QGIS API Documentation
2.14.0-Essen
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Abstract base class for spatial data provider implementations. More...
#include <qgsdataprovider.h>
Public Types | |
enum | DataCapability { NoDataCapabilities = 0, File = 1, Dir = 1 << 1, Database = 1 << 2, Net = 1 << 3 } |
Signals | |
void | dataChanged () |
This is emitted whenever an asynchronous operation has finished and the data should be redrawn. More... | |
void | dataChanged (int changed) |
This is emitted whenever data or metadata (e.g. More... | |
void | fullExtentCalculated () |
This is emitted whenever the worker thread has fully calculated the PostGIS extents for this layer, and its event has been received by this provider. More... | |
Public Member Functions | |
QgsDataProvider (QString const &uri="") | |
virtual | ~QgsDataProvider () |
We need this so the subclass destructors get called. More... | |
virtual QgsCoordinateReferenceSystem | crs ()=0 |
Get the QgsCoordinateReferenceSystem for this layer. More... | |
virtual QString | dataSourceUri (bool expandAuthConfig=false) const |
Get the data source specification. More... | |
virtual QDateTime | dataTimestamp () const |
Current time stamp of data source. More... | |
virtual QString | description () const =0 |
Return description. More... | |
virtual QgsError | error () const |
Get current status error. More... | |
virtual QgsRectangle | extent ()=0 |
Get the extent of the layer. More... | |
virtual QString | fileRasterFilters () const |
Return raster file filter string. More... | |
virtual QString | fileVectorFilters () const |
Return vector file filter string. More... | |
virtual bool | isValid ()=0 |
Returns true if this is a valid layer. More... | |
virtual QString | name () const =0 |
Return a provider name. More... | |
virtual void | reloadData () |
Reloads the data from the source. More... | |
virtual void | setDataSourceUri (const QString &uri) |
Set the data source specification. More... | |
virtual void | setLayerOrder (const QStringList &layers) |
Reorder the list of layer names to be rendered by this provider (in order from bottom to top) More... | |
virtual void | setSubLayerVisibility (const QString &name, bool vis) |
Set the visibility of the given sublayer name. More... | |
virtual bool | setSubsetString (const QString &subset, bool updateFeatureCount=true) |
Set the subset string used to create a subset of features in the layer. More... | |
virtual uint | subLayerCount () const |
return the number of layers for the current data source More... | |
virtual QStringList | subLayers () const |
Sub-layers handled by this provider, in order from bottom to top. More... | |
virtual QStringList | subLayerStyles () const |
Sub-layer styles for each sub-layer handled by this provider, in order from bottom to top. More... | |
virtual QString | subsetString () |
Returns the subset definition string (typically sql) currently in use by the layer and used by the provider to limit the feature set. More... | |
virtual bool | supportsSubsetString () |
Provider supports setting of subset strings. More... | |
virtual QDateTime | timestamp () const |
Time stamp of data source in the moment when data/metadata were loaded by provider. More... | |
virtual void | updateExtents () |
Update the extents of the layer. More... | |
Public Member Functions inherited from QObject | |
QObject (QObject *parent) | |
QObject (QObject *parent, const char *name) | |
virtual | ~QObject () |
bool | blockSignals (bool block) |
QObject * | child (const char *objName, const char *inheritsClass, bool recursiveSearch) const |
const QObjectList & | children () const |
const char * | className () const |
bool | connect (const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const |
void | deleteLater () |
void | destroyed (QObject *obj) |
bool | disconnect (const QObject *receiver, const char *method) |
bool | disconnect (const char *signal, const QObject *receiver, const char *method) |
void | dumpObjectInfo () |
void | dumpObjectTree () |
QList< QByteArray > | dynamicPropertyNames () const |
virtual bool | event (QEvent *e) |
virtual bool | eventFilter (QObject *watched, QEvent *event) |
T | findChild (const QString &name) const |
QList< T > | findChildren (const QRegExp ®Exp) const |
QList< T > | findChildren (const QString &name) const |
bool | inherits (const char *className) const |
void | insertChild (QObject *object) |
void | installEventFilter (QObject *filterObj) |
bool | isA (const char *className) const |
bool | isWidgetType () const |
void | killTimer (int id) |
virtual const QMetaObject * | metaObject () const |
