[layertree] Fix #10449 (auto-collapse layer if symbology has >= 10 items)

Author: wonder-sk

python/gui/layertree/qgslayertreemodel.sip

@@ -100,6 +100,11 @@ class QgsLayerTreeModel : QAbstractItemModel
     //! Get font for a particular type of layer tree node. nodeType should come from QgsLayerTreeNode::NodeType enumeration
     QFont layerTreeNodeFont( int nodeType ) const;
 
+    //! Set at what number of symbology nodes the layer node should be collapsed. Setting -1 disables the auto-collapse (default).
+    void setAutoCollapseSymbologyNodes( int nodeCount );
+    //! Return at what number of symbology nodes the layer node should be collapsed. -1 means no auto-collapse (default).
+    int autoCollapseSymbologyNodes() const;
+
   signals:
 
 };

src/app/qgisapp.cpp

@@ -2300,6 +2300,7 @@ void QgisApp::initLayerTreeView()
   model->setFlag( QgsLayerTreeModel::AllowNodeReorder );
   model->setFlag( QgsLayerTreeModel::AllowNodeRename );
   model->setFlag( QgsLayerTreeModel::AllowNodeChangeVisibility );
+  model->setAutoCollapseSymbologyNodes( 10 );
 
   mLayerTreeView->setModel( model );
   mLayerTreeView->setMenuProvider( new QgsAppLayerTreeViewMenuProvider( mLayerTreeView, mMapCanvas ) );

src/core/layertree/qgslayertreegroup.cpp

@@ -214,15 +214,18 @@ void QgsLayerTreeGroup::writeXML( QDomElement& parentElement )
 
 void QgsLayerTreeGroup::readChildrenFromXML( QDomElement& element )
 {
+  QList<QgsLayerTreeNode*> nodes;
   QDomElement childElem = element.firstChildElement();
   while ( !childElem.isNull() )
   {
     QgsLayerTreeNode* newNode = QgsLayerTreeNode::readXML( childElem );
     if ( newNode )
-      addChildNode( newNode );
+      nodes << newNode;
 
     childElem = childElem.nextSiblingElement();
   }
+
+  insertChildNodes( -1, nodes );
 }
 
 QString QgsLayerTreeGroup::dump() const

src/core/layertree/qgslayertreenode.cpp

@@ -110,6 +110,9 @@ void QgsLayerTreeNode::writeCommonXML( QDomElement& element )
 
 void QgsLayerTreeNode::insertChildrenPrivate( int index, QList<QgsLayerTreeNode*> nodes )
 {
+  if ( nodes.count() == 0 )
+    return;
+
   foreach ( QgsLayerTreeNode* node, nodes )
   {
     Q_ASSERT( node->mParent == 0 );

src/core/layertree/qgslayertreenode.h

@@ -51,6 +51,7 @@ class QDomElement;
  * file. The storage is not efficient for large amount of data.
  *
  * Custom properties that have already been used within QGIS:
+ * - "loading" - whether the project is being currently loaded (root node only)
  * - "overview" - whether to show a layer in overview
  * - "showFeatureCount" - whether to show feature counts in layer tree (vector only)
  * - "embedded" - whether the node comes from an external project

src/core/qgsproject.cpp

@@ -903,6 +903,8 @@ bool QgsProject::read()
 
   // read the layer tree from project file
 
+  mRootGroup->setCustomProperty( "loading", 1 );
+
   QDomElement layerTreeElem = doc->documentElement().firstChildElement( "layer-tree-group" );
   if ( !layerTreeElem.isNull() )
   {
@@ -945,6 +947,8 @@ bool QgsProject::read()
   // make sure the are just valid layers
   QgsLayerTreeUtils::removeInvalidLayers( mRootGroup );
 
+  mRootGroup->removeCustomProperty( "loading" );
+
   // read the project: used by map canvas and legend
   emit readProject( *doc );
 

src/gui/layertree/qgslayertreemodel.cpp

@@ -32,6 +32,7 @@ QgsLayerTreeModel::QgsLayerTreeModel( QgsLayerTreeGroup* rootNode, QObject *pare
     : QAbstractItemModel( parent )
     , mRootNode( rootNode )
     , mFlags( ShowSymbology )
+    , mAutoCollapseSymNodesCount( -1 )
 {
   Q_ASSERT( mRootNode );
 
@@ -429,11 +430,17 @@ void QgsLayerTreeModel::refreshLayerSymbology( QgsLayerTreeLayer* nodeLayer )
   emit dataChanged( idx, idx );
 
   // update children
-  beginRemoveRows( idx, 0, rowCount( idx ) - 1 );
+  int oldNodeCount = rowCount( idx );
+  beginRemoveRows( idx, 0, oldNodeCount - 1 );
   removeSymbologyFromLayer( nodeLayer );
   endRemoveRows();
 
   addSymbologyToLayer( nodeLayer );
+  int newNodeCount = rowCount( idx );
+
+  // automatic collapse of symbology nodes - useful if a layer has many symbology nodes
+  if ( mAutoCollapseSymNodesCount != -1 && oldNodeCount != newNodeCount && newNodeCount >= mAutoCollapseSymNodesCount )
+    nodeLayer->setExpanded( false );
 }
 
 QModelIndex QgsLayerTreeModel::currentIndex() const
@@ -732,6 +739,13 @@ void QgsLayerTreeModel::connectToLayer( QgsLayerTreeLayer* nodeLayer )
   if ( testFlag( ShowSymbology ) )
   {
     addSymbologyToLayer( nodeLayer );
+
+    // automatic collapse of symbology nodes - useful if a layer has many symbology nodes
+    if ( !mRootNode->customProperty( "loading" ).toBool() )
+    {
+      if ( mAutoCollapseSymNodesCount != -1 && rowCount( node2index( nodeLayer ) )  >= mAutoCollapseSymNodesCount )
+        nodeLayer->setExpanded( false );
+    }
   }
 
   QgsMapLayer* layer = nodeLayer->layer();

src/gui/layertree/qgslayertreemodel.h

@@ -139,6 +139,11 @@ class GUI_EXPORT QgsLayerTreeModel : public QAbstractItemModel
     //! Get font for a particular type of layer tree node. nodeType should come from QgsLayerTreeNode::NodeType enumeration
     QFont layerTreeNodeFont( int nodeType ) const;
 
+    //! Set at what number of symbology nodes the layer node should be collapsed. Setting -1 disables the auto-collapse (default).
+    void setAutoCollapseSymbologyNodes( int nodeCount ) { mAutoCollapseSymNodesCount = nodeCount; }
+    //! Return at what number of symbology nodes the layer node should be collapsed. -1 means no auto-collapse (default).
+    int autoCollapseSymbologyNodes() const { return mAutoCollapseSymNodesCount; }
+
   signals:
 
   protected slots:
@@ -180,6 +185,8 @@ class GUI_EXPORT QgsLayerTreeModel : public QAbstractItemModel
     QMap<QgsLayerTreeLayer*, QList<QgsLayerTreeModelSymbologyNode*> > mSymbologyNodes;
     //! Current index - will be underlined
     QPersistentModelIndex mCurrentIndex;
+    //! Minimal number of nodes when symbology should be automatically collapsed. -1 = disabled
+    int mAutoCollapseSymNodesCount;
 
     QFont mFontLayer;
     QFont mFontGroup;