QGIS API Documentation  3.4.3-Madeira (2f64a3c)
Public Member Functions | List of all members
QgsFieldFormatter Class Referenceabstract

A field formatter helps to handle and display values for a field. More...

#include <qgsfieldformatter.h>

Inheritance diagram for QgsFieldFormatter:
Inheritance graph
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Public Member Functions

 QgsFieldFormatter ()
 
virtual ~QgsFieldFormatter ()=default
 
virtual Qt::AlignmentFlag alignmentFlag (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config) const
 Returns the alignment for a particular field. More...
 
virtual QVariant createCache (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config) const
 Create a cache for a given field. More...
 
virtual QString id () const =0
 Returns a unique id for this field formatter. More...
 
virtual QString representValue (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config, const QVariant &cache, const QVariant &value) const
 Create a pretty String representation of the value. More...
 
virtual QVariant sortValue (QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config, const QVariant &cache, const QVariant &value) const
 If the default sort order should be overwritten for this widget, you can transform the value in here. More...
 

Detailed Description

A field formatter helps to handle and display values for a field.

It allows for using a shared configuration with the editor widgets for representation of attribute values. Field kits normally have one single instance which is managed by the QgsFieldFormatterRegistry. Custom field formatters should be registered there and field formatters for use within code should normally be obtained from there.

This is an abstract base class and will always need to be subclassed.

Since
QGIS 3.0

Definition at line 40 of file qgsfieldformatter.h.

Constructor & Destructor Documentation

◆ QgsFieldFormatter()

QgsFieldFormatter::QgsFieldFormatter ( )

Definition at line 22 of file qgsfieldformatter.cpp.

◆ ~QgsFieldFormatter()

virtual QgsFieldFormatter::~QgsFieldFormatter ( )
virtualdefault

Member Function Documentation

◆ alignmentFlag()

Qt::AlignmentFlag QgsFieldFormatter::alignmentFlag ( QgsVectorLayer layer,
int  fieldIndex,
const QVariantMap &  config 
) const
virtual

Returns the alignment for a particular field.

By default this will consider the field type but can be overwritten if mapped values are represented.

Since
QGIS 3.0

Definition at line 48 of file qgsfieldformatter.cpp.

◆ createCache()

QVariant QgsFieldFormatter::createCache ( QgsVectorLayer layer,
int  fieldIndex,
const QVariantMap &  config 
) const
virtual

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 in QgsValueRelationFieldFormatter.

Definition at line 62 of file qgsfieldformatter.cpp.

◆ id()

virtual QString QgsFieldFormatter::id ( ) const
pure virtual

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.

Implemented in QgsValueRelationFieldFormatter, QgsValueMapFieldFormatter, QgsDateTimeFieldFormatter, QgsKeyValueFieldFormatter, QgsRelationReferenceFieldFormatter, QgsListFieldFormatter, QgsFallbackFieldFormatter, and QgsRangeFieldFormatter.

◆ representValue()

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

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 in QgsValueRelationFieldFormatter, QgsValueMapFieldFormatter, QgsDateTimeFieldFormatter, QgsKeyValueFieldFormatter, QgsRelationReferenceFieldFormatter, QgsListFieldFormatter, and QgsRangeFieldFormatter.

Definition at line 26 of file qgsfieldformatter.cpp.

◆ sortValue()

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

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 in QgsValueRelationFieldFormatter, QgsValueMapFieldFormatter, and QgsRelationReferenceFieldFormatter.

Definition at line 38 of file qgsfieldformatter.cpp.


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