A convenience class for exporting vector layers to a destination data provider. More...

#include <qgsvectorlayerexporter.h>

Inheritance diagram for QgsVectorLayerExporter:

Public Types
enum	ExportError { NoError = 0, ErrCreateDataSource, ErrCreateLayer, ErrAttributeTypeUnsupported, ErrAttributeCreationFailed, ErrProjection, ErrFeatureWriteFailed, ErrInvalidLayer, ErrInvalidProvider, ErrProviderUnsupportedFeature, ErrConnectionFailed, ErrUserCanceled }
	Error codes. More...

Public Types inherited from QgsFeatureSink
enum	Flag { FastInsert = 1 << 1 }
	Flags controlling how features are added to a sink. More...

enum	SinkFlag { RegeneratePrimaryKey = 1 << 1 }
	Flags that can be set on a QgsFeatureSink. More...

Public Member Functions
	QgsVectorLayerExporter (const QString &uri, const QString &provider, const QgsFields &fields, QgsWkbTypes::Type geometryType, const QgsCoordinateReferenceSystem &crs, bool overwrite=false, const QMap< QString, QVariant > &options=QMap< QString, QVariant >(), QgsFeatureSink::SinkFlags sinkFlags=nullptr)
	Constructor for QgsVectorLayerExporter. More...

	QgsVectorLayerExporter (const QgsVectorLayerExporter &rh)=delete
	QgsVectorLayerExporter cannot be copied. More...

	~QgsVectorLayerExporter () override
	Finalizes the export and closes the new created layer. More...

bool	addFeature (QgsFeature &feature, QgsFeatureSink::Flags flags=nullptr) override
	Adds a single feature to the sink. More...

bool	addFeatures (QgsFeatureList &features, QgsFeatureSink::Flags flags=nullptr) override
	Adds a list of features to the sink. More...

ExportError	errorCode () const
	Returns any encountered error code, or false if no error was encountered. More...

int	errorCount () const
	Returns the number of error messages encountered during the export. More...

QString	errorMessage () const
	Returns any error message encountered during the export. More...

bool	flushBuffer () override
	Flushes any internal buffer which may exist in the sink, causing any buffered features to be added to the sink's destination. More...

QgsVectorLayerExporter &	operator= (const QgsVectorLayerExporter &rh)=delete
	QgsVectorLayerExporter cannot be copied. More...

Public Member Functions inherited from QgsFeatureSink
virtual	~QgsFeatureSink ()=default

virtual bool	addFeatures (QgsFeatureIterator &iterator, QgsFeatureSink::Flags flags=nullptr)
	Adds all features from the specified iterator to the sink. More...

Static Public Member Functions
static ExportError	exportLayer (QgsVectorLayer layer, const QString &uri, const QString &providerKey, const QgsCoordinateReferenceSystem &destCRS, bool onlySelected=false, QString errorMessage=nullptr, const QMap< QString, QVariant > &options=QMap< QString, QVariant >(), QgsFeedback *feedback=nullptr)
	Writes the contents of vector layer to a different datasource. More...

Detailed Description

A convenience class for exporting vector layers to a destination data provider.

QgsVectorLayerExporter can be used in two ways:

Using a static call to QgsVectorLayerExporter::exportLayer(...) which exports the entire layer to the destination provider.
Create an instance of the class and issue calls to addFeature(...)

Since: QGIS 3.0

Definition at line 47 of file qgsvectorlayerexporter.h.

Member Enumeration Documentation

enum QgsVectorLayerExporter::ExportError

Error codes.

Enumerator
NoError	No errors were encountered.
ErrCreateDataSource	Could not create the destination data source.
ErrCreateLayer	Could not create destination layer.
ErrAttributeTypeUnsupported	Source layer has an attribute type which could not be handled by destination.
ErrAttributeCreationFailed	Destination provider was unable to create an attribute.
ErrProjection	An error occurred while reprojecting features to destination CRS.
ErrFeatureWriteFailed	An error occurred while writing a feature to the destination.
ErrInvalidLayer	Could not access newly created destination layer.
ErrInvalidProvider	Could not find a matching provider key.
ErrProviderUnsupportedFeature	Provider does not support creation of empty layers.
ErrConnectionFailed	Could not connect to destination.
ErrUserCanceled	User canceled the export.

