Digitize the geometry from the relation reference widget add button (#30905)

* [FEATURE] [needs-docs] Add the possibility to digitize the geometry
when creating a feature from the plus button on the relation reference widget

python/gui/auto_generated/editorwidgets/qgsrelationreferencewidget.sip.in

@@ -160,6 +160,13 @@ Determines if a button for adding new features should be shown.
 %Docstring
 Returns the current relation, which might be invalid
 
+.. versionadded:: 3.10
+%End
+
+    void setFormFeature( const QgsFeature &formFeature );
+%Docstring
+Set the current form feature (from the referencing layer)
+
 .. versionadded:: 3.10
 %End
 

python/gui/auto_generated/qgsattributeeditorcontext.sip.in

@@ -94,6 +94,32 @@ Returns the associated map canvas (e.g. to zoom to related features).
 .. seealso:: :py:func:`setMapCanvas`
 
 .. versionadded:: 3.2
+%End
+
+    void setCadDockWidget( QgsAdvancedDigitizingDockWidget *cadDockWidget );
+%Docstring
+Sets the associated CAD dock widget, ``cadDockWidget``, (e.g. to be used in map tools).
+
+.. note::
+
+   Unstable API. This method is unstable API and may be modified or removed at any time.
+
+.. seealso:: :py:func:`cadDockWidget`
+
+.. versionadded:: 3.10
+%End
+
+    QgsAdvancedDigitizingDockWidget *cadDockWidget() const;
+%Docstring
+Returns the associated CAD dock widget (e.g. to be used in map tools).
+
+.. note::
+
+   Unstable API. This method is unstable API and may be modified or removed at any time.
+
+.. seealso:: :py:func:`setCadDockWidget`
+
+.. versionadded:: 3.10
 %End
 
     void setVectorLayerTools( QgsVectorLayerTools *vlTools );
@@ -234,7 +260,6 @@ Returns given ``attributeFormMode`` as string
 
 };
 
-
 /************************************************************************
  * This file has been generated automatically from                      *
  *                                                                      *

python/gui/auto_generated/qgsmaptooldigitizefeature.sip.in

@@ -0,0 +1,89 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsmaptooldigitizefeature.h                                  *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+class QgsMapToolDigitizeFeature : QgsMapToolCapture
+{
+%Docstring
+This tool digitizes geometry of new point/line/polygon features on already existing vector layers
+Once the map tool is enabled, user can digitize the feature geometry.
+A signal will then be emitted.
+
+.. versionadded:: 3.10
+%End
+
+%TypeHeaderCode
+#include "qgsmaptooldigitizefeature.h"
+%End
+  public:
+
+    QgsMapToolDigitizeFeature( QgsMapCanvas *canvas, QgsAdvancedDigitizingDockWidget *cadDockWidget, CaptureMode mode = QgsMapToolCapture::CaptureNone );
+%Docstring
+QgsMapToolDigitizeFeature is a map tool to digitize a feature geometry
+
+:param canvas: the map canvas
+:param cadDockWidget: widget to setup advanced digitizing parameters
+:param mode: type of geometry to capture (point/line/polygon), QgsMapToolCapture.CaptureNone to autodetect geometry
+%End
+
+    virtual void cadCanvasReleaseEvent( QgsMapMouseEvent *e );
+
+
+    void setLayer( QgsMapLayer *vl );
+%Docstring
+Change the layer edited by the map tool
+
+:param vl: the layer to be edited by the map tool
+%End
+
+    virtual void activate();
+
+    virtual void deactivate();
+
+
+  signals:
+
+    void digitizingCompleted( const QgsFeature &feature );
+%Docstring
+Emitted whenever the digitizing has been successfully completed
+
+:param feature: the new digitized feature
+%End
+
+    void digitizingFinished( );
+%Docstring
+Emitted whenever the digitizing has been ended without digitizing
+any feature
+%End
+
+  protected:
+
+    bool checkGeometryType() const;
+%Docstring
+Check if CaptureMode matches layer type. Default is true.
+
+.. versionadded:: 3.0
+%End
+
+    void setCheckGeometryType( bool checkGeometryType );
+%Docstring
+Check if CaptureMode matches layer type. Default is true.
+
+.. versionadded:: 3.0
+%End
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsmaptooldigitizefeature.h                                  *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/gui/gui_auto.sip

