Introduce a FeaturesProxyModel to conditionally sort features list an…

…d value relations

MMFeaturesListPage is sorted according to the layer's QgsAttributeTableConfig
MMFormValueRelationEditor is sorted by value when the widget has the OrderByValue config set

app/CMakeLists.txt

@@ -52,6 +52,7 @@ set(MM_SRCS
     compass.cpp
     featurelayerpair.cpp
     featuresmodel.cpp
+    featuresproxymodel.cpp
     fieldsmodel.cpp
     guidelinecontroller.cpp
     identifykit.cpp
@@ -135,6 +136,7 @@ set(MM_HDRS
     enumhelper.h
     featurelayerpair.h
     featuresmodel.h
+    featuresproxymodel.h
     fieldsmodel.h
     guidelinecontroller.h
     identifykit.h

app/featuresmodel.cpp

@@ -141,6 +141,7 @@ QVariant FeaturesModel::data( const QModelIndex &index, int role ) const
     case LayerName: return pair.layer() ? pair.layer()->name() : QString();
     case LayerIcon: return pair.layer() ? InputUtils::loadIconFromLayer( pair.layer() ) : QString();
     case Qt::DisplayRole: return featureTitle( pair );
+    case SortValue: return sortValue( pair );
   }
 
   return QVariant();
@@ -171,6 +172,15 @@ QVariant FeaturesModel::featureTitle( const FeatureLayerPair &featurePair ) cons
   return title;
 }
 
+QVariant FeaturesModel::sortValue( const FeatureLayerPair &featurePair ) const
+{
+  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( featurePair.layer() ) );
+  context.setFeature( featurePair.feature() );
+  QgsExpression expr( mSortExpression );
+  QVariant result = expr.evaluate( &context );
+  return result;
+}
+
 QString FeaturesModel::searchResultPair( const FeatureLayerPair &pair ) const
 {
   if ( mSearchExpression.isEmpty() )
@@ -274,6 +284,7 @@ QHash<int, QByteArray> FeaturesModel::roleNames() const
   roleNames[SearchResult] = QStringLiteral( "SearchResult" ).toLatin1();
   roleNames[LayerName] = QStringLiteral( "LayerName" ).toLatin1();
   roleNames[LayerIcon] = QStringLiteral( "LayerIcon" ).toLatin1();
+  roleNames[SortValue] = QStringLiteral( "SortValue" ).toLatin1();
   return roleNames;
 }
 
@@ -359,10 +370,27 @@ void FeaturesModel::setLayer( QgsVectorLayer *newLayer )
     }
 
     emit layerFeaturesCountChanged( layerFeaturesCount() );
+    setupSorting();
   }
 }
 
 QgsVectorLayer *FeaturesModel::layer() const
 {
   return mLayer;
 }
+
+void FeaturesModel::setupSorting()
+{
+  mSortExpression = mLayer ? mLayer->attributeTableConfig().sortExpression() : QString();
+  mSortOrder = mLayer ? mLayer->attributeTableConfig().sortOrder() : Qt::AscendingOrder;
+}
+
+bool FeaturesModel::sortingEnabled() const
+{
+  return !mSortExpression.isEmpty();
+}
+
+Qt::SortOrder FeaturesModel::sortOrder() const
+{
+  return mSortOrder;
+}

app/featuresmodel.h

@@ -64,6 +64,7 @@ class FeaturesModel : public QAbstractListModel
       SearchResult, // pair of attribute and its value by which the feature was found, empty if search expression is empty
       LayerName,
       LayerIcon,
+      SortValue,
     };
     Q_ENUM( ModelRoles );
 
@@ -117,6 +118,12 @@ class FeaturesModel : public QAbstractListModel
 
     int layerFeaturesCount() const;
 
+    //! Returns true if there is a sort expression set for the model
+    bool sortingEnabled() const;
+
+    //! Returns the order in witch the model should be sorted
+    Qt::SortOrder sortOrder() const;
+
   signals:
 
     void featuresLimitChanged( int featuresLimit );
@@ -139,6 +146,12 @@ class FeaturesModel : public QAbstractListModel
 
     virtual QVariant featureTitle( const FeatureLayerPair &featurePair ) const;
 
