Add a changed signal to QgsRelationManager

python/core/qgsrelationmanager.sip

@@ -22,4 +22,10 @@ class QgsRelationManager : QObject
 
   signals:
     void relationsLoaded();
+    
+    /**
+     * Emitted when relations are added or removed to the manager.
+     * @note added in QGIS 2.5
+     */
+    void changed();
 };

src/core/qgsrelationmanager.cpp

@@ -37,6 +37,7 @@ void QgsRelationManager::setRelations( const QList<QgsRelation>& relations )
   {
     addRelation( rel );
   }
+  emit changed();
 }
 
 const QMap<QString, QgsRelation>& QgsRelationManager::relations() const
@@ -52,16 +53,19 @@ void QgsRelationManager::addRelation( const QgsRelation& relation )
   mRelations.insert( relation.id(), relation );
 
   mProject->dirty( true );
+  emit changed();
 }
 
 void QgsRelationManager::removeRelation( const QString& name )
 {
   mRelations.remove( name );
+  emit changed();
 }
 
 void QgsRelationManager::removeRelation( const QgsRelation& relation )
 {
   mRelations.remove( relation.id() );
+  emit changed();
 }
 
 QgsRelation QgsRelationManager::relation( const QString& id ) const
@@ -72,6 +76,7 @@ QgsRelation QgsRelationManager::relation( const QString& id ) const
 void QgsRelationManager::clear()
 {
   mRelations.clear();
+  emit changed();
 }
 
 QList<QgsRelation> QgsRelationManager::referencingRelations( QgsVectorLayer* layer, int fieldIdx ) const
@@ -152,6 +157,7 @@ void QgsRelationManager::readProject( const QDomDocument & doc )
   }
 
   emit( relationsLoaded() );
+  emit changed();
 }
 
 void QgsRelationManager::writeProject( QDomDocument & doc )
@@ -175,7 +181,8 @@ void QgsRelationManager::writeProject( QDomDocument & doc )
 
 void QgsRelationManager::layersRemoved( const QStringList& layers )
 {
-  Q_FOREACH ( const QString& layer, layers )
+  bool relationsChanged = false;
+  Q_FOREACH( const QString& layer, layers )
   {
     QMapIterator<QString, QgsRelation> it( mRelations );
 
@@ -187,7 +194,12 @@ void QgsRelationManager::layersRemoved( const QStringList& layers )
            || it.value().referencingLayerId() == layer )
       {
         mRelations.remove( it.key() );
+        relationsChanged = true;
       }
     }
   }
+  if ( relationsChanged )
+  {
+    emit changed();
+  }
 }

src/core/qgsrelationmanager.h

@@ -107,6 +107,12 @@ class CORE_EXPORT QgsRelationManager : public QObject
   signals:
     void relationsLoaded();
 
+    /**
+     * Emitted when relations are added or removed to the manager.
+     * @note added in QGIS 2.5
+     */
+    void changed();
+
   private slots:
     void readProject( const QDomDocument &doc );
     void writeProject( QDomDocument &doc );