@@ -155,6 +155,7 @@
 %Include auto_generated/qgsmaptooladvanceddigitizing.sip
 %Include auto_generated/qgsmaptoolcapture.sip
 %Include auto_generated/qgsmaptooledit.sip
+%Include auto_generated/qgsmaptooldigitizefeature.sip
 %Include auto_generated/qgsmaptoolemitpoint.sip
 %Include auto_generated/qgsmaptoolextent.sip
 %Include auto_generated/qgsmaptoolidentify.sip

src/app/CMakeLists.txt

@@ -82,7 +82,6 @@ SET(QGIS_APP_SRCS
   qgswelcomepage.cpp
 
   qgsmaptooladdfeature.cpp
-  qgsmaptooldigitizefeature.cpp
   qgsmaptooladdpart.cpp
   qgsmaptooladdring.cpp
   qgsmaptoolfillring.cpp
@@ -327,7 +326,6 @@ SET (QGIS_APP_MOC_HDRS
   qgswelcomepage.h
 
   qgsmaptooladdfeature.h
-  qgsmaptooldigitizefeature.h
   qgsmaptoolannotation.h
   qgsmaptoolcircularstringradius.h
   qgsmaptooladdpart.h

src/app/qgisapp.cpp

@@ -14672,7 +14672,8 @@ QgsFeature QgisApp::duplicateFeatureDigitized( QgsMapLayer *mlayer, const QgsFea
     return QgsFeature();
   }
 
-  QgsMapToolDigitizeFeature *digitizeFeature = new QgsMapToolDigitizeFeature( mMapCanvas, mlayer, QgsMapToolCapture::CaptureNone );
+  QgsMapToolDigitizeFeature *digitizeFeature = new QgsMapToolDigitizeFeature( mMapCanvas, mAdvancedDigitizingDockWidget, QgsMapToolCapture::CaptureNone );
+  digitizeFeature->setLayer( layer );
 
   mMapCanvas->setMapTool( digitizeFeature );
   mMapCanvas->window()->raise();

src/app/qgsattributetabledialog.cpp

@@ -158,6 +158,7 @@ QgsAttributeTableDialog::QgsAttributeTableDialog( QgsVectorLayer *layer, QgsAttr
 
   mEditorContext.setVectorLayerTools( QgisApp::instance()->vectorLayerTools() );
   mEditorContext.setMapCanvas( QgisApp::instance()->mapCanvas() );
+  mEditorContext.setCadDockWidget( QgisApp::instance()->cadDockWidget() );
 
   QgsFeatureRequest r;
   bool needsGeom = false;

src/app/qgsmaptooladdfeature.cpp

@@ -37,18 +37,21 @@
 #include <QSettings>
 
 QgsMapToolAddFeature::QgsMapToolAddFeature( QgsMapCanvas *canvas, CaptureMode mode )
-  : QgsMapToolDigitizeFeature( canvas, canvas->currentLayer(), mode )
+  : QgsMapToolDigitizeFeature( canvas, QgisApp::instance()->cadDockWidget(), mode )
   , mCheckGeometryType( true )
 {
+  setLayer( canvas->currentLayer() );
+
   mToolName = tr( "Add feature" );
   connect( QgisApp::instance(), &QgisApp::newProject, this, &QgsMapToolAddFeature::stopCapturing );
   connect( QgisApp::instance(), &QgisApp::projectRead, this, &QgsMapToolAddFeature::stopCapturing );
 }
 
-bool QgsMapToolAddFeature::addFeature( QgsVectorLayer *vlayer, QgsFeature *f, bool showModal )
+bool QgsMapToolAddFeature::addFeature( QgsVectorLayer *vlayer, const QgsFeature &f, bool showModal )
 {
+  QgsFeature feat( f );
   QgsExpressionContextScope *scope = QgsExpressionContextUtils::mapToolCaptureScope( snappingMatches() );
-  QgsFeatureAction *action = new QgsFeatureAction( tr( "add feature" ), *f, vlayer, QString(), -1, this );
+  QgsFeatureAction *action = new QgsFeatureAction( tr( "add feature" ), feat, vlayer, QString(), -1, this );
   QgsRubberBand *rb = takeRubberBand();
   connect( action, &QgsFeatureAction::addFeatureFinished, rb, &QgsRubberBand::deleteLater );
   bool res = action->addFeature( QgsAttributeMap(), showModal, scope );
@@ -57,10 +60,10 @@ bool QgsMapToolAddFeature::addFeature( QgsVectorLayer *vlayer, QgsFeature *f, bo
   return res;
 }
 
-void QgsMapToolAddFeature::digitized( QgsFeature &f )
+void QgsMapToolAddFeature::digitized( const QgsFeature &f )
 {
   QgsVectorLayer *vlayer = currentVectorLayer();
-  bool res = addFeature( vlayer, &f, false );
+  bool res = addFeature( vlayer, f, false );
 
   if ( res && ( mode() == CaptureLine || mode() == CapturePolygon ) )
   {

src/app/qgsmaptooladdfeature.h

@@ -14,6 +14,7 @@
  ***************************************************************************/
 
 #include "qgsmaptooldigitizefeature.h"
+#include "qgis_app.h"
 
 //! This tool adds new point/line/polygon features to already existing vector layers
 class APP_EXPORT QgsMapToolAddFeature : public QgsMapToolDigitizeFeature
@@ -23,12 +24,12 @@ class APP_EXPORT QgsMapToolAddFeature : public QgsMapToolDigitizeFeature
     //! \since QGIS 2.12
     QgsMapToolAddFeature( QgsMapCanvas *canvas, CaptureMode mode );
 
