[layertree] Doxygen docs for QgsLayerTreeView

Author: wonder-sk

src/gui/layertree/qgslayertreeview.cpp

@@ -87,6 +87,12 @@ QgsMapLayer* QgsLayerTreeView::currentLayer() const
 
 void QgsLayerTreeView::setCurrentLayer( QgsMapLayer* layer )
 {
+  if ( !layer )
+  {
+    setCurrentIndex( QModelIndex() );
+    return;
+  }
+
   QgsLayerTreeLayer* nodeLayer = layerTreeModel()->rootGroup()->findLayer( layer->id() );
   if ( !nodeLayer )
     return;

src/gui/layertree/qgslayertreeview.h

@@ -26,47 +26,76 @@ class QgsLayerTreeViewDefaultActions;
 class QgsLayerTreeViewMenuProvider;
 class QgsMapLayer;
 
+/**
+ * The QgsLayerTreeView class extends QTreeView and provides some additional functionality
+ * when working with a layer tree.
+ *
+ * The view updates expanded state of layer tree nodes and also listens to changes
+ * to expanded states in the layer tree.
+ *
+ * The view keeps track of the current layer and emits a signal when the current layer has changed.
+ *
+ * Allows the client to specify a context menu provider with custom actions. Also it comes
+ * with a set of default actions that can be used when building context menu.
+ *
+ * @see QgsLayerTreeModel
+ * @note added in 2.4
+ */
 class GUI_EXPORT QgsLayerTreeView : public QTreeView
 {
     Q_OBJECT
   public:
     explicit QgsLayerTreeView( QWidget *parent = 0 );
     ~QgsLayerTreeView();
 
+    //! Overridden setModel() from base class. Only QgsLayerTreeModel is an acceptable model.
     virtual void setModel( QAbstractItemModel* model );
 
+    //! Get access to the model casted to QgsLayerTreeModel
     QgsLayerTreeModel* layerTreeModel() const;
 
+    //! Get access to the default actions that may be used with the tree view
     QgsLayerTreeViewDefaultActions* defaultActions();
 
-    void setMenuProvider( QgsLayerTreeViewMenuProvider* menuProvider ); // takes ownership
+    //! Set provider for context menu. Takes ownership of the instance
+    void setMenuProvider( QgsLayerTreeViewMenuProvider* menuProvider );
+    //! Return pointer to the context menu provider. May be null
     QgsLayerTreeViewMenuProvider* menuProvider() const { return mMenuProvider; }
 
+    //! Get currently selected layer. May be null
     QgsMapLayer* currentLayer() const;
+    //! Set currently selected layer. Null pointer will deselect any layer.
     void setCurrentLayer( QgsMapLayer* layer );
 
+    //! Get current node. May be null
     QgsLayerTreeNode* currentNode() const;
+    //! Get current group node. If a layer is current node, the function will return parent group. May be null.
     QgsLayerTreeGroup* currentGroupNode() const;
 
+    //! Return list of selected nodes
+    //! @arg skipInternal If true, will ignore nodes which have an ancestor in the selection
     QList<QgsLayerTreeNode*> selectedNodes( bool skipInternal = false ) const;
+    //! Return list of selected nodes filtered to just layer nodes
     QList<QgsLayerTreeLayer*> selectedLayerNodes() const;
 
+    //! Get list of selected layers
     QList<QgsMapLayer*> selectedLayers() const;
 
   public slots:
+    //! Force refresh of layer symbology. Normally not needed as the changes of layer's renderer are monitored by the model
     void refreshLayerSymbology( const QString& layerId );
 
+  signals:
+    //! Emitted when a current layer is changed
+    void currentLayerChanged( QgsMapLayer* layer );
+
   protected:
     void contextMenuEvent( QContextMenuEvent* event );
 
     void updateExpandedStateFromNode( QgsLayerTreeNode* node );
 
     QgsMapLayer* layerForIndex( const QModelIndex& index ) const;
 
-  signals:
-    void currentLayerChanged( QgsMapLayer* layer );
-
-
   protected slots:
 
     void modelRowsInserted( QModelIndex index, int start, int end );
@@ -77,17 +106,28 @@ class GUI_EXPORT QgsLayerTreeView : public QTreeView
     void onCurrentChanged();
 
   protected:
+    //! helper class with default actions. Lazily initialized.
     QgsLayerTreeViewDefaultActions* mDefaultActions;
+    //! Context menu provider. Owned by the view.
     QgsLayerTreeViewMenuProvider* mMenuProvider;
+    //! Keeps track of current index (to check when to emit signal about change of current layer)
     QPersistentModelIndex mCurrentIndex;
 };
 
-/** interface to allow custom menus */
+
+/**
+ * Implementation of this interface can be implemented to allow QgsLayerTreeView
+ * instance to provide custom context menus (opened upon right-click).
+ *
+ * @see QgsLayerTreeView
+ * @note added in 2.4
+ */
 class GUI_EXPORT QgsLayerTreeViewMenuProvider
 {
   public:
     virtual ~QgsLayerTreeViewMenuProvider() {}
 
+    //! Return a newly created menu instance (or null pointer on error)
     virtual QMenu* createContextMenu() = 0;
 };