Field formatter for a value relation field. More...

#include <qgsvaluerelationfieldformatter.h>

Inheritance diagram for QgsValueRelationFieldFormatter:

Classes
struct	ValueRelationItem

Public Types
typedef QVector< QgsValueRelationFieldFormatter::ValueRelationItem >	ValueRelationCache

Public Types inherited from QgsFieldFormatter
typedef QFlags< Flag >	Flags

Public Member Functions
	QgsValueRelationFieldFormatter ()
	Constructor for QgsValueRelationFieldFormatter.

QVariantList	availableValues (const QVariantMap &config, int countLimit, const QgsFieldFormatterContext &context) const override
	Returns a list of the values that would be possible to select with this widget type On a RelationReference that would be the parents ids or on ValueMap all the configured keys according to the settings in the config.

QVariant	createCache (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config) const override
	Create a cache for a given field.

QString	id () const override
	Returns a unique id for this field formatter.

QList< QgsVectorLayerRef >	layerDependencies (const QVariantMap &config) const override
	Returns a list of weak layer references to other layers required by this formatter for the given config.

QString	representValue (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config, const QVariant &cache, const QVariant &value) const override
	Create a pretty String representation of the value.

QVariant	sortValue (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config, const QVariant &cache, const QVariant &value) const override
	If the default sort order should be overwritten for this widget, you can transform the value in here.

Public Member Functions inherited from QgsFieldFormatter
	QgsFieldFormatter ()=default

virtual	~QgsFieldFormatter ()=default

virtual Qt::AlignmentFlag	alignmentFlag (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config) const
	Returns the alignment for a particular field.

Flags	flags () const
	Returns the flags.

void	setFlags (const Flags &flags)
	Sets the flags.

enum Flag	SIP_ENUM_BASETYPE (IntFlag)
	Flags for the abilities of the formatter.

Static Public Member Functions
static QgsValueRelationFieldFormatter::ValueRelationCache	createCache (const QVariantMap &config, const QgsFeature &formFeature=QgsFeature(), const QgsFeature &parentFormFeature=QgsFeature())
	Create a cache for a value relation field.

static QSet< QString >	expressionFormAttributes (const QString &expression)
	Returns a list of attributes required by the form context expression.

static QSet< QString >	expressionFormVariables (const QString &expression)
	Returns a list of variables required by the form context expression.

static bool	expressionIsUsable (const QString &expression, const QgsFeature &feature, const QgsFeature &parentFeature=QgsFeature())
	Check whether the feature has all values required by the expression, optionally checks for parentFeature.

static QSet< QString >	expressionParentFormAttributes (const QString &expression)
	Returns a list of attributes required by the parent form's form context expression.

static QSet< QString >	expressionParentFormVariables (const QString &expression)
	Returns a list of variables required by the parent form's form context expression.

static bool	expressionRequiresFormScope (const QString &expression)
	Check if the expression requires a form scope (i.e.

static bool	expressionRequiresParentFormScope (const QString &expression)
	Check if the expression requires a parent form scope (i.e.

static QgsVectorLayer *	resolveLayer (const QVariantMap &config, const QgsProject *project)
	Returns the (possibly `nullptr`) layer from the widget's config and project.

static QStringList	valueToStringList (const QVariant &value)
	Utility to convert a list or a string representation of an (hstore style: {1,2...}) list in value to a string list.

Detailed Description

Field formatter for a value relation field.

A value relation field formatter looks up the values from features on another layer.

Definition at line 36 of file qgsvaluerelationfieldformatter.h.

Member Typedef Documentation

◆ ValueRelationCache

typedef QVector< QgsValueRelationFieldFormatter::ValueRelationItem > QgsValueRelationFieldFormatter::ValueRelationCache

Definition at line 58 of file qgsvaluerelationfieldformatter.h.

Constructor & Destructor Documentation

◆ QgsValueRelationFieldFormatter()

QgsValueRelationFieldFormatter::QgsValueRelationFieldFormatter ( )

Constructor for QgsValueRelationFieldFormatter.