-    bool addFeature( QgsVectorLayer *vlayer, QgsFeature *f, bool showModal = true );
-
-    void digitized( QgsFeature &f ) override;
-
   private:
 
+    bool addFeature( QgsVectorLayer *vlayer, const QgsFeature &f, bool showModal = true );
+
+    void digitized( const QgsFeature &f ) override;
+
     /**
      * Check if CaptureMode matches layer type. Default is true.
      * \since QGIS 2.12 */

src/gui/CMakeLists.txt

@@ -234,6 +234,7 @@ SET(QGIS_GUI_SRCS
   qgsaggregatetoolbutton.cpp
   qgsalignmentcombobox.cpp
   qgsattributedialog.cpp
+  qgsattributeeditorcontext.cpp
   qgsattributeform.cpp
   qgsattributeformeditorwidget.cpp
   qgsattributeforminterface.cpp
@@ -337,6 +338,7 @@ SET(QGIS_GUI_SRCS
   qgsmaptooladvanceddigitizing.cpp
   qgsmaptoolcapture.cpp
   qgsmaptooledit.cpp
+  qgsmaptooldigitizefeature.cpp
   qgsmaptoolemitpoint.cpp
   qgsmaptoolextent.cpp
   qgsmaptoolidentify.cpp
@@ -522,6 +524,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsmaptooladvanceddigitizing.h
   qgsmaptoolcapture.h
   qgsmaptooledit.h
+  qgsmaptooldigitizefeature.h
   qgsmaptoolemitpoint.h
   qgsmaptoolextent.h
   qgsmaptoolidentify.h

src/gui/editorwidgets/qgsrelationreferencewidget.cpp

@@ -38,6 +38,7 @@
 #include "qgsvectorlayer.h"
 #include "qgsattributetablemodel.h"
 #include "qgsmaptoolidentifyfeature.h"
+#include "qgsmaptooldigitizefeature.h"
 #include "qgsfeatureiterator.h"
 #include "qgsfeaturelistcombobox.h"
 #include "qgsexpressioncontextutils.h"
@@ -169,7 +170,6 @@ QgsRelationReferenceWidget::~QgsRelationReferenceWidget()
 {
   deleteHighlight();
   unsetMapTool();
-  delete mMapTool;
 }
 
 void QgsRelationReferenceWidget::updateIndex()
@@ -254,7 +254,9 @@ void QgsRelationReferenceWidget::setRelation( const QgsRelation &relation, bool
 void QgsRelationReferenceWidget::setRelationEditable( bool editable )
 {
   if ( !editable )
+  {
     unsetMapTool();
+  }
 
   mFilterContainer->setEnabled( editable );
   mComboBox->setEnabled( editable );
@@ -452,9 +454,11 @@ void QgsRelationReferenceWidget::setEditorContext( const QgsAttributeEditorConte
   mCanvas = canvas;
   mMessageBar = messageBar;
 
-  delete mMapTool;
-  mMapTool = new QgsMapToolIdentifyFeature( mCanvas );
-  mMapTool->setButton( mMapIdentificationButton );
+  mMapToolIdentify.reset( new QgsMapToolIdentifyFeature( mCanvas ) );
+  mMapToolIdentify->setButton( mMapIdentificationButton );
+
+  mMapToolDigitize.reset( new QgsMapToolDigitizeFeature( mCanvas, context.cadDockWidget() ) );
+  mMapToolDigitize->setButton( mAddEntryButton );
 }
 
 void QgsRelationReferenceWidget::setEmbedForm( bool display )
@@ -717,17 +721,10 @@ void QgsRelationReferenceWidget::mapIdentification()
   if ( !mCanvas )
     return;
 
-  mMapTool->setLayer( mReferencedLayer );
-  mCanvas->setMapTool( mMapTool );
+  mMapToolIdentify->setLayer( mReferencedLayer );
+  setMapTool( mMapToolIdentify );
 
-  mWindowWidget = window();
-
-  mCanvas->window()->raise();
-  mCanvas->activateWindow();
-  mCanvas->setFocus();
-
-  connect( mMapTool, static_cast<void ( QgsMapToolIdentifyFeature::* )( const QgsFeature & )>( &QgsMapToolIdentifyFeature::featureIdentified ), this, &QgsRelationReferenceWidget::featureIdentified );
-  connect( mMapTool, &QgsMapTool::deactivated, this, &QgsRelationReferenceWidget::mapToolDeactivated );
+  connect( mMapToolIdentify, qgis::overload<const QgsFeature &>::of( &QgsMapToolIdentifyFeature::featureIdentified ), this, &QgsRelationReferenceWidget::featureIdentified );
 
   if ( mMessageBar )
   {
@@ -809,13 +806,44 @@ void QgsRelationReferenceWidget::featureIdentified( const QgsFeature &feature )
   unsetMapTool();
 }
 