void | moveToThread (QThread *targetThread) |
const char * | name () const |
const char * | name (const char *defaultName) const |
QString | objectName () const |
QObject * | parent () const |
QVariant | property (const char *name) const |
void | removeChild (QObject *object) |
void | removeEventFilter (QObject *obj) |
void | setName (const char *name) |
void | setObjectName (const QString &name) |
void | setParent (QObject *parent) |
bool | setProperty (const char *name, const QVariant &value) |
bool | signalsBlocked () const |
int | startTimer (int interval) |
QThread * | thread () const |
Protected Member Functions | |
void | appendError (const QgsErrorMessage &theMessage) |
Add error message. More... | |
void | setError (const QgsError &theError) |
Set error message. More... | |
Protected Member Functions inherited from QObject | |
bool | checkConnectArgs (const char *signal, const QObject *object, const char *method) |
virtual void | childEvent (QChildEvent *event) |
virtual void | connectNotify (const char *signal) |
virtual void | customEvent (QEvent *event) |
virtual void | disconnectNotify (const char *signal) |
int | receivers (const char *signal) const |
QObject * | sender () const |
int | senderSignalIndex () const |
virtual void | timerEvent (QTimerEvent *event) |
Protected Attributes | |
QgsError | mError |
Error. More... | |
QDateTime | mTimestamp |
Timestamp of data in the moment when the data were loaded by provider. More... | |
Additional Inherited Members | |
Static Public Member Functions inherited from QObject | |
bool | connect (const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type) |
bool | connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type) |
bool | disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *method) |
bool | disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method) |
QString | tr (const char *sourceText, const char *disambiguation, int n) |
QString | trUtf8 (const char *sourceText, const char *disambiguation, int n) |
Static Protected Member Functions inherited from QObject | |
QByteArray | normalizeSignalSlot (const char *signalSlot) |
Properties inherited from QObject | |
objectName | |
Abstract base class for spatial data provider implementations.
This object needs to inherit from QObject to enable event processing in the Postgres/PostGIS provider (QgsPostgresProvider). It is called here so that this vtable and the vtable for QgsPostgresProvider don't get misaligned - the QgsVectorLayer class factory (which refers to generic QgsVectorDataProvider's) depends on it.
Definition at line 47 of file qgsdataprovider.h.
Enumerator | |
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NoDataCapabilities | |
File | |
Dir | |
Database | |
Net |
Definition at line 55 of file qgsdataprovider.h.
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inline |
Definition at line 64 of file qgsdataprovider.h.
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inlinevirtual |
We need this so the subclass destructors get called.
Definition at line 71 of file qgsdataprovider.h.
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inlineprotected |
Add error message.
Definition at line 343 of file qgsdataprovider.h.
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pure virtual |
Get the QgsCoordinateReferenceSystem for this layer.
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signal |
This is emitted whenever an asynchronous operation has finished and the data should be redrawn.
When emitted from a QgsVectorDataProvider, any cached information such as feature ids should be invalidated.
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signal |
This is emitted whenever data or metadata (e.g.
color table, extent) has changed
changed | binary combination of changes |
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inlinevirtual |
Get the data source specification.
This may be a path or database connection string
expandAuthConfig | Whether to expand any assigned authentication configuration |
Definition at line 101 of file qgsdataprovider.h.
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inlinevirtual |
Current time stamp of data source.
Reimplemented in QgsRasterDataProvider.
Definition at line 301 of file qgsdataprovider.h.
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pure virtual |
Return description.
Return a terse string describing what the provider is.
Instead of being pure virtual, might be better to generalize this behavior and presume that none of the sub-classes are going to do anything strange with regards to their name or description?