Definition at line 34 of file qgsvaluerelationfieldformatter.cpp.

Member Function Documentation

◆ availableValues()

QVariantList QgsValueRelationFieldFormatter::availableValues	(	const QVariantMap &	config,
		int	countLimit,
		const QgsFieldFormatterContext &	context
	)		const

overridevirtual

Returns a list of the values that would be possible to select with this widget type On a RelationReference that would be the parents ids or on ValueMap all the configured keys according to the settings in the config.

Since: QGIS 3.12

Reimplemented from QgsFieldFormatter.

Definition at line 246 of file qgsvaluerelationfieldformatter.cpp.

◆ createCache() [1/2]

QgsValueRelationFieldFormatter::ValueRelationCache QgsValueRelationFieldFormatter::createCache	(	const QVariantMap &	config,
		const QgsFeature &	formFeature = `QgsFeature()`,
		const QgsFeature &	parentFormFeature = `QgsFeature()`
	)

static

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.

Parameters

config	The widget configuration
formFeature	The feature currently being edited with current attribute values
parentFormFeature	For embedded forms only, the feature currently being edited in the parent form with current attribute values

Returns: A kvp list of values for the widget

Definition at line 115 of file qgsvaluerelationfieldformatter.cpp.

◆ createCache() [2/2]

QVariant QgsValueRelationFieldFormatter::createCache	(	QgsVectorLayer *	layer,
		int	fieldIndex,
		const QVariantMap &	config
	)		const

overridevirtual

Create a cache for a given field.

This will be used in situations where a field is being represented various times in a loop. And will be passed to other methods on QgsFieldKit and QgsEditorWidgetWrapper.

For example, the attribute table will create a cache once for each field and then use this cache for representation. The QgsValueRelationFieldFormatter and QgsValueRelationEditorWidget implement this functionality to create a lookuptable once (a QVariantMap / dict) and are make use of a cache if present.

Reimplemented from QgsFieldFormatter.

Definition at line 107 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionFormAttributes()

QSet< QString > QgsValueRelationFieldFormatter::expressionFormAttributes ( const QString & expression )

static

Returns a list of attributes required by the form context expression.

Parameters

expression Form filter expression

Returns: list of attributes required by the expression

Since: QGIS 3.2

Definition at line 378 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionFormVariables()

QSet< QString > QgsValueRelationFieldFormatter::expressionFormVariables ( const QString & expression )

static

Returns a list of variables required by the form context expression.

Parameters

expression Form filter expression

Returns: list of variables required by the expression

Since: QGIS 3.2

Definition at line 325 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionIsUsable()

bool QgsValueRelationFieldFormatter::expressionIsUsable	(	const QString &	expression,
		const QgsFeature &	feature,
		const QgsFeature &	parentFeature = `QgsFeature()`
	)

static

Check whether the feature has all values required by the expression, optionally checks for parentFeature.

Returns: true if the expression can be used

Since: QGIS 3.2

Definition at line 403 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionParentFormAttributes()

QSet< QString > QgsValueRelationFieldFormatter::expressionParentFormAttributes ( const QString & expression )

static

Returns a list of attributes required by the parent form's form context expression.

Parameters

expression Form filter expression

Returns: list of parent attributes required by the expression

Since: QGIS 3.14

Definition at line 353 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionParentFormVariables()

QSet< QString > QgsValueRelationFieldFormatter::expressionParentFormVariables ( const QString & expression )

static

Returns a list of variables required by the parent form's form context expression.

Parameters

expression Form filter expression

Returns: list of parent variables required by the expression

Since: QGIS 3.14

Definition at line 334 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionRequiresFormScope()

bool QgsValueRelationFieldFormatter::expressionRequiresFormScope ( const QString & expression )

static

Check if the expression requires a form scope (i.e.

if it uses fields or geometry of the currently edited feature).

