valid layer checking added

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@85 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/qgisapp.cpp

@@ -92,8 +92,14 @@ void QgisApp::addLayer ()
       QgsShapeFileLayer *lyr = new QgsShapeFileLayer (*it, base);
       // give it a random color
 
-      // add it to the mapcanvas collection
-      mapCanvas->addLayer (lyr);
+      if(lyr->isValid()){
+	      // add it to the mapcanvas collection
+	      mapCanvas->addLayer (lyr);
+	      }else{
+	        QString msg = *it;
+	        msg += " is not a valid or recognized data source";
+	      	QMessageBox::critical(this,"Invalid Data Source",msg);
+	      }
 
       ++it;
     }

src/qgsmaplayer.cpp

@@ -102,3 +102,6 @@ void QgsMapLayer::setZ (int zorder)
 {
   zpos = zorder;
 }
+bool QgsMapLayer::isValid(){
+	return valid;
+	}

src/qgsshapefilelayer.cpp

@@ -44,15 +44,8 @@ QgsShapeFileLayer::QgsShapeFileLayer (QString vectorLayerPath, QString baseName)
       layerExtent.setXmin (ext->MinX);
       layerExtent.setYmax (ext->MaxY);
       layerExtent.setYmin (ext->MinY);
-/*			while(OGRFeature *fet = ogrLayer->GetNextFeature()){
-				fet->DumpReadable(stdout);
-				OGRGeometry *geom = fet->GetGeometryRef();
-				std::cout << geom->getGeometryName() << std::endl;
-				
-				delete fet;				
-			}
-	*/
-
+    }else{
+    	valid = false;
     }
 
 }