Merge pull request #34827 from elpaso/parent-form-current-value-2

[feature] Get current parent form values in child forms
qgis · Mar 5, 2020 · 3246a92 · 3246a92
2 parents 0c3f233 + 60e9ed4
commit 3246a92
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Showing 34 changed files with 547 additions and 26 deletions.
diff --git a/python/core/auto_generated/expression/qgsexpressioncontextutils.sip.in b/python/core/auto_generated/expression/qgsexpressioncontextutils.sip.in
@@ -33,11 +33,20 @@ For instance, QGIS version numbers and variables specified through QGIS options.
 
     static QgsExpressionContextScope *formScope( const QgsFeature &formFeature = QgsFeature( ), const QString &formMode = QString() ) /Factory/;
 %Docstring
-Creates a new scope which contains functions and variables from the current attribute form/table ``feature``.
+Creates a new scope which contains functions and variables from the current attribute form/table ``formFeature``.
 The variables and values in this scope will reflect the current state of the form/row being edited.
 The ``formMode`` (SingleEditMode etc.) is passed as text
 
 .. versionadded:: 3.2
+%End
+
+    static QgsExpressionContextScope *parentFormScope( const QgsFeature &formFeature = QgsFeature( ), const QString &formMode = QString() ) /Factory/;
+%Docstring
+Creates a new scope which contains functions and variables from the current parent attribute form/table ``formFeature``.
+The variables and values in this scope will reflect the current state of the parent form/row being edited.
+The ``formMode`` (SingleEditMode etc.) is passed as text
+
+.. versionadded:: 3.14
 %End
 
     static void setGlobalVariable( const QString &name, const QVariant &value );

diff --git a/python/core/auto_generated/fieldformatter/qgsvaluerelationfieldformatter.sip.in b/python/core/auto_generated/fieldformatter/qgsvaluerelationfieldformatter.sip.in
@@ -64,14 +64,15 @@ Utility to convert a list or a string representation of an (hstore style: {1,2..
 .. versionadded:: 3.2
 %End
 
-    static QgsValueRelationFieldFormatter::ValueRelationCache createCache( const QVariantMap &config, const QgsFeature &formFeature = QgsFeature() );
+    static QgsValueRelationFieldFormatter::ValueRelationCache createCache( const QVariantMap &config, const QgsFeature &formFeature = QgsFeature(), const QgsFeature &parentFormFeature = QgsFeature() );
 %Docstring
 Create a cache for a value relation field.
 This can be used to keep the value map in the local memory
 if doing multiple lookups in a loop.
 
 :param config: The widget configuration
 :param formFeature: The feature currently being edited with current attribute values
+:param parentFormFeature: For embedded forms only, the feature currently being edited in the parent form with current attribute values
 
 :return: A kvp list of values for the widget
 
@@ -112,9 +113,45 @@ Returns a list of variables required by the form context ``expression``
 .. versionadded:: 3.2
 %End
 
-    static bool expressionIsUsable( const QString &expression, const QgsFeature &feature );
+    static bool expressionRequiresParentFormScope( const QString &expression );
 %Docstring
-Check whether the ``feature`` has all values required by the ``expression``
+Check if the ``expression`` requires a parent form scope (i.e. if it uses fields
+or geometry of the parent form's currently edited feature).
+
+:param expression: The widget's filter expression
+
+:return: ``True`` if the expression requires a parent form scope
+
+.. versionadded:: 3.14
+%End
+
+    static QSet<QString> expressionParentFormAttributes( const QString &expression );
+%Docstring
+Returns a list of attributes required by the parent form's form context ``expression``
+
+:param expression: Form filter expression
+
+:return: list of parent attributes required by the expression
+
+.. versionadded:: 3.14
+%End
+
+    static QSet<QString> expressionParentFormVariables( const QString &expression );
+%Docstring
+Returns a list of variables required by the parent form's form context ``expression``
+
+:param expression: Form filter expression
+
+:return: list of parent variables required by the expression
+
+.. versionadded:: 3.14
+%End
+
+
+    static bool expressionIsUsable( const QString &expression, const QgsFeature &feature, const QgsFeature &parentFeature = QgsFeature() );
+%Docstring
+Check whether the ``feature`` has all values required by the ``expression``,
+optionally checks for ``parentFeature``
 
