleanup Logs used for debugging.

src/main/java/de/dennisguse/opentracks/TrackRecordingActivity.java

@@ -94,16 +94,6 @@ public class TrackRecordingActivity extends AbstractActivity implements ChooseAc
                 trackController.update(true, false);
                 trackController.onResume(true, recordingTrackPaused);
             }
-            service.addListener(new TrackRecordingServiceCallback() {
-                @Override
-                public void onGpsStatusChange(GpsStatusValue newStatus) {
-                    // TODO 2020-07-17 Add some visible View in the Layout to inform about this and then delete the Toast message.
-                    // Inform through Toast the bad news: GPS is not fixed.
-                    if (newStatus == GpsStatusValue.GPS_NONE || newStatus == GpsStatusValue.GPS_DISABLED || newStatus == GpsStatusValue.GPS_SIGNAL_LOST) {
-                        Toast.makeText(getApplicationContext(), getString(newStatus.message), Toast.LENGTH_LONG).show();
-                    }
-                }
-            });
         }
     };
 

src/main/java/de/dennisguse/opentracks/services/TrackRecordingService.java

@@ -158,14 +158,17 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
 
     @Override
     public void onDestroy() {
-        handlerServer.stop(this);
-        handlerServer = null;
-
         if (listeners != null) {
+            for (TrackRecordingServiceCallback listener : listeners) {
+                listener.onGpsStatusChange(GpsStatusValue.GPS_NONE);
+            }
             listeners.clear();
             listeners = null;
         }
 
+        handlerServer.stop(this);
+        handlerServer = null;
+
         if (remoteSensorManager != null) {
             remoteSensorManager.stop();
             remoteSensorManager = null;
@@ -595,9 +598,11 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
 
     @Override
     public void newGpsStatus(GpsStatusValue gpsStatusValue) {
-        notificationManager.updateContent(getString(gpsStatusValue.message));
+        if (listeners != null) {
-        for (TrackRecordingServiceCallback listener : listeners) {
+            notificationManager.updateContent(getString(gpsStatusValue.message));
-            listener.onGpsStatusChange(gpsStatusValue);
+            for (TrackRecordingServiceCallback listener : listeners) {
+                listener.onGpsStatusChange(gpsStatusValue);
+            }
         }
     }
 

src/main/java/de/dennisguse/opentracks/services/handlers/GpsStatus.java

@@ -4,7 +4,6 @@ import android.content.Context;
 import android.location.Location;
 import android.location.LocationManager;
 import android.os.Handler;
-import android.util.Log;
 
 import de.dennisguse.opentracks.util.PreferencesUtils;
 import de.dennisguse.opentracks.util.UnitConversions;
@@ -12,13 +11,12 @@ import de.dennisguse.opentracks.util.UnitConversions;
 /**
  * This class handle GPS status according to received locations and some thresholds.
  */
-// TODO 2020-07-17 Delete all Log.d messages before merge with main branch. For now it's useful for debugging.
 class GpsStatus {
 
     private static final String TAG = GpsStatus.class.getSimpleName();
 
     // The quantity of milliseconds that GpsStatus waits from minimal interval to consider GPS lost.
-    private static final int SIGNAL_LOST_THRESHOLD = 10000;
+    private static final int SIGNAL_LOST_THRESHOLD = (int) (10 * UnitConversions.S_TO_MS);
 
     // Threshold for accuracy.
     private double signalBadThreshold;
@@ -28,7 +26,10 @@ class GpsStatus {
     private GpsStatusValue gpsStatus = GpsStatusValue.GPS_NONE;
     private GpsStatusListener client;
     private Context context;
+
+    // Last location. It can be null.
     private Location lastLocation = null;
+    // The last valid (not null) location. Null value means that there have not been any location yet.
     private Location lastValidLocation = null;
 
     private class GpsStatusRunner implements Runnable {
@@ -67,10 +68,10 @@ class GpsStatus {
      * The client that uses GpsStatus has to call this method to stop the Runnable if needed.
      */
     public void stop() {
+        client = null;
         if (gpsStatusRunner != null) {
             gpsStatusRunner.stop();
             gpsStatusRunner = null;
-            client = null;
         }
     }
 