+void QgsRelationReferenceWidget::setMapTool( QgsMapTool *mapTool )
+{
+  mCurrentMapTool = mapTool;
+  mCanvas->setMapTool( mapTool );
+
+  mWindowWidget = window();
+
+  mCanvas->window()->raise();
+  mCanvas->activateWindow();
+  mCanvas->setFocus();
+  connect( mapTool, &QgsMapTool::deactivated, this, &QgsRelationReferenceWidget::mapToolDeactivated );
+}
+
 void QgsRelationReferenceWidget::unsetMapTool()
 {
-  // deactivate map tool if activated
-  if ( mCanvas && mMapTool )
+  // deactivate map tools if activated
+  if ( mCurrentMapTool )
   {
     /* this will call mapToolDeactivated */
-    mCanvas->unsetMapTool( mMapTool );
+    mCanvas->unsetMapTool( mCurrentMapTool );
+
+    if ( mCurrentMapTool == mMapToolDigitize )
+    {
+      disconnect( mCanvas, &QgsMapCanvas::keyPressed, this, &QgsRelationReferenceWidget::onKeyPressed );
+      disconnect( mMapToolDigitize, &QgsMapToolDigitizeFeature::digitizingCompleted, this, &QgsRelationReferenceWidget::entryAdded );
+    }
+    else
+    {
+      disconnect( mMapToolIdentify, qgis::overload<const QgsFeature &>::of( &QgsMapToolIdentifyFeature::featureIdentified ), this, &QgsRelationReferenceWidget::featureIdentified );
+    }
+  }
+}
+
+void QgsRelationReferenceWidget::onKeyPressed( QKeyEvent *e )
+{
+  if ( e->key() == Qt::Key_Escape )
+  {
+    unsetMapTool();
   }
 }
 
@@ -940,7 +968,53 @@ void QgsRelationReferenceWidget::filterChanged()
 
 void QgsRelationReferenceWidget::addEntry()
 {
-  QgsFeature f( mReferencedLayer->fields() );
+  if ( !mReferencedLayer )
+    return;
+
+  const QgsVectorLayerTools *tools = mEditorContext.vectorLayerTools();
+  if ( !tools )
+    return;
+  if ( !mCanvas )
+    return;
+
+  // no geometry, skip the digitizing
+  if ( mReferencedLayer->geometryType() == QgsWkbTypes::UnknownGeometry || mReferencedLayer->geometryType() == QgsWkbTypes::NullGeometry )
+  {
+    QgsFeature f( mReferencedLayer->fields() );
+    entryAdded( f );
+    return;
+  }
+
+  mMapToolDigitize->setLayer( mReferencedLayer );
+  setMapTool( mMapToolDigitize );
+
+  connect( mMapToolDigitize, &QgsMapToolDigitizeFeature::digitizingCompleted, this, &QgsRelationReferenceWidget::entryAdded );
+  connect( mCanvas, &QgsMapCanvas::keyPressed, this, &QgsRelationReferenceWidget::onKeyPressed );
+
+  if ( mMessageBar )
+  {
+    QString title = tr( "Relation %1 for %2." ).arg( mRelation.name(), mReferencingLayer->name() );
+
+    QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( mReferencingLayer ) );
+    if ( mCanvas )
+      context.appendScope( QgsExpressionContextUtils::mapSettingsScope( mCanvas->mapSettings() ) );
+
+    QgsExpression exp( mReferencingLayer->displayExpression() );
+    context.setFeature( mFormFeature );
+    exp.prepare( &context );
+    QString displayString = exp.evaluate( &context ).toString();
+
+    QString msg = tr( "Link feature to %1 \"%2\" : Digitize the geometry for the new feature on layer %3. Press &lt;ESC&gt; to cancel." )
+                  .arg( mReferencingLayer->name(), displayString, mReferencedLayer->name() );
+    mMessageBarItem = QgsMessageBar::createMessage( title, msg, this );
+    mMessageBar->pushItem( mMessageBarItem );
+  }
+
+}
+
+void QgsRelationReferenceWidget::entryAdded( const QgsFeature &feat )
+{
+  QgsFeature f( feat );
   QgsAttributeMap attributes;
 
   // if custom text is in the combobox and the displayExpression is simply a field, use the current text for the new feature
@@ -954,7 +1028,7 @@ void QgsRelationReferenceWidget::addEntry()
     }
   }
 
