Make marker disappear when drones are cleared

drip-android-observer-master/Android/app/src/main/AndroidManifest.xml

@@ -7,7 +7,6 @@
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.INTERNET" />
-    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
     <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

drip-android-observer-master/Android/app/src/main/java/org/dripdronescanner/android/app/AircraftMapView.java

@@ -111,7 +111,8 @@ public class AircraftMapView extends Fragment {
 
         ImageButton centerMapButton = v.findViewById(R.id.ic_center_map);
         centerMapButton.setOnClickListener(v12 -> {
-            map.getController().animateTo(overlay.getMyLocation());
+            if (overlay != null)
+                map.getController().animateTo(overlay.getMyLocation());
         });
 
         return v;
@@ -159,9 +160,9 @@ public class AircraftMapView extends Fragment {
                 Log.i(TAG, "centering on " + object + " at " + loc.getLatitude() + " " + loc.getLongitude());
 
                 if (last != null && last.marker != null) {
-                    last.marker.setAlpha(0.5f);
+                    last.marker.setAlpha(0.8f);
                     if (last.markerPilot != null)
-                        last.markerPilot.setAlpha(0.5f);
+                        last.markerPilot.setAlpha(0.8f);
                 }
                 if (observer.marker != null)
                     observer.marker.setAlpha(1.0f);
@@ -209,19 +210,21 @@ public class AircraftMapView extends Fragment {
         void stop() {
             aircraft.location.removeObserver(this);
             aircraft.system.removeObserver(systemObserver);
+
             if (marker != null) {
-                marker.setAlpha(0.0f); // TODO: This is a temporary fix to make sure the marker disappears.
                 map.getOverlays().remove(marker);
                 marker = null;
+                map.invalidate();
             }
             if (markerPilot != null) {
-                markerPilot.setAlpha(0.0f); // TODO
                 map.getOverlays().remove(markerPilot);
                 markerPilot = null;
+                map.invalidate();
             }
             if (polyline != null) {
                 map.getOverlays().remove(polyline);
                 polyline = null;
+                map.invalidate();
             }
         }
 
@@ -245,11 +248,11 @@ public class AircraftMapView extends Fragment {
                     markerPilot.setPosition(new GeoPoint(sys.getOperatorLatitude(), sys.getOperatorLongitude()));
                     markerPilot.setIcon(ResourcesCompat.getDrawable(getResources(), R.drawable.ic_pilot, null));
                     markerPilot.setTitle("pilot " + id);
-                    markerPilot.setAlpha(0.5f);
+                    markerPilot.setAlpha(0.8f);
                     markerPilot.setRelatedObject(aircraft);
                     markerPilot.setOnMarkerClickListener(onMarkerClick);
+                    map.getOverlays().add(markerPilot);
                 }
-                map.getOverlays().add(markerPilot);
             }
         };
 
@@ -273,16 +276,17 @@ public class AircraftMapView extends Fragment {
                 marker.setPosition(new GeoPoint(loc.getLatitude(), loc.getLongitude()));
                 marker.setIcon(ResourcesCompat.getDrawable(getResources(), R.drawable.ic_airplan, null));
                 marker.setTitle("aircraft " + id);
-                marker.setAlpha(0.5f);
+                marker.setAlpha(0.8f);
                 marker.setRelatedObject(aircraft);
                 marker.setOnMarkerClickListener(onMarkerClick);
                 zoom = true;
+                map.getOverlays().add(marker);
             }
-            map.getOverlays().add(marker);
 
             if (polyline != null) {
                 map.getOverlays().remove(polyline);
                 polyline = null;
+                map.invalidate();
             }
 
             polyline = new Polyline();

drip-android-observer-master/Android/app/src/main/java/org/dripdronescanner/android/app/DeviceList.java

@@ -110,6 +110,8 @@ public class DeviceList extends Fragment {
                     // only set if different
                     mModel.setActiveAircraft(item.object);
                 }
+            } else {
+                mModel.setActiveAircraft(null);
             }
         });
         RecyclerView mRecyclerView = viewGroup.findViewById(R.id.device_list);

drip-android-observer-master/Android/app/src/main/java/org/dripdronescanner/android/app/SettingsActivity.java

@@ -35,7 +35,7 @@ public class SettingsActivity extends AppCompatActivity {
                 SharedPreferences.Editor editor = sharedPreferences.edit();
 
                 editor.putString("url",tv.getText().toString());
-                editor.commit();
+                editor.apply();
             }
         });
     }