Parameters

expression The widget's filter expression

Returns: true if the expression requires a form scope

Since: QGIS 3.2

Definition at line 343 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionRequiresParentFormScope()

bool QgsValueRelationFieldFormatter::expressionRequiresParentFormScope ( const QString & expression )

static

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).

Parameters

expression The widget's filter expression

Returns: true if the expression requires a parent form scope

Since: QGIS 3.14

Definition at line 348 of file qgsvaluerelationfieldformatter.cpp.

◆ id()

QString QgsValueRelationFieldFormatter::id ( ) const

overridevirtual

Returns a unique id for this field formatter.

This id will later be used to identify this field formatter in the registry with QgsFieldFormatterRegistry::fieldFormatter().

This id matches the id of a QgsEditorWidgetFactory.

Implements QgsFieldFormatter.

Definition at line 39 of file qgsvaluerelationfieldformatter.cpp.

◆ layerDependencies()

QList< QgsVectorLayerRef > QgsValueRelationFieldFormatter::layerDependencies ( const QVariantMap & config ) const

overridevirtual

Returns a list of weak layer references to other layers required by this formatter for the given config.

The default implementation returns an empty list.

This method should be reimplemented by formatters that handle relations with other layers, (e.g. ValueRelation) and can be used by client code to warn the user about missing required dependencies or to add some resolution logic in order to load the missing dependency.

Note: not available in Python bindings

Since: QGIS 3.12

Reimplemented from QgsFieldFormatter.

Definition at line 232 of file qgsvaluerelationfieldformatter.cpp.

◆ representValue()

QString QgsValueRelationFieldFormatter::representValue	(	QgsVectorLayer *	layer,
		int	fieldIndex,
		const QVariantMap &	config,
		const QVariant &	cache,
		const QVariant &	value
	)		const

overridevirtual

Create a pretty String representation of the value.

Returns: By default the string representation of the provided value as implied by the field definition is returned.

Reimplemented from QgsFieldFormatter.

Definition at line 44 of file qgsvaluerelationfieldformatter.cpp.

◆ resolveLayer()

QgsVectorLayer * QgsValueRelationFieldFormatter::resolveLayer	(	const QVariantMap &	config,
		const QgsProject *	project
	)

static

Returns the (possibly nullptr) layer from the widget's config and project.

Since: QGIS 3.8

Definition at line 431 of file qgsvaluerelationfieldformatter.cpp.

◆ sortValue()

QVariant QgsValueRelationFieldFormatter::sortValue	(	QgsVectorLayer *	layer,
		int	fieldIndex,
		const QVariantMap &	config,
		const QVariant &	cache,
		const QVariant &	value
	)		const

overridevirtual

If the default sort order should be overwritten for this widget, you can transform the value in here.

Returns: an unmodified value by default.

Reimplemented from QgsFieldFormatter.

Definition at line 102 of file qgsvaluerelationfieldformatter.cpp.

◆ valueToStringList()

QStringList QgsValueRelationFieldFormatter::valueToStringList ( const QVariant & value )

static

Utility to convert a list or a string representation of an (hstore style: {1,2...}) list in value to a string list.

Since: QGIS 3.2

Definition at line 262 of file qgsvaluerelationfieldformatter.cpp.

The documentation for this class was generated from the following files:

/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/fieldformatter/qgsvaluerelationfieldformatter.h
/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/fieldformatter/qgsvaluerelationfieldformatter.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Typedef Documentation

◆ ValueRelationCache

Constructor & Destructor Documentation

◆ QgsValueRelationFieldFormatter()

Member Function Documentation

◆ availableValues()

◆ createCache() [1/2]

◆ createCache() [2/2]

◆ expressionFormAttributes()

◆ expressionFormVariables()

◆ expressionIsUsable()

◆ expressionParentFormAttributes()

◆ expressionParentFormVariables()

◆ expressionRequiresFormScope()

◆ expressionRequiresParentFormScope()

◆ id()

◆ layerDependencies()

◆ representValue()

◆ resolveLayer()

◆ sortValue()

◆ valueToStringList()