Allow "order features by value" for relation reference widget

src/gui/editorwidgets/qgsrelationreferenceconfigdlg.cpp

@@ -45,6 +45,11 @@ void QgsRelationReferenceConfigDlg::setConfig( const QMap<QString, QVariant>& co
     mCbxAllowNull->setChecked( config[ "AllowNULL" ].toBool() );
   }
 
+  if ( config.contains( "OrderByValue" ) )
+  {
+    mCbxOrderByValue->setChecked( config[ "OrderByValue" ].toBool() );
+  }
+
   if ( config.contains( "ShowForm" ) )
   {
     mCbxShowForm->setChecked( config[ "ShowForm" ].toBool() );
@@ -84,6 +89,7 @@ QgsEditorWidgetConfig QgsRelationReferenceConfigDlg::config()
 {
   QgsEditorWidgetConfig myConfig;
   myConfig.insert( "AllowNULL", mCbxAllowNull->isChecked() );
+  myConfig.insert( "OrderByValue", mCbxOrderByValue->isChecked() );
   myConfig.insert( "ShowForm", mCbxShowForm->isChecked() );
   myConfig.insert( "MapIdentification", mCbxMapIdentification->isEnabled() && mCbxMapIdentification->isChecked() );
   myConfig.insert( "ReadOnly", mCbxReadOnly->isChecked() );

src/gui/editorwidgets/qgsrelationreferencefactory.cpp

@@ -42,6 +42,7 @@ QgsEditorWidgetConfig QgsRelationReferenceFactory::readConfig( const QDomElement
   QMap<QString, QVariant> cfg;
 
   cfg.insert( "AllowNULL", configElement.attribute( "AllowNULL" ) == "1" );
+  cfg.insert( "OrderByValue", configElement.attribute( "OrderByValue" ) == "1" );
   cfg.insert( "ShowForm", configElement.attribute( "ShowForm" ) == "1" );
   cfg.insert( "Relation", configElement.attribute( "Relation" ) );
   cfg.insert( "MapIdentification", configElement.attribute( "MapIdentification" ) == "1" );
@@ -57,6 +58,7 @@ void QgsRelationReferenceFactory::writeConfig( const QgsEditorWidgetConfig& conf
   Q_UNUSED( fieldIdx );
 
   configElement.setAttribute( "AllowNULL", config["AllowNULL"].toBool() );
+  configElement.setAttribute( "OrderByValue", config["OrderByValue"].toBool() );
   configElement.setAttribute( "ShowForm", config["ShowForm"].toBool() );
   configElement.setAttribute( "Relation", config["Relation"].toString() );
   configElement.setAttribute( "MapIdentification", config["MapIdentification"].toBool() );

src/gui/editorwidgets/qgsrelationreferencewidget.cpp

@@ -33,6 +33,24 @@
 #include "qgsrelationreferenceconfigdlg.h"
 #include "qgsvectorlayer.h"
 
+bool orderByLessThan( const QgsRelationReferenceWidget::ValueRelationItem& p1
+                      , const QgsRelationReferenceWidget::ValueRelationItem& p2 )
+{
+  switch ( p1.first.type() )
+  {
+    case QVariant::String:
+      return p1.first.toString() < p2.first.toString();
+      break;
+
+    case QVariant::Double:
+      return p1.first.toDouble() < p2.first.toDouble();
+      break;
+
+    default:
+      return p1.first.toInt() < p2.first.toInt();
+      break;
+  }
+}
 
 QgsRelationReferenceWidget::QgsRelationReferenceWidget( QWidget* parent )
     : QWidget( parent )
@@ -360,6 +378,11 @@ void QgsRelationReferenceWidget::setAllowMapIdentification( bool allowMapIdentif
   mAllowMapIdentification = allowMapIdentification;
 }
 
+void QgsRelationReferenceWidget::setOrderByValue( bool orderByValue )
+{
+  mOrderByValue = orderByValue;
+}
+
 void QgsRelationReferenceWidget::setOpenFormButtonVisible( bool openFormButtonVisible )
 {
   mOpenFormButton->setVisible( openFormButtonVisible );
@@ -398,15 +421,43 @@ void QgsRelationReferenceWidget::init()
     exp.prepare( mReferencedLayer->pendingFields() );
 
