QgsFields Class Reference

Container of fields for a vector layer. More...

#include <qgsfield.h>

Classes
struct	Field

Public Types
enum	FieldOrigin { OriginUnknown, OriginProvider, OriginJoin, OriginEdit }
typedef struct QgsFields::Field	Field

Public Member Functions
void	clear ()
	Remove all fields.
bool	append (const QgsField &field, FieldOrigin origin=OriginProvider, int originIndex=-1)
	Append a field. The field must have unique name, otherwise it is rejected (returns false)
void	remove (int fieldIdx)
	Remove a field with the given index.
void	extend (const QgsFields &other)
	Extend with fields from another QgsFields container.
bool	isEmpty () const
	Check whether the container is empty.
int	count () const
	Return number of items.
int	size () const
	Return number of items.
bool	exists (int i) const
	Return if a field index is valid.
const QgsField &	operator[] (int i) const
	Get field at particular index (must be in range 0..N-1)
QgsField &	operator[] (int i)
	Get field at particular index (must be in range 0..N-1)
const QgsField &	at (int i) const
	Get field at particular index (must be in range 0..N-1)
const QgsField &	field (int fieldIdx) const
	Get field at particular index (must be in range 0..N-1)
const QgsField &	field (const QString &name) const
	Get field at particular index (must be in range 0..N-1)
FieldOrigin	fieldOrigin (int fieldIdx) const
	Get field's origin (value from an enumeration)
int	fieldOriginIndex (int fieldIdx) const
	Get field's origin index (its meaning is specific to each type of origin)
int	indexFromName (const QString &name) const
	Look up field's index from name. Returns -1 on error.
QList< QgsField >	toList () const
	Utility function to return a list of QgsField instances.

Protected Attributes
QVector< Field >	mFields
	internal storage of the container
QHash< QString, int >	mNameToIndex
	map for quick resolution of name to index

Detailed Description

Container of fields for a vector layer.

In addition to storing a list of QgsField instances, it also:

• allows quick lookups of field names to index in the list
• keeps track of where the field definition comes from (vector data provider, joined layer or newly added from an editing operation)

Definition at line 162 of file qgsfield.h.

Member Typedef Documentation

typedef struct QgsFields::Field QgsFields::Field

Member Enumeration Documentation

enum QgsFields::FieldOrigin

Enumerator:

OriginUnknown	it has not been specified where the field comes from
OriginProvider	field comes from the underlying data provider of the vector layer (originIndex = index in provider's fields)
OriginJoin	field comes from a joined layer (originIndex / 1000 = index of the join, originIndex % 1000 = index within the join)
OriginEdit	field has been temporarily added in editing mode (originIndex = index in the list of added attributes)

Definition at line 166 of file qgsfield.h.

Member Function Documentation

bool QgsFields::append	(	const QgsField &	field,
		FieldOrigin	origin = OriginProvider,
		int	originIndex = -1
	)

Append a field. The field must have unique name, otherwise it is rejected (returns false)

Definition at line 137 of file qgsfield.cpp.

References mFields, mNameToIndex, QgsField::name(), and OriginProvider.

Referenced by QgsOverlayAnalyzer::combineFieldLists(), QgsGeometryAnalyzer::convexHull(), QgsPointSample::createRandomPoints(), QgsTransectSample::createSample(), extend(), QgsGeometryAnalyzer::extent(), QgsVectorLayerJoinBuffer::updateFields(), and QgsVectorLayerEditBuffer::updateFields().

const QgsField& QgsFields::at ( int  i ) const

inline

Get field at particular index (must be in range 0..N-1)

Definition at line 209 of file qgsfield.h.

Referenced by extend(), QgsFeature::fieldNameIndex(), QgsRelation::getRelatedFeaturesRequest(), QgsDataDefinedButton::init(), QgsRelationEditorWidget::on_mUnlinkFeatureButton_clicked(), QgsPalLayerSettings::readDataDefinedProperty(), and QgsProjectFileTransform::transform0110to1000().

void QgsFields::clear

(

)

Remove all fields.

Definition at line 131 of file qgsfield.cpp.