 :return: ``True`` if the expression can be used
 

diff --git a/python/gui/auto_generated/attributetable/qgsattributetableview.sip.in b/python/gui/auto_generated/attributetable/qgsattributetableview.sip.in
@@ -69,6 +69,7 @@ Returns the selected features in the attribute table in table sorted order.
 .. versionadded:: 3.4
 %End
 
+
   protected:
 
     virtual void mousePressEvent( QMouseEvent *event );

diff --git a/python/gui/auto_generated/attributetable/qgsdualview.sip.in b/python/gui/auto_generated/attributetable/qgsdualview.sip.in
@@ -232,6 +232,16 @@ Copy the content of the selected cell in the clipboard.
 Cancel the progress dialog (if any)
 
 .. versionadded:: 3.0
+%End
+
+    void parentFormValueChanged( const QString &attribute, const QVariant &value );
+%Docstring
+Called in embedded forms when an ``attribute`` ``value`` in the parent form has changed.
+
+Notify the form widgets that something has changed in case they
+have filter expression that depend on the parent form scope.
+
+.. versionadded:: 3.14
 %End
 
   signals:

diff --git a/python/gui/auto_generated/editorwidgets/core/qgseditorwidgetwrapper.sip.in b/python/gui/auto_generated/editorwidgets/core/qgseditorwidgetwrapper.sip.in
@@ -302,6 +302,19 @@ to reflect the new values.
     void emitValueChanged();
 %Docstring
 Will call the value() method to determine the emitted value
+%End
+
+    virtual void parentFormValueChanged( const QString &attribute, const QVariant &value );
+%Docstring
+Is called in embedded form widgets when an ``attribute`` ``value`` in
+the parent form has changed.
+
+The default implementations does nothing.
+Subclasses should reimplement this method to notify the form widgets
+that something has changed in case they have filter expressions that
+depend on the parent form scope.
+
+.. versionadded:: 3.14
 %End
 
   protected:

diff --git a/python/gui/auto_generated/editorwidgets/qgsrelationwidgetwrapper.sip.in b/python/gui/auto_generated/editorwidgets/qgsrelationwidgetwrapper.sip.in
@@ -88,6 +88,21 @@ The relation for which this wrapper is created.
 .. versionadded:: 3.0
 %End
 
+    void widgetValueChanged( const QString &attribute, const QVariant &newValue, bool attributeChanged );
+%Docstring
+Will be called when a value in the current edited form or table row
+changes
+
+Forward the signal to the embedded form
+
+:param attribute: The name of the attribute that changed.
+:param newValue: The new value of the attribute.
+:param attributeChanged: If ``True``, it corresponds to an actual change of the feature attribute
+
+.. versionadded:: 3.14
+%End
+
+
   protected:
     virtual QWidget *createWidget( QWidget *parent );
 

diff --git a/python/gui/auto_generated/qgsattributeeditorcontext.sip.in b/python/gui/auto_generated/qgsattributeeditorcontext.sip.in
@@ -235,6 +235,24 @@ Set current ``feature`` for the currently edited form or table row
 .. seealso:: :py:func:`formFeature`
 
 .. versionadded:: 3.2
+%End
+
+    QgsFeature parentFormFeature() const;
+%Docstring
+Returns the feature of the currently edited parent form in its actual state
+
+.. seealso:: :py:func:`setParentFormFeature`
+
+.. versionadded:: 3.14
+%End
+
+    void setParentFormFeature( const QgsFeature &feature );
+%Docstring
+Sets the ``feature`` of the currently edited parent form
+
+.. seealso:: :py:func:`parentFormFeature`
+
+.. versionadded:: 3.14
 %End
 
     Mode attributeFormMode() const;

diff --git a/python/gui/auto_generated/qgsattributeform.sip.in b/python/gui/auto_generated/qgsattributeform.sip.in
@@ -280,6 +280,18 @@ Resets the search/filter form values.
 reload current feature
 %End
 
+    void parentFormValueChanged( const QString &attribute, const QVariant &newValue );
+%Docstring
+Is called in embedded forms when an ``attribute`` value in the parent form
+has changed to ``newValue``.
+
+Notify the form widgets that something has changed in case they
+have filter expressions that depend on the parent form scope.
+
+.. versionadded:: 3.14
+%End
+
+
 };
 
