Save edit widgets also to QML style information.

Fix #11123
Fix #10752

src/core/qgsvectorlayer.cpp

@@ -1485,7 +1485,8 @@ bool QgsVectorLayer::writeXml( QDomNode & layer_node,
 
 bool QgsVectorLayer::readSymbology( const QDomNode& node, QString& errorMessage )
 {
-  Q_UNUSED( errorMessage );
+  emit readCustomSymbology( node.toElement(), errorMessage );
+
   if ( hasGeometryType() )
   {
     // try renderer v2 first
@@ -1644,7 +1645,6 @@ bool QgsVectorLayer::readSymbology( const QDomNode& node, QString& errorMessage
   if ( !aliasesNode.isNull() )
   {
     QDomElement aliasElem;
-    QString name;
 
     QDomNodeList aliasNodeList = aliasesNode.toElement().elementsByTagName( "alias" );
     for ( int i = 0; i < aliasNodeList.size(); ++i )
@@ -1767,9 +1767,10 @@ QgsAttributeEditorElement* QgsVectorLayer::attributeEditorElementFromDomElement(
 
 bool QgsVectorLayer::writeSymbology( QDomNode& node, QDomDocument& doc, QString& errorMessage ) const
 {
-  Q_UNUSED( errorMessage );
   QDomElement mapLayerNode = node.toElement();
 
+  emit writeCustomSymbology( mapLayerNode, doc, errorMessage );
+
   if ( hasGeometryType() )
   {
     QDomElement rendererElement = mRendererV2->save( doc );
@@ -2822,8 +2823,10 @@ void QgsVectorLayer::uniqueValues( int index, QList<QVariant> &uniqueValues, int
     if ( mEditBuffer )
     {
       QSet<QString> vals;
-      Q_FOREACH ( const QVariant& v, uniqueValues )
+      Q_FOREACH( const QVariant& v, uniqueValues )
+      {
         vals << v.toString();
+      }
 
       QMapIterator< QgsFeatureId, QgsAttributeMap > it( mEditBuffer->changedAttributeValues() );
       while ( it.hasNext() && ( limit < 0 || uniqueValues.count() < limit ) )
@@ -3546,13 +3549,13 @@ void QgsVectorLayer::invalidateSymbolCountedFlag()
 
 void QgsVectorLayer::onRelationsLoaded()
 {
-  Q_FOREACH ( QgsAttributeEditorElement* elem, mAttributeEditorElements )
+  Q_FOREACH( QgsAttributeEditorElement* elem, mAttributeEditorElements )
   {
     if ( elem->type() == QgsAttributeEditorElement::AeTypeContainer )
     {
       QgsAttributeEditorContainer* cont = dynamic_cast< QgsAttributeEditorContainer* >( elem );
       QList<QgsAttributeEditorElement*> relations = cont->findElements( QgsAttributeEditorElement::AeTypeRelation );
-      Q_FOREACH ( QgsAttributeEditorElement* relElem, relations )
+      Q_FOREACH( QgsAttributeEditorElement* relElem, relations )
       {
         QgsAttributeEditorRelation* rel = dynamic_cast< QgsAttributeEditorRelation* >( relElem );
         rel->init( QgsProject::instance()->relationManager() );
@@ -3608,7 +3611,7 @@ QDomElement QgsAttributeEditorContainer::toDomElement( QDomDocument& doc ) const
   QDomElement elem = doc.createElement( "attributeEditorContainer" );
   elem.setAttribute( "name", mName );
 
-  Q_FOREACH ( QgsAttributeEditorElement* child, mChildren )
+  Q_FOREACH( QgsAttributeEditorElement* child, mChildren )
   {
     elem.appendChild( child->toDomElement( doc ) );
   }
@@ -3624,7 +3627,7 @@ QList<QgsAttributeEditorElement*> QgsAttributeEditorContainer::findElements( Qgs
 {
   QList<QgsAttributeEditorElement*> results;
 
-  Q_FOREACH ( QgsAttributeEditorElement* elem, mChildren )
+  Q_FOREACH( QgsAttributeEditorElement* elem, mChildren )
   {
     if ( elem->type() == type )
     {

src/core/qgsvectorlayer.h

@@ -1685,6 +1685,28 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
      */
     void editCommandDestroyed();
 
+    /**
+     * Signal emitted whenever the symbology (QML-file) for this layer is being read.
+     * If there is custom style information saved in the file, you can connect to this signal
+     * and update the layer style accordingly.
+     *
+     * @param element The XML layer style element.
+     *
+     * @param errorMessage Write error messages into this string.
+     */
+    void readCustomSymbology( const QDomElement& element, QString& errorMessage );
+
+    /**
+     * Signal emitted whenever the symbology (QML-file) for this layer is being written.
+     * If there is custom style information you want to save to the file, you can connect
+     * to this signal and update the element accordingly.
+     *
+     * @param element  The XML element where you can add additional style information to.
+     * @param doc      The XML document that you can use to create new XML nodes.
+     * @param errorMessage Write error messages into this string.
+     */
+    void writeCustomSymbology( QDomElement& element, QDomDocument& doc, QString& errorMessage ) const;
+
   private slots:
     void onRelationsLoaded();
     void onJoinedFieldsChanged();

src/gui/editorwidgets/core/qgseditorwidgetregistry.cpp

@@ -21,6 +21,7 @@
 #include "qgsmessagelog.h"
 #include "qgsproject.h"
 #include "qgsvectorlayer.h"
+#include "qgsmaplayerregistry.h"
 
