QgsProjectBadLayerHandler class

Interface for classes that handle missing layer files when reading project file.

Contents

Public functions

void handleBadLayers(const QList<QDomNode>& layers) virtual
This method will be called whenever the project tries to load layers which cannot be accessed.

Protected types

enum DataType { IS_VECTOR, IS_RASTER, IS_BOGUS }
file data representation
enum ProviderType { IS_FILE, IS_DATABASE, IS_URL, IS_Unknown }
the flavors for data storage

Protected functions

auto dataSource(const QDomNode& layerNode) -> QString
Returns the data source for the given layer.
auto dataType(const QDomNode& layerNode) -> DataType
Returns data type associated with the given QgsProject file Dom node.
auto providerType(const QDomNode& layerNode) -> ProviderType
Returns the physical storage type associated with the given layer.
void setDataSource(QDomNode& layerNode, const QString& dataSource)
Set the datasource element to the new value.

Enum documentation

enum QgsProjectBadLayerHandler::DataType protected

file data representation

Enumerators
IS_VECTOR

Vector data.
IS_RASTER

Raster data.
IS_BOGUS

Bogus data.

enum QgsProjectBadLayerHandler::ProviderType protected

the flavors for data storage

Enumerators
IS_FILE

Saved in a file.
IS_DATABASE

Saved in a database.
IS_URL

Retrieved from a URL.
IS_Unknown

Unknown type.

Function documentation

void QgsProjectBadLayerHandler::handleBadLayers(const QList<QDomNode>& layers) virtual

This method will be called whenever the project tries to load layers which cannot be accessed.

It should inform the user about this and if possible offer to fix the unavailable layers by setting a valid datasource, e.g. by showing a file dialog.

The default implementation will dismiss all bad layers and write information to the log.

QString QgsProjectBadLayerHandler::dataSource(const QDomNode& layerNode) protected

Returns the data source for the given layer.

The QDomNode is a QgsProject Dom node corresponding to a map layer state.

Essentially dumps datasource tag.

DataType QgsProjectBadLayerHandler::dataType(const QDomNode& layerNode) protected

Returns data type associated with the given QgsProject file Dom node.

The Dom node should represent the state associated with a specific layer.

ProviderType QgsProjectBadLayerHandler::providerType(const QDomNode& layerNode) protected

Returns the physical storage type associated with the given layer.

The QDomNode is a QgsProject Dom node corresponding to a map layer state.

If the provider tag is "ogr", then it's a file type.

However, if the layer is a raster, then there won't be a provider tag. It will always have an associated file.

If the layer doesn't fall into either of the previous two categories, then it's either a database or URL. If the datasource tag has "url=", then it's URL based and if it has "dbname=">, then the layer data is in a database.

void QgsProjectBadLayerHandler::setDataSource(QDomNode& layerNode, const QString& dataSource) protected

Set the datasource element to the new value.