-  if ( mEditorContext.vectorLayerTools()->addFeature( mReferencedLayer, attributes, QgsGeometry(), &f ) )
+  if ( mEditorContext.vectorLayerTools()->addFeature( mReferencedLayer, attributes, f.geometry(), &f ) )
   {
     QVariantList attrs;
     for ( const QString &fieldName : qgis::as_const( mReferencedFields ) )
@@ -964,6 +1038,8 @@ void QgsRelationReferenceWidget::addEntry()
 
     mAddEntryButton->setEnabled( false );
   }
+
+  unsetMapTool();
 }
 
 void QgsRelationReferenceWidget::updateAddEntryButton()
@@ -1009,3 +1085,8 @@ void QgsRelationReferenceWidget::emitForeignKeysChanged( const QVariantList &for
   Q_NOWARN_DEPRECATED_POP
   emit foreignKeysChanged( foreignKeys );
 }
+
+void QgsRelationReferenceWidget::setFormFeature( const QgsFeature &formFeature )
+{
+  mFormFeature = formFeature;
+}

src/gui/editorwidgets/qgsrelationreferencewidget.h

@@ -19,6 +19,7 @@
 #include "qgsattributeeditorcontext.h"
 #include "qgis_sip.h"
 #include "qgsfeature.h"
+#include "qobjectuniqueptr.h"
 
 #include <QComboBox>
 #include <QToolButton>
@@ -32,7 +33,9 @@ class QgsVectorLayerTools;
 class QgsMapCanvas;
 class QgsMessageBar;
 class QgsHighlight;
+class QgsMapTool;
 class QgsMapToolIdentifyFeature;
+class QgsMapToolDigitizeFeature;
 class QgsMessageBarItem;
 class QgsFeatureListComboBox;
 class QgsCollapsibleGroupBox;
@@ -181,6 +184,13 @@ class GUI_EXPORT QgsRelationReferenceWidget : public QWidget
      */
     QgsRelation relation() const;
 
+    /**
+     * Set the current form feature (from the referencing layer)
+     *
+     * \since QGIS 3.10
+     */
+    void setFormFeature( const QgsFeature &formFeature );
+
   public slots:
     //! open the form of the related feature in a new dialog
     void openForm();
@@ -215,11 +225,14 @@ class GUI_EXPORT QgsRelationReferenceWidget : public QWidget
     void deleteHighlight();
     void comboReferenceChanged( int index );
     void featureIdentified( const QgsFeature &feature );
+    void setMapTool( QgsMapTool *mapTool );
     void unsetMapTool();
     void mapToolDeactivated();
     void filterChanged();
     void addEntry();
     void updateAddEntryButton();
+    void entryAdded( const QgsFeature &f );
+    void onKeyPressed( QKeyEvent *e );
 
     /**
      * Updates the FK index as soon as the underlying model is updated when
@@ -239,11 +252,14 @@ class GUI_EXPORT QgsRelationReferenceWidget : public QWidget
     QgsMessageBar *mMessageBar = nullptr;
     QVariantList mForeignKeys;
     QgsFeature mFeature;
+    QgsFeature mFormFeature;
     // Index of the referenced layer key
     QStringList mReferencedFields;
     bool mAllowNull = true;
     QgsHighlight *mHighlight = nullptr;
-    QgsMapToolIdentifyFeature *mMapTool = nullptr;
+    QgsMapTool *mCurrentMapTool = nullptr;
+    QObjectUniquePtr<QgsMapToolIdentifyFeature> mMapToolIdentify;
+    QObjectUniquePtr<QgsMapToolDigitizeFeature> mMapToolDigitize;
     QgsMessageBarItem *mMessageBarItem = nullptr;
     QgsAttributeForm *mReferencedAttributeForm = nullptr;
     QgsVectorLayer *mReferencedLayer = nullptr;

src/gui/editorwidgets/qgsrelationreferencewidgetwrapper.cpp

@@ -196,6 +196,7 @@ void QgsRelationReferenceWidgetWrapper::updateValues( const QVariant &val, const
   Q_ASSERT( values.count() == fieldPairs.count() );
 
   mWidget->setForeignKeys( values );
+  mWidget->setFormFeature( formFeature() );
 }
 
 void QgsRelationReferenceWidgetWrapper::setEnabled( bool enabled )

src/gui/qgsattributeeditorcontext.cpp

@@ -0,0 +1,21 @@
+/***************************************************************************
+    qgsattributeeditorcontext.cpp
+     --------------------------------------
+    Date                 : 19.8.2019
+    Copyright            : (C) 201 Julien Cabieces
+    Email                : julien dot cabieces at oslandia dot com
+ ***************************************************************************
+ *                                                                         *
+ *   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 "qgsattributeeditorcontext.h"
+
+void QgsAttributeEditorContext::setCadDockWidget( QgsAdvancedDigitizingDockWidget *cadDockWidget )
+{
+  mCadDockWidget = cadDockWidget;
+}

src/gui/qgsattributeeditorcontext.h

@@ -27,6 +27,7 @@
 #include "qgsproject.h"
 
 class QgsMapCanvas;
+class QgsAdvancedDigitizingDockWidget;
 
 /**
  * \ingroup gui
@@ -132,6 +133,22 @@ class GUI_EXPORT QgsAttributeEditorContext
      */
     inline QgsMapCanvas *mapCanvas() const { return mMapCanvas; }
 
