Fixes #929. Only enable copy/cut action when there is a selection, and only enable paste action when there is something in the clipboard.

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@9551 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: homann

src/app/qgisapp.cpp

@@ -1498,6 +1498,8 @@ void QgisApp::setupConnections()
   connect( mMapCanvas, SIGNAL( scaleChanged( double ) ), this, SLOT( showScale( double ) ) );
   connect( mMapCanvas, SIGNAL( scaleChanged( double ) ), this, SLOT( updateMouseCoordinatePrecision() ) );
   connect( mMapCanvas, SIGNAL( mapToolSet( QgsMapTool * ) ), this, SLOT( mapToolChanged( QgsMapTool * ) ) );
+  connect( mMapCanvas, SIGNAL( selectionChanged( QgsMapLayer * ) ),
+           this, SLOT( activateDeactivateLayerRelatedActions( QgsMapLayer * ) ) );
 
   connect( mRenderSuppressionCBox, SIGNAL( toggled( bool ) ), mMapCanvas, SLOT( setRenderFlag( bool ) ) );
   //
@@ -5029,16 +5031,17 @@ void QgisApp::activateDeactivateLayerRelatedActions( QgsMapLayer* layer )
   /***********Vector layers****************/
   if ( layer->type() == QgsMapLayer::VectorLayer )
   {
+    QgsVectorLayer* vlayer = dynamic_cast<QgsVectorLayer*>( layer );
+    const QgsVectorDataProvider* dprovider = vlayer->dataProvider();
+    bool layerHasSelection = ( vlayer->selectedFeatureCount() != 0 );
+
     mActionSelect->setEnabled( true );
     mActionIdentify->setEnabled( true );
     mActionZoomActualSize->setEnabled( false );
     mActionOpenTable->setEnabled( true );
     mActionLayerSaveAs->setEnabled( true );
     mActionLayerSelectionSaveAs->setEnabled( true );
-    mActionCopyFeatures->setEnabled( true );
-
-    const QgsVectorLayer* vlayer = dynamic_cast<const QgsVectorLayer*>( layer );
-    const QgsVectorDataProvider* dprovider = vlayer->dataProvider();
+    mActionCopyFeatures->setEnabled( layerHasSelection );
 
     if ( !vlayer->isEditable() && mMapCanvas->mapTool() && mMapCanvas->mapTool()->isEditTool() )
     {
@@ -5052,7 +5055,7 @@ void QgisApp::activateDeactivateLayerRelatedActions( QgsMapLayer* layer )
       {
         mActionToggleEditing->setEnabled( true );
         mActionToggleEditing->setChecked( vlayer->isEditable() );
-        mActionPasteFeatures->setEnabled( vlayer->isEditable() );
+        mActionPasteFeatures->setEnabled( vlayer->isEditable() and not clipboard()->empty());
       }
       else
       {
@@ -5063,8 +5066,8 @@ void QgisApp::activateDeactivateLayerRelatedActions( QgsMapLayer* layer )
       //does provider allow deleting of features?
       if ( vlayer->isEditable() && dprovider->capabilities() & QgsVectorDataProvider::DeleteFeatures )
       {
-        mActionDeleteSelected->setEnabled( true );
-        mActionCutFeatures->setEnabled( true );
+        mActionDeleteSelected->setEnabled( layerHasSelection );
+        mActionCutFeatures->setEnabled( layerHasSelection );
       }
       else
       {

src/app/qgsclipboard.cpp

@@ -135,3 +135,7 @@ void QgsClipboard::insert( QgsFeature& feature )
   QgsDebugMsg( "inserted " + feature.geometry()->exportToWkt() );
 }
 
+bool QgsClipboard::empty()
+{
+  return mFeatureClipboard.empty();
+}

src/app/qgsclipboard.h

@@ -84,6 +84,11 @@ class QgsClipboard
     void insert( QgsFeature& feature );
 
 
+    /*
+     *  Returns true if the internal clipboard is empty, else false.
+     */
+    bool empty();
+
   private:
 
     /** QGIS-internal vector feature clipboard.

src/gui/qgsmapcanvas.cpp

@@ -259,7 +259,7 @@ void QgsMapCanvas::setLayerSet( QList<QgsMapCanvasLayer>& layers )
       QgsVectorLayer *isVectLyr = dynamic_cast < QgsVectorLayer * >( currentLayer );
       if ( isVectLyr )
       {
-        disconnect( currentLayer, SIGNAL( selectionChanged() ), this, SLOT( refresh() ) );
+        disconnect( currentLayer, SIGNAL( selectionChanged() ), this, SLOT( selectionChangedSlot() ) );
       }
     }
 
@@ -275,7 +275,7 @@ void QgsMapCanvas::setLayerSet( QList<QgsMapCanvasLayer>& layers )
       QgsVectorLayer *isVectLyr = dynamic_cast < QgsVectorLayer * >( currentLayer );
       if ( isVectLyr )
       {
-        connect( currentLayer, SIGNAL( selectionChanged() ), this, SLOT( refresh() ) );
+        connect( currentLayer, SIGNAL( selectionChanged() ), this, SLOT(  selectionChangedSlot() ) );
       }
     }
   }
@@ -1278,3 +1278,11 @@ void QgsMapCanvas::zoom( double scaleFactor )
   refresh();
 }
 
+void QgsMapCanvas::selectionChangedSlot()
+{
+  // Find out which layer it was that sent the signal.
+  QgsMapLayer * layer = ( QgsMapLayer * )QObject::sender();
+  
+  emit selectionChanged( layer );
+  refresh();
+}

src/gui/qgsmapcanvas.h

@@ -240,6 +240,9 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     /**Repaints the canvas map*/
     void refresh();
 
+    //! Receives signal about selection change, and pass it on with layer info
+    void selectionChangedSlot();
+
     //! Save the convtents of the map canvas to disk as an image
     void saveAsImage( QString theFileName, QPixmap * QPixmap = 0, QString = "PNG" );
 
@@ -301,7 +304,10 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     void keyReleased( QKeyEvent * e );
 
     //! Emit map tool changed event
-    void mapToolSet( QgsMapTool *tool );
+    void mapToolSet( QgsMapTool * tool );
+
+    //! Emit map tool changed event
+    void selectionChanged( QgsMapLayer * layer );
 
   protected:
     //! Overridden key press event