     QgsFeature f;
-    while ( fit.nextFeature( f ) )
+    if ( mOrderByValue )
+    {
+      ValueRelationCache cache;
+
+      QgsFeatureId currentSelection;
+
+      while ( fit.nextFeature( f ) )
+      {
+        QVariant val = exp.evaluate( &f );
+        cache.append( qMakePair( val, f.id() ) );
+        mFidFkMap.insert( f.id(), f.attribute( mFkeyFieldIdx ) );
+        if ( f.attribute( mFkeyFieldIdx ) == mForeignKey )
+          currentSelection = f.id();
+      }
+
+      qSort( cache.begin(), cache.end(), orderByLessThan );
+
+      Q_FOREACH( const ValueRelationItem& item, cache )
+      {
+        mComboBox->addItem( item.first.toString(), item.second );
+
+        if ( currentSelection == item.second )
+          mComboBox->setCurrentIndex( mComboBox->count() - 1 );
+      }
+    }
+    else
     {
-      QString txt = exp.evaluate( &f ).toString();
-      mComboBox->addItem( txt, f.id() );
+      while ( fit.nextFeature( f ) )
+      {
+        QString txt = exp.evaluate( &f ).toString();
+        mComboBox->addItem( txt, f.id() );
 
-      if ( f.attribute( mFkeyFieldIdx ) == mForeignKey )
-        mComboBox->setCurrentIndex( mComboBox->count() - 1 );
+        if ( f.attribute( mFkeyFieldIdx ) == mForeignKey )
+          mComboBox->setCurrentIndex( mComboBox->count() - 1 );
 
-      mFidFkMap.insert( f.id(), f.attribute( mFkeyFieldIdx ) );
+        mFidFkMap.insert( f.id(), f.attribute( mFkeyFieldIdx ) );
+      }
     }
 
     // Only connect after iterating, to have only one iterator on the referenced table at once

src/gui/editorwidgets/qgsrelationreferencewidget.h

@@ -36,6 +36,9 @@ class GUI_EXPORT QgsRelationReferenceWidget : public QWidget
     Q_PROPERTY( bool openFormButtonVisible READ openFormButtonVisible WRITE setOpenFormButtonVisible )
 
   public:
+    typedef QPair < QVariant, QgsFeatureId > ValueRelationItem;
+    typedef QVector < ValueRelationItem > ValueRelationCache;
+
     enum CanvasExtent
     {
       Fixed,
@@ -71,6 +74,11 @@ class GUI_EXPORT QgsRelationReferenceWidget : public QWidget
     bool allowMapIdentification() {return mAllowMapIdentification;}
     void setAllowMapIdentification( bool allowMapIdentification );
 
+    //! If the widget will order the combobox entries by value
+    bool orderByValue() { return mOrderByValue; }
+    //! Set if the widget will order the combobox entries by value
+    void setOrderByValue( bool orderByValue );
+
     //! determines the open form button is visible in the widget
     bool openFormButtonVisible() {return mOpenFormButtonVisible;}
     void setOpenFormButtonVisible( bool openFormButtonVisible );
@@ -133,6 +141,7 @@ class GUI_EXPORT QgsRelationReferenceWidget : public QWidget
     bool mEmbedForm;
     bool mReadOnlySelector;
     bool mAllowMapIdentification;
+    bool mOrderByValue;
     bool mOpenFormButtonVisible;
 
     // UI

src/gui/editorwidgets/qgsrelationreferencewidgetwrapper.cpp

@@ -48,10 +48,12 @@ void QgsRelationReferenceWidgetWrapper::initWidget( QWidget* editor )
   bool showForm = config( "ShowForm", true ).toBool();
   bool mapIdent = config( "MapIdentification", false ).toBool();
   bool readOnlyWidget = config( "ReadOnly", false ).toBool();
+  bool orderByValue = config( "OrderByValue", false ).toBool();
 
   mWidget->setEmbedForm( showForm );
   mWidget->setReadOnlySelector( readOnlyWidget );
   mWidget->setAllowMapIdentification( mapIdent );
+  mWidget->setOrderByValue( orderByValue );
 
   QgsRelation relation = QgsProject::instance()->relationManager()->relation( config( "Relation" ).toString() );
 

src/ui/editorwidgets/qgsrelationreferenceconfigdlgbase.ui

@@ -44,27 +44,34 @@
      </property>
     </widget>
    </item>
-   <item row="7" column="0" colspan="2">
+   <item row="8" column="0" colspan="2">
     <widget class="QCheckBox" name="mCbxShowForm">
      <property name="text">
       <string>Show embedded form</string>
      </property>
     </widget>
    </item>
-   <item row="8" column="0" colspan="2">
+   <item row="9" column="0" colspan="2">
     <widget class="QCheckBox" name="mCbxMapIdentification">
      <property name="text">
       <string>On map identification (for geometric layers only)</string>
      </property>
     </widget>
    </item>
-   <item row="9" column="0" colspan="2">
+   <item row="10" column="0" colspan="2">
     <widget class="QCheckBox" name="mCbxReadOnly">
      <property name="text">
       <string>Use a read-only line edit instead of a combobox</string>
      </property>
     </widget>
    </item>
+   <item row="7" column="0" colspan="2">
+    <widget class="QCheckBox" name="mCbxOrderByValue">
+     <property name="text">
+      <string>Order by value</string>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
  <customwidgets>