+    /**
+     * Sets the associated CAD dock widget, \a cadDockWidget, (e.g. to be used in map tools).
+     * \note Unstable API. This method is unstable API and may be modified or removed at any time.
+     * \see cadDockWidget()
+     * \since QGIS 3.10
+     */
+    void setCadDockWidget( QgsAdvancedDigitizingDockWidget *cadDockWidget );
+
+    /**
+     * Returns the associated CAD dock widget (e.g. to be used in map tools).
+     * \note Unstable API. This method is unstable API and may be modified or removed at any time.
+     * \see setCadDockWidget()
+     * \since QGIS 3.10
+     */
+    QgsAdvancedDigitizingDockWidget *cadDockWidget() const { return mCadDockWidget; }
+
     /**
      * Sets the associated vector layer tools.
      * \param vlTools vector layer tools
@@ -247,6 +264,7 @@ class GUI_EXPORT QgsAttributeEditorContext
     QgsVectorLayer *mLayer = nullptr;
     QgsVectorLayerTools *mVectorLayerTools = nullptr;
     QgsMapCanvas *mMapCanvas = nullptr;
+    QgsAdvancedDigitizingDockWidget *mCadDockWidget = nullptr;
     QgsDistanceArea mDistanceArea;
     QgsRelation mRelation;
     RelationMode mRelationMode = Undefined;
@@ -258,4 +276,3 @@ class GUI_EXPORT QgsAttributeEditorContext
 };
 
 #endif // QGSATTRIBUTEEDITORCONTEXT_H
-

src/gui/qgsmaptooldigitizefeature.cpp

@@ -31,22 +31,19 @@
 #include "qgsvectordataprovider.h"
 #include "qgsvectorlayer.h"
 #include "qgslogger.h"
-#include "qgsfeatureaction.h"
-#include "qgisapp.h"
 
 #include <QSettings>
 
-QgsMapToolDigitizeFeature::QgsMapToolDigitizeFeature( QgsMapCanvas *canvas, QgsMapLayer *layer, CaptureMode mode )
-  : QgsMapToolCapture( canvas, QgisApp::instance()->cadDockWidget(), mode )
+QgsMapToolDigitizeFeature::QgsMapToolDigitizeFeature( QgsMapCanvas *canvas, QgsAdvancedDigitizingDockWidget *cadDockWidget, CaptureMode mode )
+  : QgsMapToolCapture( canvas, cadDockWidget, mode )
   , mCheckGeometryType( true )
 {
-  mLayer = layer;
   mToolName = tr( "Digitize feature" );
-  connect( QgisApp::instance(), &QgisApp::newProject, this, &QgsMapToolDigitizeFeature::stopCapturing );
-  connect( QgisApp::instance(), &QgisApp::projectRead, this, &QgsMapToolDigitizeFeature::stopCapturing );
+  connect( QgsProject::instance(), &QgsProject::cleared, this, &QgsMapToolDigitizeFeature::stopCapturing );
+  connect( QgsProject::instance(), &QgsProject::readProject, this, &QgsMapToolDigitizeFeature::stopCapturing );
 }
 
-void QgsMapToolDigitizeFeature::digitized( QgsFeature &f )
+void QgsMapToolDigitizeFeature::digitized( const QgsFeature &f )
 {
   emit digitizingCompleted( f );
 }
@@ -344,3 +341,8 @@ void QgsMapToolDigitizeFeature::cadCanvasReleaseEvent( QgsMapMouseEvent *e )
     }
   }
 }
+
+void QgsMapToolDigitizeFeature::setLayer( QgsMapLayer *vl )
+{
+  mLayer = vl;
+}

src/gui/qgsmaptooldigitizefeature.h

@@ -17,27 +17,54 @@
 #define QGSMAPTOOLDIGITIZEFEATURE_H
 
 #include "qgsmaptoolcapture.h"
-#include "qgis_app.h"
+#include "qgis_gui.h"
 
 class QgsFeature;
 
-//! This tool digitizes geometry of new point/line/polygon features on already existing vector layers
-class APP_EXPORT QgsMapToolDigitizeFeature : public QgsMapToolCapture
+/**
+ * \ingroup gui
+ * \brief This tool digitizes geometry of new point/line/polygon features on already existing vector layers
+ * Once the map tool is enabled, user can digitize the feature geometry.
+ * A signal will then be emitted.
+ * \since QGIS 3.10
+ */
+class GUI_EXPORT QgsMapToolDigitizeFeature : public QgsMapToolCapture
 {
     Q_OBJECT
+
   public:
-    //! \since QGIS 3.2
-    QgsMapToolDigitizeFeature( QgsMapCanvas *canvas, QgsMapLayer *layer, CaptureMode mode );
+
+    /**
+     * \brief QgsMapToolDigitizeFeature is a map tool to digitize a feature geometry
+     * \param canvas the map canvas
+     * \param cadDockWidget widget to setup advanced digitizing parameters
+     * \param mode type of geometry to capture (point/line/polygon), QgsMapToolCapture::CaptureNone to autodetect geometry
+     */
+    QgsMapToolDigitizeFeature( QgsMapCanvas *canvas, QgsAdvancedDigitizingDockWidget *cadDockWidget, CaptureMode mode = QgsMapToolCapture::CaptureNone );
 
     void cadCanvasReleaseEvent( QgsMapMouseEvent *e ) override;
 