 

diff --git a/python/gui/auto_generated/qgsrelationeditorwidget.sip.in b/python/gui/auto_generated/qgsrelationeditorwidget.sip.in
@@ -51,6 +51,9 @@ Gets the view mode for the dual view
 %End
 
     void setRelationFeature( const QgsRelation &relation, const QgsFeature &feature );
+%Docstring
+Sets the ``relation`` and the ``feature``
+%End
 
     void setRelations( const QgsRelation &relation, const QgsRelation &nmrelation );
 %Docstring
@@ -63,9 +66,15 @@ inserting and deleting entries on the intermediate table as required.
 :param nmrelation: Optional reference from the referencing table to a 3rd N:M table
 %End
 
-    void setFeature( const QgsFeature &feature );
+    void setFeature( const QgsFeature &feature, bool update = true );
+%Docstring
+Sets the ``feature`` being edited and updates the UI unless ``update`` is set to ``False``
+%End
 
     void setEditorContext( const QgsAttributeEditorContext &context );
+%Docstring
+Sets the editor ``context``
+%End
 
     QgsIFeatureSelectionManager *featureSelectionManager();
 %Docstring
@@ -129,6 +138,21 @@ Determines if the "Save child layer edits" button should be shown
 .. versionadded:: 3.14
 %End
 
+    QgsFeature feature() const;
+%Docstring
+Returns the widget's current feature
+
+.. versionadded:: 3.14
+%End
+
+  public slots:
+
+    void parentFormValueChanged( const QString &attribute, const QVariant &newValue );
+%Docstring
+Called when an ``attribute`` value in the parent widget has changed to ``newValue``
+
+.. versionadded:: 3.14
+%End
 
 };
 

diff --git a/resources/function_help/json/current_parent_value b/resources/function_help/json/current_parent_value
@@ -0,0 +1,7 @@
+{
+  "name": "current_parent_value",
+  "type": "function",
+  "description": "Only usable in an embedded form context, this function returns the current, unsaved value of a field in the parent form currently being edited. This will differ from the parent feature's actual attribute values for features which are currently being edited or have not yet been added to a parent layer. When used in a value-relation widget filter expression, this function should be wrapped into a 'coalesce()' that can retrieve the actual parent feature from the layer when the form is not used in an embedded context.",
+  "arguments": [ {"arg":"field_name","description":"a field name in the current parent form"}],
+  "examples": [ { "expression":"current_parent_value( 'FIELD_NAME' )","returns":"The current value of a field 'FIELD_NAME' in the parent form."} ]
+}
diff --git a/src/core/expression/qgsexpression.cpp b/src/core/expression/qgsexpression.cpp
@@ -826,6 +826,22 @@ void QgsExpression::initVariableHelp()
   sVariableHelpTexts()->insert( QStringLiteral( "current_geometry" ), QCoreApplication::translate( "current_geometry", "Represents the geometry of the feature currently being edited in the form or the table row. Can be used in a form/row context to filter the related features." ) );
   sVariableHelpTexts()->insert( QStringLiteral( "current_feature" ), QCoreApplication::translate( "current_feature", "Represents the feature currently being edited in the form or the table row. Can be used in a form/row context to filter the related features." ) );
 
+  //parent form context variable
+  sVariableHelpTexts()->insert( QStringLiteral( "current_parent_geometry" ), QCoreApplication::translate( "current_parent_geometry",
+                                "Only usable in an embedded form context, "
+                                "represents the geometry of the feature currently being edited in the parent form.\n"
+                                "Can be used in a form/row context to filter the related features using a value "
+                                "from the feature currently edited in the parent form, to make sure that the filter "
+                                "still works with standalone forms it is recommended to wrap this variable in a "
+                                "'coalesce()'." ) );
+  sVariableHelpTexts()->insert( QStringLiteral( "current_parent_feature" ), QCoreApplication::translate( "current_parent_feature",
+                                "Only usable in an embedded form context, "
+                                "represents the feature currently being edited in the parent form.\n"
+                                "Can be used in a form/row context to filter the related features using a value "
+                                "from the feature currently edited in the parent form, to make sure that the filter "
+                                "still works with standalone forms it is recommended to wrap this variable in a "
+                                "'coalesce()'." ) );
+
   //form variable
   sVariableHelpTexts()->insert( QStringLiteral( "form_mode" ), QCoreApplication::translate( "form_mode", "What the form is used for, like AddFeatureMode, SingleEditMode, MultiEditMode, SearchMode, AggregateSearchMode or IdentifyMode as string." ) );
 }

diff --git a/src/core/expression/qgsexpressioncontextutils.cpp b/src/core/expression/qgsexpressioncontextutils.cpp
@@ -134,6 +134,31 @@ class GetCurrentFormFieldValue : public QgsScopedExpressionFunction
 