Definition at line 52 of file qgsvectorlayerexporter.h.

Constructor & Destructor Documentation

QgsVectorLayerExporter::QgsVectorLayerExporter	(	const QString &	uri,
		const QString &	provider,
		const QgsFields &	fields,
		QgsWkbTypes::Type	geometryType,
		const QgsCoordinateReferenceSystem &	crs,
		bool	overwrite = `false`,
		const QMap< QString, QVariant > &	options = `QMap<QString, QVariant>()`,
		QgsFeatureSink::SinkFlags	sinkFlags = `nullptr`
	)

Constructor for QgsVectorLayerExporter.

Parameters

uri	URI for destination data source
provider	string key for destination data provider
fields	fields to include in created layer
geometryType	destination geometry type
crs	desired CRS, or an invalid (default constructed) CRS if not available
overwrite	set to true to overwrite any existing data source
options	optional provider dataset options
sinkFlags	for how to add features

Definition at line 48 of file qgsvectorlayerexporter.cpp.

QgsVectorLayerExporter::QgsVectorLayerExporter ( const QgsVectorLayerExporter & rh )

delete

QgsVectorLayerExporter cannot be copied.

QgsVectorLayerExporter::~QgsVectorLayerExporter ( )

override

Finalizes the export and closes the new created layer.

Definition at line 144 of file qgsvectorlayerexporter.cpp.

Member Function Documentation

bool QgsVectorLayerExporter::addFeature	(	QgsFeature &	feature,
		QgsFeatureSink::Flags	flags = `nullptr`
	)

overridevirtual

Adds a single feature to the sink.

Feature addition behavior is controlled by the specified flags.

See also: addFeatures()

Returns: true in case of success and false in case of failure

Reimplemented from QgsFeatureSink.

Definition at line 171 of file qgsvectorlayerexporter.cpp.

bool QgsVectorLayerExporter::addFeatures	(	QgsFeatureList &	features,
		QgsFeatureSink::Flags	flags = `nullptr`
	)

overridevirtual

Adds a list of features to the sink.

Feature addition behavior is controlled by the specified flags.

See also: addFeature()

Returns: true in case of success and false in case of failure

Implements QgsFeatureSink.

Definition at line 160 of file qgsvectorlayerexporter.cpp.

QgsVectorLayerExporter::ExportError QgsVectorLayerExporter::errorCode ( ) const

Returns any encountered error code, or false if no error was encountered.

See also: errorMessage(); errorCount()

Definition at line 150 of file qgsvectorlayerexporter.cpp.

int QgsVectorLayerExporter::errorCount ( ) const

inline

Returns the number of error messages encountered during the export.

See also: errorMessage(); errorCode()

Definition at line 136 of file qgsvectorlayerexporter.h.

QString QgsVectorLayerExporter::errorMessage ( ) const

Returns any error message encountered during the export.

See also: errorCount(); errorCode()

Definition at line 155 of file qgsvectorlayerexporter.cpp.

QgsVectorLayerExporter::ExportError QgsVectorLayerExporter::exportLayer	(	QgsVectorLayer *	layer,
		const QString &	uri,
		const QString &	providerKey,
		const QgsCoordinateReferenceSystem &	destCRS,
		bool	onlySelected = `false`,
		QString *	errorMessage = `nullptr`,
		const QMap< QString, QVariant > &	options = `QMap<QString, QVariant>()`,
		QgsFeedback *	feedback = `nullptr`
	)

static

Writes the contents of vector layer to a different datasource.

Parameters

layer	source layer
uri	URI for destination data source
providerKey	string key for destination data provider
destCRS	destination CRS, or an invalid (default constructed) CRS if not available
onlySelected	set to true to export only selected features
errorMessage	if non-null, will be set to any error messages
options	optional provider dataset options
feedback	optional feedback object to show progress and cancellation of export