+    //! Populates the sort expression and sort order for the model
+    virtual void setupSorting();
+
+    QString mSortExpression;
+    Qt::SortOrder mSortOrder = Qt::AscendingOrder;
+
   private slots:
     void onFutureFinished();
 
@@ -151,6 +164,9 @@ class FeaturesModel : public QAbstractListModel
     //! Returns found attribute and its value from search expression for feature
     QString searchResultPair( const FeatureLayerPair &feat ) const;
 
+    //! Evaluates the sort expression and returns the value used for this feature when sorting the model
+    QVariant sortValue( const FeatureLayerPair &featurePair ) const;
+
     const int FEATURES_LIMIT = 10000; //!< Number of maximum features loaded from layer
 
     FeatureLayerPairs mFeatures;

app/featuresproxymodel.cpp

@@ -0,0 +1,41 @@
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "featuresproxymodel.h"
+
+FeaturesProxyModel::FeaturesProxyModel( QObject *parent ) : QSortFilterProxyModel( parent )
+{
+}
+
+void FeaturesProxyModel::initialize()
+{
+  setSourceModel( mModel );
+
+  // don't sort if there is no sort expression for the layer
+  if ( mModel->sortingEnabled() )
+  {
+    setSortRole( FeaturesModel::SortValue );
+    setSortCaseSensitivity( Qt::CaseInsensitive );
+    sort( 0, mModel->sortOrder() );
+  }
+}
+
+FeaturesModel *FeaturesProxyModel::featuresSourceModel() const
+{
+  return mModel;
+}
+
+void FeaturesProxyModel::setFeaturesSourceModel( FeaturesModel *sourceModel )
+{
+  if ( mModel == sourceModel )
+    return;
+
+  mModel = sourceModel;
+  QObject::connect( mModel, &FeaturesModel::fetchingResultsChanged, this, [ = ]( bool pending ) { if ( !pending ) initialize(); } );
+}

app/featuresproxymodel.h

@@ -0,0 +1,51 @@
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef FEATURESPROXYMODEL_H
+#define FEATURESPROXYMODEL_H
+
+#include <QObject>
+#include <QSortFilterProxyModel>
+
+#include "inputconfig.h"
+#include "featuresmodel.h"
+
+/**
+ * \brief The FeaturesProxyModel class used as a proxy sort model for the \see FeaturesModel class.
+ *
+ * FeaturesProxyModel is a QML type with required property of FeatureSourceModel. Without source model, this model does nothing (is not initialized).
+ * After setting source model, this model starts sorting and allows filtering (search) from view.
+ */
+class FeaturesProxyModel : public QSortFilterProxyModel
+{
+    Q_OBJECT
+
+    Q_PROPERTY( FeaturesModel *featuresSourceModel READ featuresSourceModel WRITE setFeaturesSourceModel )
+
+  public:
+    explicit FeaturesProxyModel( QObject *parent = nullptr );
+    ~FeaturesProxyModel() override {};
+
+    FeaturesModel *featuresSourceModel() const;
+
+  public slots:
+    void setFeaturesSourceModel( FeaturesModel *sourceModel );
+
+  private:
+    void initialize();
+
+    FeaturesModel *mModel = nullptr; // not owned by this, needs to be set in order to proxy model to work
+
+    Qt::SortOrder mSortOrder = Qt::SortOrder::AscendingOrder;
+    QString mSortExpression;
+
+    friend class TestModels;
+};
+
+#endif // FEATURESPROXYMODEL_H

app/main.cpp

@@ -91,6 +91,7 @@
 #include "position/positionkit.h"
 #include "scalebarkit.h"
 #include "featuresmodel.h"
+#include "featuresproxymodel.h"
 #include "relationfeaturesmodel.h"
 #include "relationreferencefeaturesmodel.h"
 #include "fieldvalidator.h"
@@ -326,6 +327,7 @@ void initDeclarative()
   qmlRegisterType< MapThemesModel >( "mm", 1, 0, "MapThemesModel" );
   qmlRegisterType< GuidelineController >( "mm", 1, 0, "GuidelineController" );
   qmlRegisterType< FeaturesModel >( "mm", 1, 0, "FeaturesModel" );
+  qmlRegisterType< FeaturesProxyModel >( "mm", 1, 0, "FeaturesProxyModel" );
   qmlRegisterType< RelationFeaturesModel >( "mm", 1, 0, "RelationFeaturesModel" );
   qmlRegisterType< ValueRelationFeaturesModel >( "mm", 1, 0, "ValueRelationFeaturesModel" );
   qmlRegisterType< RelationReferenceFeaturesModel >( "mm", 1, 0, "RelationReferenceFeaturesModel" );

