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 Member Functions
	QgsValueRelationFieldFormatter ()=default
	Constructor for QgsValueRelationFieldFormatter. More...

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

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

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. More...

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. More...

Public Member Functions inherited from QgsFieldFormatter
	QgsFieldFormatter ()=default
	Default constructor. More...

virtual	~QgsFieldFormatter ()=default

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

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

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

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

static bool	expressionIsUsable (const QString &expression, const QgsFeature &feature)
	Check whether the feature has all values required by the expression. More...

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

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

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. More...

Detailed Description

Field formatter for a value relation field.

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

Since: QGIS 3.0

Definition at line 36 of file qgsvaluerelationfieldformatter.h.

Member Typedef Documentation

◆ ValueRelationCache

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

Definition at line 54 of file qgsvaluerelationfieldformatter.h.

Constructor & Destructor Documentation

◆ QgsValueRelationFieldFormatter()

QgsValueRelationFieldFormatter::QgsValueRelationFieldFormatter ( )

default

Constructor for QgsValueRelationFieldFormatter.

Member Function Documentation

◆ createCache() [1/2]

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.

Since: QGIS 3.0

Reimplemented from QgsFieldFormatter.

Definition at line 111 of file qgsvaluerelationfieldformatter.cpp.

◆ createCache() [2/2]

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

Returns: A kvp list of values for the widget

Since: QGIS 3.0

Definition at line 119 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 248 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 234 of file qgsvaluerelationfieldformatter.cpp.

◆ expressionIsUsable()

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

static

Check whether the feature has all values required by the expression.

Returns: true if the expression can be used

Since: QGIS 3.2

Definition at line 273 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 243 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 43 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.

Since: QGIS 3.0

Reimplemented from QgsFieldFormatter.

Definition at line 48 of file qgsvaluerelationfieldformatter.cpp.

◆ resolveLayer()

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

static

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

Since: QGIS 3.8

Definition at line 286 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.

Since: QGIS 3.0

Reimplemented from QgsFieldFormatter.

Definition at line 106 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 171 of file qgsvaluerelationfieldformatter.cpp.

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

/build/qgis-3.10.0+15buster/src/core/fieldformatter/qgsvaluerelationfieldformatter.h
/build/qgis-3.10.0+15buster/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

◆ createCache() [1/2]

◆ createCache() [2/2]

◆ expressionFormAttributes()

◆ expressionFormVariables()

◆ expressionIsUsable()

◆ expressionRequiresFormScope()

◆ id()

◆ representValue()

◆ resolveLayer()

◆ sortValue()

◆ valueToStringList()