-    virtual void digitized( QgsFeature &f );
+    /**
+     * Change the layer edited by the map tool
+     * \param vl the layer to be edited by the map tool
+     */
+    void setLayer( QgsMapLayer *vl );
 
     void activate() override;
     void deactivate() override;
 
   signals:
-    void digitizingCompleted( const QgsFeature & );
+
+    /**
+     * Emitted whenever the digitizing has been successfully completed
+     * \param feature the new digitized feature
+     */
+    void digitizingCompleted( const QgsFeature &feature );
+
+    /**
+     * Emitted whenever the digitizing has been ended without digitizing
+     * any feature
+     */
     void digitizingFinished( );
 
   protected:
@@ -56,6 +83,12 @@ class APP_EXPORT QgsMapToolDigitizeFeature : public QgsMapToolCapture
 
   private:
 
+    /**
+     * Called when the feature has been digitized.
+     * \param f the new created feature
+     */
+    virtual void digitized( const QgsFeature &f );
+
     /**
      * individual layer per digitizing session
      * \since QGIS 3.0 */
@@ -70,6 +103,8 @@ class APP_EXPORT QgsMapToolDigitizeFeature : public QgsMapToolCapture
      * Check if CaptureMode matches layer type. Default is true.
      * \since QGIS 2.12 */
     bool mCheckGeometryType;
+
+    friend class TestQgsRelationReferenceWidget;
 };
 
 #endif // QGSMAPTOOLDIGITIZEFEATURE_H

src/gui/qgsmaptooledit.cpp

@@ -88,7 +88,7 @@ QgsRubberBand *QgsMapToolEdit::createRubberBand( QgsWkbTypes::GeometryType geome
 
 QgsVectorLayer *QgsMapToolEdit::currentVectorLayer()
 {
-  return qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );
+  return mCanvas ? qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() ) : nullptr;
 }
 
 

tests/src/gui/testqgsrelationreferencewidget.cpp

@@ -30,6 +30,8 @@
 #include "qgsgui.h"
 #include "qgsmapcanvas.h"
 #include "qgsvectorlayertools.h"
+#include "qgsadvanceddigitizingdockwidget.h"
+#include "qgsmaptooldigitizefeature.h"
 
 class TestQgsRelationReferenceWidget : public QObject
 {
@@ -50,6 +52,7 @@ class TestQgsRelationReferenceWidget : public QObject
     void testSetGetForeignKey();
     void testIdentifyOnMap();
     void testAddEntry();
+    void testAddEntryNoGeom();
 
   private:
     std::unique_ptr<QgsVectorLayer> mLayer1;
@@ -376,50 +379,98 @@ void TestQgsRelationReferenceWidget::testIdentifyOnMap()
   mLayer1->rollBack();
 }
 
+// Monkey patch gui vector layer tool in order to simple add a new feature in
+// referenced layer
+class DummyVectorLayerTools : public QgsVectorLayerTools
+{
+    bool addFeature( QgsVectorLayer *layer, const QgsAttributeMap &, const QgsGeometry &, QgsFeature *feat = nullptr ) const override
+    {
+      feat->setAttribute( QStringLiteral( "pk" ), 13 );
+      feat->setAttribute( QStringLiteral( "material" ), QStringLiteral( "steel" ) );
+      feat->setAttribute( QStringLiteral( "diameter" ), 140 );
+      feat->setAttribute( QStringLiteral( "raccord" ), "collar" );
+      layer->addFeature( *feat );
+      return true;
+    }
+
+    bool startEditing( QgsVectorLayer * ) const override {return true;}
+
+    bool stopEditing( QgsVectorLayer *, bool = true ) const override {return true;};
+
+    bool saveEdits( QgsVectorLayer * ) const override {return true;};
+};
 
 void TestQgsRelationReferenceWidget::testAddEntry()
 {
   // check that a new added entry in referenced layer populate correctly the
   // referencing combobox
-  QWidget parentWidget;
-  QgsRelationReferenceWidget w( &parentWidget );
+  QgsMapCanvas canvas;
+  QgsRelationReferenceWidget w( &canvas );
   QVERIFY( mLayer1->startEditing() );
   w.setRelation( *mRelation, true );
   w.init();
 
