Fix updating gui after undoing layout settings change

nyalldawson · nyalldawson · commit 94b63d17b726 · 2017-12-17T14:14:31.000+10:00
diff --git a/python/core/layout/qgslayout.sip b/python/core/layout/qgslayout.sip
@@ -541,6 +541,13 @@ Updates the scene bounds of the layout.
 
   signals:
 
+    void changed();
+%Docstring
+ Is emitted when properties of the layout change. This signal is only
+ emitted for settings directly managed by the layout, and is not emitted
+ when child items change.
+%End
+
     void variablesChanged();
 %Docstring
 Emitted whenever the expression variables stored in the layout have been changed.
diff --git a/src/app/layout/qgslayoutpropertieswidget.cpp b/src/app/layout/qgslayoutpropertieswidget.cpp
@@ -74,7 +74,14 @@ QgsLayoutPropertiesWidget::QgsLayoutPropertiesWidget( QWidget *parent, QgsLayout
   connect( mReferenceMapComboBox, &QgsLayoutItemComboBox::itemChanged, this, &QgsLayoutPropertiesWidget::referenceMapChanged );
 
   mReferenceMapComboBox->setCurrentLayout( mLayout );
-  mReferenceMapComboBox->setItem( mLayout->referenceMap() );
+
+  connect( mLayout, &QgsLayout::changed, this, &QgsLayoutPropertiesWidget::updateGui );
+  updateGui();
+}
+
+void QgsLayoutPropertiesWidget::updateGui()
+{
+  whileBlocking( mReferenceMapComboBox )->setItem( mLayout->referenceMap() );
 }
 
 void QgsLayoutPropertiesWidget::updateSnappingElements()
diff --git a/src/app/layout/qgslayoutpropertieswidget.h b/src/app/layout/qgslayoutpropertieswidget.h
@@ -30,6 +30,8 @@ class QgsLayoutPropertiesWidget: public QgsPanelWidget, private Ui::QgsLayoutWid
 
   private slots:
 
+    void updateGui();
+
     void gridResolutionChanged( double d );
     void gridResolutionUnitsChanged( QgsUnitTypes::LayoutUnit unit );
     void gridOffsetXChanged( double d );
diff --git a/src/core/layout/qgslayout.cpp b/src/core/layout/qgslayout.cpp
@@ -624,7 +624,7 @@ class QgsLayoutUndoCommand: public QgsAbstractLayoutUndoCommand
         return;
       }
 
-      mLayout->readXmlLayoutSettings( stateDoc.documentElement().firstChild().toElement(), stateDoc, QgsReadWriteContext() );
+      mLayout->readXmlLayoutSettings( stateDoc.documentElement(), stateDoc, QgsReadWriteContext() );
       mLayout->project()->setDirty( true );
     }
 
@@ -753,6 +753,7 @@ bool QgsLayout::readXmlLayoutSettings( const QDomElement &layoutElement, const Q
   setName( layoutElement.attribute( QStringLiteral( "name" ) ) );
   setUnits( QgsUnitTypes::decodeLayoutUnit( layoutElement.attribute( QStringLiteral( "units" ) ) ) );
   mWorldFileMapId = layoutElement.attribute( QStringLiteral( "worldFileMap" ) );
+  emit changed();
 
   return true;
 }
@@ -848,13 +849,17 @@ bool QgsLayout::readXml( const QDomElement &layoutElement, const QDomDocument &d
     return object->readXml( layoutElement, document, context );
   };
 
+  blockSignals( true ); // defer changed signal to end
   readXmlLayoutSettings( layoutElement, document, context );
+  blockSignals( false );
 
   restore( mPageCollection.get() );
   restore( &mSnapper );
   restore( &mGridSettings );
   addItemsFromXml( layoutElement, document, context );
 
+  emit changed();
+
   return true;
 }
 
diff --git a/src/core/layout/qgslayout.h b/src/core/layout/qgslayout.h
@@ -582,6 +582,13 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene, public QgsExpressionContext
 
   signals:
 
+    /**
+     * Is emitted when properties of the layout change. This signal is only
+     * emitted for settings directly managed by the layout, and is not emitted
+     * when child items change.
+     */
+    void changed();
+
     /**
      * Emitted whenever the expression variables stored in the layout have been changed.
      */