@@ -119,24 +120,21 @@ class GpsStatus {
     private void checkStatusFromLastLocation() {
         if (System.currentTimeMillis() - lastLocation.getTime() > signalLostThreshold && gpsStatus != GpsStatusValue.GPS_SIGNAL_LOST) {
             // So much time without receiving signal -> signal lost.
-            Log.d(TAG, "Signal LOST. signalLostThreshold: " + signalLostThreshold + " - System.currentTimeMillis() - lastLocation.getTime() > " + (System.currentTimeMillis() - lastLocation.getTime()));
             GpsStatusValue oldStatus = gpsStatus;
             gpsStatus = GpsStatusValue.GPS_SIGNAL_LOST;
-            client.onGpsStatusChanged(oldStatus, gpsStatus);
+            sendStatus(oldStatus, gpsStatus);
             stopStatusRunner();
         } else if (lastLocation.getAccuracy() > signalBadThreshold && gpsStatus != GpsStatusValue.GPS_SIGNAL_BAD) {
             // Too little accuracy -> bad signal.
-            Log.d(TAG, "Signal BAD. signalBadThreshold: " + signalBadThreshold + " - lastLocation.getAccuracy() = " + lastLocation.getAccuracy());
             GpsStatusValue oldStatus = gpsStatus;
             gpsStatus = GpsStatusValue.GPS_SIGNAL_BAD;
-            client.onGpsStatusChanged(oldStatus, gpsStatus);
+            sendStatus(oldStatus, gpsStatus);
             startStatusRunner();
         } else if (lastLocation.getAccuracy() <= signalBadThreshold && gpsStatus != GpsStatusValue.GPS_SIGNAL_FIX) {
-            Log.d(TAG, "Signal FIX. signalBadThreshold: " + signalBadThreshold + " - lastLocation.getAccuracy() = " + lastLocation.getAccuracy());
             // Gps okay.
             GpsStatusValue oldStatus = gpsStatus;
             gpsStatus = GpsStatusValue.GPS_SIGNAL_FIX;
-            client.onGpsStatusChanged(oldStatus, gpsStatus);
+            sendStatus(oldStatus, gpsStatus);
             startStatusRunner();
         }
     }
@@ -149,10 +147,9 @@ class GpsStatus {
     private void checkStatusFromLastValidLocation() {
         if (System.currentTimeMillis() - lastValidLocation.getTime() > signalLostThreshold) {
             // Too much time without locations -> lost signal? (wait signalLostThreshold from last valid location).
-            Log.d(TAG, "Signal LOST. signalLostThreshold: " + signalLostThreshold + " - System.currentTimeMillis() - lastValidLocation.getTime() > " + signalLostThreshold);
             GpsStatusValue oldStatus = gpsStatus;
             gpsStatus = GpsStatusValue.GPS_SIGNAL_LOST;
-            client.onGpsStatusChanged(oldStatus, gpsStatus);
+            sendStatus(oldStatus, gpsStatus);
             stopStatusRunner();
             lastValidLocation = null;
         }
@@ -168,7 +165,7 @@ class GpsStatus {
             if (locationManager != null && locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
                 GpsStatusValue oldStatus = gpsStatus;
                 gpsStatus = GpsStatusValue.GPS_ENABLED;
-                client.onGpsStatusChanged(oldStatus, gpsStatus);
+                sendStatus(oldStatus, gpsStatus);
                 startStatusRunner();
             } else {
                 onGpsDisabled();
@@ -183,13 +180,19 @@ class GpsStatus {
         if (gpsStatus != GpsStatusValue.GPS_DISABLED) {
             GpsStatusValue oldStatus = gpsStatus;
             gpsStatus = GpsStatusValue.GPS_DISABLED;
-            client.onGpsStatusChanged(oldStatus, gpsStatus);
+            sendStatus(oldStatus, gpsStatus);
             lastLocation = null;
             lastValidLocation = null;
             stopStatusRunner();
         }
     }
 
+    private void sendStatus(GpsStatusValue prev, GpsStatusValue current) {
+        if (client != null) {
+            client.onGpsStatusChanged(prev, current);
+        }
+    }
+
     private void startStatusRunner() {
         if (gpsStatusRunner == null) {
             gpsStatusRunner = new GpsStatusRunner();