Added a QgsRelation::polymorphicRelation() method

qgis · Jan 12, 2021 · 41e1e61 · 41e1e61
1 parent 81600fd
commit 41e1e61
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Showing 3 changed files with 25 additions and 5 deletions.
diff --git a/python/core/auto_generated/qgsrelation.sip.in b/python/core/auto_generated/qgsrelation.sip.in
@@ -326,6 +326,13 @@ Sets the parent polymorphic relation id.
 %Docstring
 Returns the parent polymorphic relation id. If the relation is a normal relation, a null string is returned.
 
+.. versionadded:: 3.18
+%End
+
+    QgsPolymorphicRelation polymorphicRelation() const;
+%Docstring
+Returns the parent polymorphic relation. If the relation is a normal relation, an invalid polymorphic relation is returned.
+
 .. versionadded:: 3.18
 %End
 

diff --git a/src/core/qgsrelation.cpp b/src/core/qgsrelation.cpp
@@ -206,11 +206,10 @@ QString QgsRelation::getRelatedFeaturesFilter( const QgsFeature &feature ) const
 
   if ( ! d->mPolymorphicRelationId.isEmpty() )
   {
-    QgsPolymorphicRelation polymorphicRelation = mContext.project()->relationManager()->polymorphicRelation( d->mPolymorphicRelationId );
-
-    if ( polymorphicRelation.isValid() )
+    QgsPolymorphicRelation polyRel = polymorphicRelation();
+    if ( polyRel.isValid() )
     {
-      conditions << QgsExpression::createFieldEqualityExpression( polymorphicRelation.referencedLayerField(), polymorphicRelation.layerRepresentation( referencedLayer() ) );
+      conditions << QgsExpression::createFieldEqualityExpression( polyRel.referencedLayerField(), polyRel.layerRepresentation( referencedLayer() ) );
     }
     else
     {
@@ -429,3 +428,10 @@ QString QgsRelation::polymorphicRelationId() const
   return d->mPolymorphicRelationId;
 }
 
+QgsPolymorphicRelation QgsRelation::polymorphicRelation() const
+{
+  if ( ! mContext.project() || ! mContext.project()->relationManager() )
+    return QgsPolymorphicRelation();
+
+  return mContext.project()->relationManager()->polymorphicRelation( d->mPolymorphicRelationId );
+}
diff --git a/src/core/qgsrelation.h b/src/core/qgsrelation.h
@@ -33,7 +33,7 @@ class QgsFeatureRequest;
 class QgsAttributes;
 class QgsVectorLayer;
 class QgsRelationPrivate;
-class QgsExpressionContext;
+class QgsPolymorphicRelation;
 
 /**
  * \ingroup core
@@ -49,6 +49,7 @@ class CORE_EXPORT QgsRelation
     Q_PROPERTY( QString name READ name WRITE setName )
     Q_PROPERTY( bool isValid READ isValid )
     Q_PROPERTY( QString polymorphicRelationId READ polymorphicRelationId WRITE setPolymorphicRelationId )
+    Q_PROPERTY( QgsPolymorphicRelation polymorphicRelation READ polymorphicRelation )
 
   public:
 
@@ -395,6 +396,12 @@ class CORE_EXPORT QgsRelation
      */
     QString polymorphicRelationId() const;
 
+    /**
+     * Returns the parent polymorphic relation. If the relation is a normal relation, an invalid polymorphic relation is returned.
+     * \since QGIS 3.18
+     */
+    QgsPolymorphicRelation polymorphicRelation() const;
+
   private:
 
     mutable QExplicitlySharedDataPointer<QgsRelationPrivate> d;