app/qml/form/editors/MMFormValueRelationEditor.qml

@@ -76,11 +76,15 @@ MMFormComboboxBaseEditor {
       valueRole: "FeatureId"
       textRole: "FeatureTitle"
 
-      list.model: MM.ValueRelationFeaturesModel {
-        id: vrDropdownModel
+      list.model: MM.FeaturesProxyModel {
+        id: vrDropdownProxyModel
 
-        config: root._fieldConfig
-        pair: root._fieldFeatureLayerPair
+        featuresSourceModel: MM.ValueRelationFeaturesModel {
+          id: vrDropdownModel
+
+          config: root._fieldConfig
+          pair: root._fieldFeatureLayerPair
+        }
       }
 
       onSearchTextChanged: ( searchText ) => vrDropdownModel.searchExpression = searchText

app/qml/layers/MMFeaturesListPage.qml

@@ -55,10 +55,14 @@ MMComponents.MMPage {
         topMargin: __style.spacing20
       }
 
-      model: MM.FeaturesModel {
-        id: featuresModel
+      model: MM.FeaturesProxyModel {
+        id: featuresProxyModel
 
-        layer: root.selectedLayer
+        featuresSourceModel: MM.FeaturesModel {
+          id: featuresModel
+
+          layer: root.selectedLayer
+        }
       }
 
       clip: true

app/relationfeaturesmodel.cpp

@@ -157,3 +157,8 @@ void RelationFeaturesModel::setHomePath( const QString &homePath )
     emit homePathChanged();
   }
 }
+
+void RelationFeaturesModel::setupSorting()
+{
+  mSortExpression.clear();
+}

app/relationfeaturesmodel.h

@@ -50,6 +50,7 @@ class RelationFeaturesModel : public FeaturesModel
 
     void setup() override;
     void setupFeatureRequest( QgsFeatureRequest &request ) override;
+    void setupSorting() override;
 
     void setParentFeatureLayerPair( FeatureLayerPair pair );
     void setRelation( QgsRelation relation );

app/relationreferencefeaturesmodel.cpp

@@ -121,3 +121,8 @@ void RelationReferenceFeaturesModel::setProject( QgsProject *project )
     setup();
   }
 }
+
+void RelationReferenceFeaturesModel::setupSorting()
+{
+  mSortExpression.clear();
+}

app/relationreferencefeaturesmodel.h

@@ -53,6 +53,8 @@ class RelationReferenceFeaturesModel : public FeaturesModel
     //! Reads config and with project instance queries all features from parent layer. Emits populated signal after loading features.
     void setup() override;
 
+    void setupSorting() override;
+
   signals:
     void configChanged( QVariantMap config );
     void projectChanged( QgsProject *project );

app/valuerelationfeaturesmodel.cpp

@@ -207,3 +207,9 @@ void ValueRelationFeaturesModel::setConfig( const QVariantMap &newConfig )
 
   setup();
 }
+
+void ValueRelationFeaturesModel::setupSorting()
+{
+  const bool orderByValue = mConfig.value( QStringLiteral( "OrderByValue" ) ).toBool();
+  mSortExpression = orderByValue ? mTitleField : QString();
+}

app/valuerelationfeaturesmodel.h

@@ -37,6 +37,7 @@ class ValueRelationFeaturesModel : public FeaturesModel
     void reset() override;
     void setupFeatureRequest( QgsFeatureRequest &request ) override;
     QVariant featureTitle( const FeatureLayerPair &pair ) const override;
+    void setupSorting() override;
 
     Q_INVOKABLE QVariant convertToKey( const QVariant &id );
     Q_INVOKABLE QVariant convertToQgisType( const QVariantList &featureIds ); // feature id -> key