Fix Bug cursor empty and map not initialized

app/src/main/java/fr/mobdev/blooddonation/Database.java

@@ -477,8 +477,9 @@ public class Database extends SQLiteOpenHelper {
         columns[0] = "latitude";
         columns[1] = "longitude";
         Cursor cursor = getReadableDatabase().query("user",columns,null,null,null,null,null);
-        cursor.moveToFirst();
-        LatLng loc = new LatLng(cursor.getDouble(0),cursor.getDouble(1));
+        LatLng loc = new LatLng(0,0);
+        if(cursor.moveToFirst())
+            loc = new LatLng(cursor.getDouble(0),cursor.getDouble(1));
         cursor.close();
         return loc;
     }

app/src/main/java/fr/mobdev/blooddonation/fragment/MapsFragment.java

@@ -419,6 +419,8 @@ public class MapsFragment extends Fragment implements OnMapReadyCallback {
     }
 
     private LatLng getCorner(CORNER corner) {
+        if(map == null)
+            return new LatLng(0,0);
         com.car2go.maps.Projection pr = map.getProjection();
         LatLngBounds bounds = pr.getVisibleRegion().latLngBounds;
         if(corner == CORNER.TOP_RIGHT)