 QgsEditorWidgetRegistry* QgsEditorWidgetRegistry::instance()
 {
@@ -32,6 +33,8 @@ QgsEditorWidgetRegistry::QgsEditorWidgetRegistry()
 {
   connect( QgsProject::instance(), SIGNAL( readMapLayer( QgsMapLayer*, const QDomElement& ) ), this, SLOT( readMapLayer( QgsMapLayer*, const QDomElement& ) ) );
   connect( QgsProject::instance(), SIGNAL( writeMapLayer( QgsMapLayer*, QDomElement&, QDomDocument& ) ), this, SLOT( writeMapLayer( QgsMapLayer*, QDomElement&, QDomDocument& ) ) );
+
+  connect( QgsMapLayerRegistry::instance(), SIGNAL( layerWasAdded( QgsMapLayer* ) ), this, SLOT( mapLayerAdded( QgsMapLayer* ) ) );
 }
 
 QgsEditorWidgetRegistry::~QgsEditorWidgetRegistry()
@@ -177,7 +180,7 @@ const QString QgsEditorWidgetRegistry::readLegacyConfig( QgsVectorLayer* vl, con
   Q_NOWARN_DEPRECATED_POP
 }
 
-void QgsEditorWidgetRegistry::writeMapLayer( QgsMapLayer* mapLayer, QDomElement& layerElem, QDomDocument& doc )
+void QgsEditorWidgetRegistry::writeMapLayer( QgsMapLayer* mapLayer, QDomElement& layerElem, QDomDocument& doc ) const
 {
   if ( mapLayer->type() != QgsMapLayer::VectorLayer )
   {
@@ -223,3 +226,34 @@ void QgsEditorWidgetRegistry::writeMapLayer( QgsMapLayer* mapLayer, QDomElement&
 
   layerElem.appendChild( editTypesNode );
 }
+
+void QgsEditorWidgetRegistry::mapLayerAdded( QgsMapLayer* mapLayer )
+{
+  QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( mapLayer );
+
+  if ( vl )
+  {
+    connect( vl, SIGNAL( readCustomSymbology( const QDomElement&, QString& ) ), this, SLOT( readSymbology( const QDomElement&, QString& ) ) );
+    connect( vl, SIGNAL( writeCustomSymbology( QDomElement&, QDomDocument&, QString& ) ), this, SLOT( writeSymbology( QDomElement&, QDomDocument&, QString& ) ) );
+  }
+}
+
+void QgsEditorWidgetRegistry::readSymbology( const QDomElement& element, QString& errorMessage )
+{
+  Q_UNUSED( errorMessage )
+  QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( sender() );
+
+  Q_ASSERT( vl );
+
+  readMapLayer( vl, element );
+}
+
+void QgsEditorWidgetRegistry::writeSymbology( QDomElement& element, QDomDocument& doc, QString& errorMessage )
+{
+  Q_UNUSED( errorMessage )
+  QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( sender() );
+
+  Q_ASSERT( vl );
+
+  writeMapLayer( vl, element, doc );
+}

src/gui/editorwidgets/core/qgseditorwidgetregistry.h

@@ -136,7 +136,33 @@ class GUI_EXPORT QgsEditorWidgetRegistry : public QObject
      * @param layerElem  The XML element to which the config will be written
      * @param doc        The document from which to create elements
      */
-    void writeMapLayer( QgsMapLayer* mapLayer , QDomElement& layerElem, QDomDocument& doc );
+    void writeMapLayer( QgsMapLayer* mapLayer , QDomElement& layerElem, QDomDocument& doc ) const;
+
+    /**
+     * Will connect to appropriate signals from map layers to load and save style
+     *
+     * @param mapLayer The layer to connect
+     */
+    void mapLayerAdded( QgsMapLayer* mapLayer );
+
+    /**
+     * Loads layer symbology for the layer that emitted the signal
+     *
+     * @param element The XML element containing the style information
+     *
+     * @param errorMessage Errors will be written into this string (unused)
+     */
+    void readSymbology( const QDomElement& element, QString& errorMessage );
+
+    /**
+     * Saves layer symbology for the layer that emitted the signal
+     *
+     * @param element The XML element where the style information be written to
+     * @param doc     The XML document where the style information be written to
+     *
+     * @param errorMessage Errors will be written into this string (unused)
+     */
+    void writeSymbology( QDomElement& element, QDomDocument& doc, QString& errorMessage );
 
   private:
     QMap<QString, QgsEditorWidgetFactory*> mWidgetFactories;