Do not emit currentLayerChanged signal if the layer has not changed

wonder-sk · wonder-sk · commit 7e34bd901fda · 2014-02-14T16:08:43.000+07:00
diff --git a/src/app/legend/qgslegend.cpp b/src/app/legend/qgslegend.cpp
@@ -181,8 +181,9 @@ void QgsLegend::showItem( QString msg, QTreeWidgetItem *item )
 
 void QgsLegend::handleCurrentItemChanged( QTreeWidgetItem* current, QTreeWidgetItem* previous )
 {
-  Q_UNUSED( current );
-  Q_UNUSED( previous );
+  if ( legendLayerForItem( current ) == legendLayerForItem( previous ) )
+    return; // do not re-emit signal when not necessary
+
   QgsMapLayer *layer = currentLayer();
 
   if ( mMapCanvas )
@@ -1214,7 +1215,12 @@ void QgsLegend::setLayerVisible( QgsMapLayer * layer, bool visible )
 
 QgsLegendLayer* QgsLegend::currentLegendLayer()
 {
-  QgsLegendItem* citem = dynamic_cast<QgsLegendItem *>( currentItem() );
+  return legendLayerForItem( currentItem() );
+}
+
+QgsLegendLayer* QgsLegend::legendLayerForItem( QTreeWidgetItem* item )
+{
+  QgsLegendItem* citem = dynamic_cast<QgsLegendItem *>( item );
 
   if ( citem )
   {
diff --git a/src/app/legend/qgslegend.h b/src/app/legend/qgslegend.h
@@ -115,6 +115,9 @@ class QgsLegend : public QTreeWidget
     //! Destructor
     ~QgsLegend();
 
+    /** Returns QgsLegendLayer accosiated with given item */
+    QgsLegendLayer* legendLayerForItem( QTreeWidgetItem* item );
+
     /** Returns QgsLegendLayer associated with current layer */
     QgsLegendLayer* currentLegendLayer();
 