References mFields, and mNameToIndex.

int QgsFields::count ( ) const

inline

Return number of items.

Definition at line 196 of file qgsfield.h.

Referenced by QgsAttributeDialog::accept(), QgsVectorLayerEditBuffer::addAttribute(), QgsVectorLayerEditBuffer::addFeature(), QgsVectorLayerFeatureIterator::addJoinedAttributes(), QgsOfflineEditing::applyFeaturesAdded(), QgsVectorLayer::attributeDisplayName(), QgsVectorDataProvider::attributeIndexes(), QgsVectorLayerEditBuffer::changeAttributeValue(), QgsVectorLayer::checkedState(), QgsOverlayAnalyzer::combineFieldLists(), QgsVectorLayerEditBuffer::commitChanges(), QgsOfflineEditing::copyVectorLayer(), QgsFormAnnotationItem::createDesignerWidget(), QgsVectorFileWriter::createFeature(), QgsVectorLayerEditBuffer::deleteAttribute(), QgsVectorLayer::editType(), QgsAttributeAction::expandAction(), extend(), QgsVectorLayer::fieldEditable(), QgsVectorDataProvider::fieldNameIndex(), QgsFeature::fieldNameIndex(), QgsVectorLayer::fieldNameIndex(), QgsVectorDataProvider::fieldNameMap(), QgsVectorDataProvider::fillMinMaxCache(), QgsComposerAttributeTable::getHeaderLabels(), QgsZonalStatistics::getUniqueFieldName(), QgsVectorLayerImport::importLayer(), QgsDataDefinedButton::init(), QgsAttributeDialog::init(), QgsComposerAttributeTable::initializeAliasMap(), QgsLabel::labelField(), QgsVectorLayer::labelOnTop(), QgsAttributeTableModel::loadAttributes(), QgsExpressionBuilderWidget::loadFieldNames(), QgsVectorLayer::pendingAllAttributesList(), QgsVectorLayer::pendingPkAttributesList(), QgsSearchQueryBuilder::populateFields(), QgsQueryBuilder::populateFields(), QgsExpression::NodeColumnRef::prepare(), QgsFeature::QgsFeature(), QgsVectorFileWriter::QgsVectorFileWriter(), QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator(), QgsVectorLayerUndoCommandAddAttribute::QgsVectorLayerUndoCommandAddAttribute(), QgsVectorLayer::range(), QgsLabel::readLabelField(), QgsVectorLayer::setCheckedState(), QgsVectorLayer::setDisplayField(), QgsVectorLayer::setEditType(), QgsVectorLayer::setFieldEditable(), QgsFeature::setFields(), QgsVectorLayer::setLabelOnTop(), QgsFeatureRequest::setSubsetOfAttributes(), QgsProjectFileTransform::transform0110to1000(), QgsVectorLayerJoinBuffer::updateFields(), QgsVectorLayer::valueMap(), and QgsVectorLayer::valueRelation().

bool QgsFields::exists ( int  i ) const

inline

Return if a field index is valid.

Parameters

i	Index of the field which needs to be checked

Returns

True if the field exists

Definition at line 202 of file qgsfield.h.

Referenced by QgsVectorLayerFeatureIterator::prepareJoins().

void QgsFields::extend

(

const QgsFields &

other

)

Extend with fields from another QgsFields container.

Definition at line 156 of file qgsfield.cpp.

References append(), at(), count(), fieldOrigin(), and fieldOriginIndex().

const QgsField& QgsFields::field ( int  fieldIdx ) const

inline

Get field at particular index (must be in range 0..N-1)

Definition at line 211 of file qgsfield.h.

Referenced by QgsTransectSample::createSample(), remove(), and QgsVectorLayerJoinBuffer::updateFields().

const QgsField& QgsFields::field ( const QString &  name ) const

inline

Get field at particular index (must be in range 0..N-1)

Definition at line 213 of file qgsfield.h.

FieldOrigin QgsFields::fieldOrigin ( int  fieldIdx ) const

inline

Get field's origin (value from an enumeration)

Definition at line 216 of file qgsfield.h.

