added currentLayerChanged signal

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@5111 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: rblazek

src/legend/qgslegend.cpp

@@ -87,14 +87,16 @@ QgsLegend::~QgsLegend()
 
 void QgsLegend::handleCurrentItemChanged(QTreeWidgetItem* current, QTreeWidgetItem* previous)
 {
+  QgsMapLayer *layer = currentLayer();
   if(mApp)
     {
-      mApp->activateDeactivateLayerRelatedActions(currentLayer());
+      mApp->activateDeactivateLayerRelatedActions( layer );
     }
   if(mMapCanvas)
     {
-      mMapCanvas->setCurrentLayer(currentLayer());
+      mMapCanvas->setCurrentLayer( layer );
     }
+  emit currentLayerChanged ( layer );
 }   
 
 void QgsLegend::addGroup()

src/legend/qgslegend.h

@@ -327,5 +327,8 @@ this item may be moved back to the original position with resetToInitialPosition
 signals:
   void zOrderChanged(QgsLegend * lv);
 
+  //! Emited whenever current (selected) layer changes
+  //  the pointer to layer can be null if no layer is selected
+  void currentLayerChanged ( QgsMapLayer * layer );
 };
 #endif