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inlinevirtual |
Get current status error.
This error describes some principal problem for which provider cannot work and thus is not valid. It is not last error after accessing data by block(), identify() etc.
Definition at line 307 of file qgsdataprovider.h.
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pure virtual |
Get the extent of the layer.
Implemented in QgsRasterDataProvider.
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inlinevirtual |
Return raster file filter string.
Returns a string suitable for a QFileDialog of raster file formats supported by the data provider. Naturally this will be an empty string for those data providers that do not deal with plain files, such as databases and servers.
Definition at line 287 of file qgsdataprovider.h.
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inlinevirtual |
Return vector file filter string.
Returns a string suitable for a QFileDialog of vector file formats supported by the data provider. Naturally this will be an empty string for those data providers that do not deal with plain files, such as databases and servers.
Definition at line 272 of file qgsdataprovider.h.
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signal |
This is emitted whenever the worker thread has fully calculated the PostGIS extents for this layer, and its event has been received by this provider.
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pure virtual |
Returns true if this is a valid layer.
It is up to individual providers to determine what constitutes a valid layer
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pure virtual |
Return a provider name.
Essentially just returns the provider key. Should be used to build file dialogs so that providers can be shown with their supported types. Thus if more than one provider supports a given format, the user is able to select a specific provider to open that file.
Instead of being pure virtual, might be better to generalize this behavior and presume that none of the sub-classes are going to do anything strange with regards to their name or description?
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inlinevirtual |
Reloads the data from the source.
Needs to be implemented by providers with data caches to synchronize with changes in the data source
Definition at line 295 of file qgsdataprovider.h.
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inlinevirtual |
Set the data source specification.
This may be a path or database connection string
uri | source specification |
Definition at line 87 of file qgsdataprovider.h.
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inlineprotected |
Set error message.
Definition at line 346 of file qgsdataprovider.h.
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inlinevirtual |
Reorder the list of layer names to be rendered by this provider (in order from bottom to top)
Definition at line 207 of file qgsdataprovider.h.
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inlinevirtual |
Set the visibility of the given sublayer name.
Definition at line 221 of file qgsdataprovider.h.
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inlinevirtual |
Set the subset string used to create a subset of features in the layer.
This may be a sql where clause or any other string that can be used by the data provider to create a subset. Must be implemented in the dataprovider.
Definition at line 144 of file qgsdataprovider.h.
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inlinevirtual |
return the number of layers for the current data source
Definition at line 196 of file qgsdataprovider.h.
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inlinevirtual |
Sub-layers handled by this provider, in order from bottom to top.
Sub-layers are used when the provider's source can combine layers it knows about in some way before it hands them off to the provider.
Reimplemented in QgsRasterDataProvider.
Definition at line 174 of file qgsdataprovider.h.
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inlinevirtual |
Sub-layer styles for each sub-layer handled by this provider, in order from bottom to top.
Sub-layer styles are used to abstract the way the provider's source can symbolise layers in some way at the server, before it serves them to the provider.
Definition at line 187 of file qgsdataprovider.h.
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inlinevirtual |
Returns the subset definition string (typically sql) currently in use by the layer and used by the provider to limit the feature set.
Must be overridden in the dataprovider, otherwise returns a null QString.
Definition at line 162 of file qgsdataprovider.h.
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inlinevirtual |
Provider supports setting of subset strings.
Definition at line 154 of file qgsdataprovider.h.
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inlinevirtual |
Time stamp of data source in the moment when data/metadata were loaded by provider.
Reimplemented in QgsRasterDataProvider.
Definition at line 298 of file qgsdataprovider.h.
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inlinevirtual |
Update the extents of the layer.
Not implemented by default
Definition at line 132 of file qgsdataprovider.h.
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protected |
Error.
Definition at line 340 of file qgsdataprovider.h.
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protected |
Timestamp of data in the moment when the data were loaded by provider.
Definition at line 337 of file qgsdataprovider.h.