Referenced by QgsOfflineEditing::applyFeaturesAdded(), QgsVectorLayerEditBuffer::changeAttributeValue(), QgsVectorLayerEditBuffer::deleteAttribute(), extend(), QgsVectorLayer::fieldEditable(), QgsVectorLayerJoinBuffer::joinForFieldIndex(), QgsVectorLayer::maximumValue(), QgsVectorLayer::minimumValue(), QgsVectorLayer::pendingPkAttributesList(), QgsVectorLayerFeatureIterator::prepareJoins(), QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator(), QgsVectorLayerUndoCommandAddAttribute::QgsVectorLayerUndoCommandAddAttribute(), QgsVectorLayerUndoCommandDeleteAttribute::QgsVectorLayerUndoCommandDeleteAttribute(), and QgsVectorLayer::uniqueValues().

int QgsFields::fieldOriginIndex ( int  fieldIdx ) const

inline

Get field's origin index (its meaning is specific to each type of origin)

Definition at line 218 of file qgsfield.h.

Referenced by QgsOfflineEditing::applyFeaturesAdded(), QgsVectorLayerEditBuffer::deleteAttribute(), extend(), QgsVectorLayerJoinBuffer::joinForFieldIndex(), QgsVectorLayer::pendingPkAttributesList(), QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator(), QgsVectorLayerUndoCommandDeleteAttribute::QgsVectorLayerUndoCommandDeleteAttribute(), and QgsVectorLayerUndoCommandAddAttribute::undo().

int QgsFields::indexFromName ( const QString &  name ) const

inline

Look up field's index from name. Returns -1 on error.

Definition at line 221 of file qgsfield.h.

Referenced by QgsVectorLayerJoinBuffer::cacheJoinLayer(), QgsPalLayerSettings::dataDefinedValue(), QgsRelation::getRelatedFeaturesRequest(), QgsRelationEditorWidget::on_mAddFeatureButton_clicked(), and QgsVectorLayerFeatureIterator::prepareJoins().

bool QgsFields::isEmpty ( ) const

inline

Check whether the container is empty.

Definition at line 194 of file qgsfield.h.

Referenced by QgsAttributeDialog::init(), and QgsExpressionBuilderWidget::loadFieldNames().

const QgsField& QgsFields::operator[] ( int  i ) const

inline

Get field at particular index (must be in range 0..N-1)

Definition at line 205 of file qgsfield.h.

QgsField& QgsFields::operator[] ( int  i )

inline

Get field at particular index (must be in range 0..N-1)

Definition at line 207 of file qgsfield.h.

void QgsFields::remove

(

int

fieldIdx

)

Remove a field with the given index.

Definition at line 150 of file qgsfield.cpp.

References field(), mFields, mNameToIndex, and QgsField::name().

Referenced by QgsVectorLayerEditBuffer::updateFields().

int QgsFields::size ( ) const

inline

Return number of items.

Definition at line 198 of file qgsfield.h.

Referenced by QgsVectorLayerEditBuffer::commitChanges(), QgsGml::QgsGml(), QgsVectorFileWriter::QgsVectorFileWriter(), QgsPalLayerSettings::readDataDefinedProperty(), and QgsVectorLayer::setDisplayField().

QList< QgsField > QgsFields::toList

(

)

const

Utility function to return a list of QgsField instances.

Definition at line 164 of file qgsfield.cpp.

References mFields.

Referenced by QgsDualView::columnBoxInit(), QgsGeometryAnalyzer::eventLayer(), and QgsRelationAddDlg::loadLayerAttributes().

Member Data Documentation

QVector<Field> QgsFields::mFields

protected

internal storage of the container

Definition at line 228 of file qgsfield.h.

Referenced by append(), clear(), remove(), and toList().

QHash<QString, int> QgsFields::mNameToIndex

protected

map for quick resolution of name to index

Definition at line 231 of file qgsfield.h.

Referenced by append(), clear(), and remove().

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

• /tmp/buildd/qgis-2.2.0+wheezy1/src/core/qgsfield.h
• /tmp/buildd/qgis-2.2.0+wheezy1/src/core/qgsfield.cpp