fix the bug in case of non-supported level

src/QtLocationPlugin/QGCMapUrlEngine.cpp

@@ -147,8 +147,9 @@ UrlFactory::getTileURL(MapType type, int x, int y, int zoom, QNetworkAccessManag
     //-- Build URL
     QNetworkRequest request;
     QString url = _getURL(type, x, y, zoom, networkManager);
-    if(url.isEmpty())
+    if(url.isEmpty()) {
         return request;
+    }
     request.setUrl(QUrl(url));
     request.setRawHeader("Accept", "*/*");
     switch (type) {
@@ -433,7 +434,10 @@ UrlFactory::_getURL(MapType type, int x, int y, int zoom, QNetworkAccessManager*
         int y_min = 22 * pow(2, gap);
         int y_max = 26 * pow(2, gap) + (2*gap - 1);
 
-        if ( zoom > 5 && x >= x_min && x <= x_max && y >= y_min && y <= y_max ) {
+        if ( zoom > 19 ) {
+            return QString("");
+        }
+        else if ( zoom > 5 && x >= x_min && x <= x_max && y >= y_min && y <= y_max ) {
             return QString("http://xdworld.vworld.kr:8080/2d/Base/service/%1/%2/%3.png").arg(zoom).arg(x).arg(y);
         }
         else {
@@ -453,7 +457,10 @@ UrlFactory::_getURL(MapType type, int x, int y, int zoom, QNetworkAccessManager*
         int y_min = 22 * pow(2, gap);
         int y_max = 26 * pow(2, gap) + (2*gap - 1);
 
-        if ( zoom > 5 && x >= x_min && x <= x_max && y >= y_min && y <= y_max ) {
+        if ( zoom > 19 ) {
+            return QString("");
+        }
+        else if ( zoom > 5 && x >= x_min && x <= x_max && y >= y_min && y <= y_max ) {
             return QString("http://xdworld.vworld.kr:8080/2d/Satellite/service/%1/%2/%3.jpeg").arg(zoom).arg(x).arg(y);
         }
         else {

src/QtLocationPlugin/QGeoTileFetcherQGC.cpp

@@ -75,7 +75,12 @@ QGeoTileFetcherQGC::getTileImage(const QGeoTileSpec &spec)
 {
     //-- Build URL
     QNetworkRequest request = getQGCMapEngine()->urlFactory()->getTileURL((UrlFactory::MapType)spec.mapId(), spec.x(), spec.y(), spec.zoom(), _networkManager);
+    if ( ! request.url().isEmpty() ) {
         return new QGeoTiledMapReplyQGC(_networkManager, request, spec);
+    }
+    else {
+        return NULL;
+    }
 }
 
 //-----------------------------------------------------------------------------