-  // Monkey patch gui vector layer tool in order to simple add a new feature in
-  // referenced layer
-  class DummyVectorLayerTools : public QgsVectorLayerTools
-  {
-      bool addFeature( QgsVectorLayer *layer, const QgsAttributeMap &, const QgsGeometry &, QgsFeature *feat = nullptr ) const override
-      {
-        feat->setAttribute( QStringLiteral( "pk" ), 13 );
-        feat->setAttribute( QStringLiteral( "material" ), "steel" );
-        feat->setAttribute( QStringLiteral( "diameter" ), 140 );
-        feat->setAttribute( QStringLiteral( "raccord" ), "collar" );
-        layer->addFeature( *feat );
-        return true;
-      }
-
-      bool startEditing( QgsVectorLayer * ) const override {return true;}
-
-      bool stopEditing( QgsVectorLayer *, bool = true ) const override {return true;}
-
-      bool saveEdits( QgsVectorLayer * ) const override {return true;}
-  };
-
+  QgsAdvancedDigitizingDockWidget cadDockWidget( &canvas );
   QgsAttributeEditorContext context;
   DummyVectorLayerTools tools;
   context.setVectorLayerTools( &tools );
-  w.setEditorContext( context, nullptr, nullptr );
+  context.setCadDockWidget( &cadDockWidget );
+  w.setEditorContext( context, &canvas, nullptr );
   w.addEntry();
 
-  Q_NOWARN_DEPRECATED_PUSH
-  QCOMPARE( w.mComboBox->identifierValue().toInt(), 13 );
-  Q_NOWARN_DEPRECATED_POP
+  QVERIFY( w.mCurrentMapTool );
+  QgsFeature feat( mLayer1->fields() );
+  w.mMapToolDigitize->digitized( feat );
+
+  QCOMPARE( w.mComboBox->identifierValues().at( 0 ).toInt(), 13 );
 }
 
+void TestQgsRelationReferenceWidget::testAddEntryNoGeom()
+{
+  QgsVectorLayer mLayer1( QStringLiteral( "Point?crs=epsg:3111&field=pk:int&field=fk:int" ), QStringLiteral( "vl1" ), QStringLiteral( "memory" ) );
+  QgsProject::instance()->addMapLayer( &mLayer1, false, false );
 
+  QgsVectorLayer mLayer2( QStringLiteral( "None?field=pk:int&field=material:string" ), QStringLiteral( "vl2" ), QStringLiteral( "memory" ) );
+  QgsProject::instance()->addMapLayer( &mLayer2, false, false );
+
+  // create relation
+  QgsRelation mRelation;
+  mRelation.setId( QStringLiteral( "vl1.vl2" ) );
+  mRelation.setName( QStringLiteral( "vl1.vl2" ) );
+  mRelation.setReferencingLayer( mLayer1.id() );
+  mRelation.setReferencedLayer( mLayer2.id() );
+  mRelation.addFieldPair( QStringLiteral( "fk" ), QStringLiteral( "pk" ) );
+  QVERIFY( mRelation.isValid() );
+  QgsProject::instance()->relationManager()->addRelation( mRelation );
+
+  // add feature
+  QgsFeature ft0( mLayer1.fields() );
+  ft0.setAttribute( QStringLiteral( "pk" ), 0 );
+  ft0.setAttribute( QStringLiteral( "fk" ), 0 );
+  mLayer1.startEditing();
+  mLayer1.addFeature( ft0 );
+  mLayer1.commitChanges();
+
+  // check that a new added entry in referenced layer populate correctly the
+  // referencing combobox
+  QgsMapCanvas canvas;
+  QgsRelationReferenceWidget w( &canvas );
+  QVERIFY( mLayer1.startEditing() );
+  w.setRelation( mRelation, true );
+  w.init();
+
+  QgsAdvancedDigitizingDockWidget cadDockWidget( &canvas );
+  QgsAttributeEditorContext context;
+  DummyVectorLayerTools tools;
+  context.setVectorLayerTools( &tools );
+  context.setCadDockWidget( &cadDockWidget );
+  w.setEditorContext( context, &canvas, nullptr );
+  w.addEntry();
+
+  QVERIFY( !w.mCurrentMapTool );
+
+  QCOMPARE( w.mComboBox->identifierValues().at( 0 ).toInt(), 13 );
+}
 
 QGSTEST_MAIN( TestQgsRelationReferenceWidget )
 #include "testqgsrelationreferencewidget.moc"

tests/src/python/test_qgsattributeform.py

@@ -28,6 +28,7 @@ from qgis.gui import (
     QgsAttributeForm,
     QgsGui,
     QgsEditorWidgetWrapper,
+    QgsMapCanvas
 )
 
 
@@ -38,7 +39,8 @@ class TestQgsAttributeForm(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
-        QgsGui.editorWidgetRegistry().initEditors()
+        cls.mCanvas = QgsMapCanvas()
+        QgsGui.editorWidgetRegistry().initEditors(cls.mCanvas)
 
     @classmethod
     def createLayerWithOnePoint(cls, field_type):