 };
 
+class GetCurrentParentFormFieldValue : public QgsScopedExpressionFunction
+{
+  public:
+    GetCurrentParentFormFieldValue( )
+      : QgsScopedExpressionFunction( QStringLiteral( "current_parent_value" ), QgsExpressionFunction::ParameterList() << QStringLiteral( "field_name" ), QStringLiteral( "Form" ) )
+    {}
+
+    QVariant func( const QVariantList &values, const QgsExpressionContext *context, QgsExpression *, const QgsExpressionNodeFunction * ) override
+    {
+      QString fieldName( values.at( 0 ).toString() );
+      const QgsFeature feat( context->variable( QStringLiteral( "current_parent_feature" ) ).value<QgsFeature>() );
+      if ( fieldName.isEmpty() || ! feat.isValid( ) )
+      {
+        return QVariant();
+      }
+      return feat.attribute( fieldName ) ;
+    }
+
+    QgsScopedExpressionFunction *clone() const override
+    {
+      return new GetCurrentParentFormFieldValue( );
+    }
+
+};
+
 
 class GetProcessingParameterValue : public QgsScopedExpressionFunction
 {
@@ -172,6 +197,17 @@ QgsExpressionContextScope *QgsExpressionContextUtils::formScope( const QgsFeatur
   return scope;
 }
 
+
+QgsExpressionContextScope *QgsExpressionContextUtils::parentFormScope( const QgsFeature &parentFormFeature, const QString &parentFormMode )
+{
+  QgsExpressionContextScope *scope = new QgsExpressionContextScope( QObject::tr( "Parent Form" ) );
+  scope->addFunction( QStringLiteral( "current_parent_value" ), new GetCurrentParentFormFieldValue( ) );
+  scope->setVariable( QStringLiteral( "current_parent_geometry" ), parentFormFeature.geometry( ), true );
+  scope->setVariable( QStringLiteral( "current_parent_feature" ), parentFormFeature, true );
+  scope->setVariable( QStringLiteral( "parent_form_mode" ), parentFormMode, true );
+  return scope;
+}
+
 QgsExpressionContextScope *QgsExpressionContextUtils::projectScope( const QgsProject *project )
 {
   if ( !project )
@@ -766,6 +802,7 @@ void QgsExpressionContextUtils::registerContextFunctions()
   QgsExpression::registerFunction( new GetLayerVisibility( QList<QgsMapLayer *>(), 0.0 ) );
   QgsExpression::registerFunction( new GetProcessingParameterValue( QVariantMap() ) );
   QgsExpression::registerFunction( new GetCurrentFormFieldValue( ) );
+  QgsExpression::registerFunction( new GetCurrentParentFormFieldValue( ) );
 }
 
 bool QgsScopedExpressionFunction::usesGeometry( const QgsExpressionNodeFunction *node ) const

diff --git a/src/core/expression/qgsexpressioncontextutils.h b/src/core/expression/qgsexpressioncontextutils.h
@@ -54,13 +54,21 @@ class CORE_EXPORT QgsExpressionContextUtils
     static QgsExpressionContextScope *globalScope() SIP_FACTORY;
 
     /**
-     * Creates a new scope which contains functions and variables from the current attribute form/table \a feature.
+     * Creates a new scope which contains functions and variables from the current attribute form/table \a formFeature.
      * The variables and values in this scope will reflect the current state of the form/row being edited.
      * The \a formMode (SingleEditMode etc.) is passed as text
      * \since QGIS 3.2
      */
     static QgsExpressionContextScope *formScope( const QgsFeature &formFeature = QgsFeature( ), const QString &formMode = QString() ) SIP_FACTORY;
 
+    /**
+     * Creates a new scope which contains functions and variables from the current parent attribute form/table \a formFeature.
+     * The variables and values in this scope will reflect the current state of the parent form/row being edited.
+     * The \a formMode (SingleEditMode etc.) is passed as text
+     * \since QGIS 3.14
+     */
+    static QgsExpressionContextScope *parentFormScope( const QgsFeature &formFeature = QgsFeature( ), const QString &formMode = QString() ) SIP_FACTORY;
+
     /**
      * Sets a global context variable. This variable will be contained within scopes retrieved via
      * globalScope().