Reads and writes project states. More...

#include <qgsproject.h>

Classes
struct	Imp

Signals
void	readProject (const QDomDocument &)
	emitted when project is being read
void	writeProject (QDomDocument &)
	emitted when project is being written
void	readMapLayer (QgsMapLayer *mapLayer, const QDomElement &layerNode)
	Emitted, after the basic initialisation of a layer from the project file is done.
void	writeMapLayer (QgsMapLayer *mapLayer, QDomElement &layerElem, QDomDocument &doc)
	Emitted, when a layer is being saved.
void	projectSaved ()
	emitted when the project file has been written and closed
void	oldProjectVersionWarning (QString)
	emitted when an old project file is read.
void	layerLoaded (int i, int n)
	emitted when a layer from a projects was read
void	loadingLayer (QString)
void	snapSettingsChanged ()

Public Member Functions
	~QgsProject ()
void	clear ()
	Clear the project.
bool	read (QDomNode &layerNode)
	read the layer described in the associated Dom node
void	clearProperties ()
	syntactic sugar for property lists
bool	removeEntry (const QString &scope, const QString &key)
	remove the given key
QStringList	entryList (const QString &scope, const QString &key) const
	return keys with values – do not return keys that contain other keys
QStringList	subkeyList (const QString &scope, const QString &key) const
	return keys with keys – do not return keys that contain only values
void	dumpProperties () const
	dump out current project properties to stderr
QString	writePath (QString filename, QString relativeBasePath=QString::null) const
	prepare a filename to save it to the project file
QString	readPath (QString filename) const
	turn filename read from the project file to an absolute path
QString	error () const
	Return error message from previous read/write.
void	setBadLayerHandler (QgsProjectBadLayerHandler *handler)
	Change handler for missing layers.
QString	layerIsEmbedded (const QString &id) const
	Returns project file path if layer is embedded from other project file.
bool	createEmbeddedLayer (const QString &layerId, const QString &projectFilePath, QList< QDomNode > &brokenNodes, QList< QPair< QgsVectorLayer *, QDomElement > > &vectorLayerList, bool saveFlag=true)
	Creates a maplayer instance defined in an arbitrary project file.
QgsLayerTreeGroup *	createEmbeddedGroup (const QString &groupName, const QString &projectFilePath)
	Create layer group instance defined in an arbitrary project file.
void	setSnapSettingsForLayer (const QString &layerId, bool enabled, QgsSnapper::SnappingType type, QgsTolerance::UnitType unit, double tolerance, bool avoidIntersection)
	Convenience function to set snap settings per layer.
bool	snapSettingsForLayer (const QString &layerId, bool &enabled, QgsSnapper::SnappingType &type, QgsTolerance::UnitType &units, double &tolerance, bool &avoidIntersection) const
	Convenience function to query snap settings of a layer.
void	setTopologicalEditing (bool enabled)
	Convenience function to set topological editing.
bool	topologicalEditing () const
	Convenience function to query topological editing status.
QString	homePath () const
	Return project's home path.
QgsRelationManager *	relationManager () const
QgsLayerTreeGroup *	layerTreeRoot () const
	Return pointer to the root (invisible) node of the project's layer tree.
QgsLayerTreeRegistryBridge *	layerTreeRegistryBridge () const
	Return pointer to the helper class that synchronizes map layer registry with layer tree.

void	title (const QString &title)
	Every project has an associated title string.
void	setTitle (const QString &title)
	Set project title.
const QString &	title () const
	returns title

bool	isDirty () const
	the dirty flag is true if the project has been modified since the last write()
void	dirty (bool b)
void	setDirty (bool b)
	Set project as dirty (modified).

void	setFileName (const QString &name)
	Every project has an associated file that contains its XML.
QString	fileName () const
	returns file name

bool	read (const QFileInfo &file)
	read project file
bool	read ()
	presuming that the caller has already reset the map canvas, map registry, and legend

bool	write (const QFileInfo &file)
	write project file
bool	write ()

bool	writeEntry (const QString &scope, const QString &key, bool value)
bool	writeEntry (const QString &scope, const QString &key, double value)
bool	writeEntry (const QString &scope, const QString &key, int value)
bool	writeEntry (const QString &scope, const QString &key, const QString &value)
bool	writeEntry (const QString &scope, const QString &key, const QStringList &value)

QStringList	readListEntry (const QString &scope, const QString &key, QStringList def=QStringList(), bool *ok=0) const
	key value accessors
QString	readEntry (const QString &scope, const QString &key, const QString &def=QString::null, bool *ok=0) const
int	readNumEntry (const QString &scope, const QString &key, int def=0, bool *ok=0) const
double	readDoubleEntry (const QString &scope, const QString &key, double def=0, bool *ok=0) const
bool	readBoolEntry (const QString &scope, const QString &key, bool def=false, bool *ok=0) const

Static Public Member Functions
static QgsProject *	instance ()
	access to canonical QgsProject instance

Protected Member Functions
void	setError (QString errorMessage)
	Set error message from read/write operation.
void	clearError ()
	Clear error message.
bool	addLayer (const QDomElement &layerElem, QList< QDomNode > &brokenNodes, QList< QPair< QgsVectorLayer *, QDomElement > > &vectorLayerList)
void	initializeEmbeddedSubtree (const QString &projectFilePath, QgsLayerTreeGroup *group)
void	loadEmbeddedNodes (QgsLayerTreeGroup *group)

Detailed Description

Reads and writes project states.

Note

Has two general kinds of state to make persistent. (I.e., to read and write.) First, Qgis proprietary information. Second plug-in information.

A singleton since there shall only be one active project at a time; and provides canonical location for plug-ins and main app to find/set properties.

Might want to consider moving from Singleton; i.e., allowing more than one project. Just as the GIMP can have simultaneous multiple images, perhaps qgis can one day have simultaneous multiple projects.

Constructor & Destructor Documentation

QgsProject::~QgsProject ( )

Todo:: XXX Should have semantics for saving project if dirty as last gasp?

Member Function Documentation

bool QgsProject::addLayer	(	const QDomElement &	layerElem,
		QList< QDomNode > &	brokenNodes,
		QList< QPair< QgsVectorLayer *, QDomElement > > &	vectorLayerList
	)

protected

Note: not available in python bindings

void QgsProject::clear ( )

Clear the project.

Note: added in 2.4

void QgsProject::clearError ( )

protected

Clear error message.

void QgsProject::clearProperties ( )

syntactic sugar for property lists

extra properties, typically added by plug-ins

This allows for extra properties to be associated with projects. Think of it as a registry bound to a project.

Properties are arbitrary values keyed by a name and associated with a scope. The scope would presumably refer to your plug-in. E.g., "openmodeller".

Note

E.g., open modeller might use:

"QgsProject::instance()->properties("openmodeller")["foo"].

Todo:: "properties" is, overall, a good name; but that might imply that the qgis specific state properites are different since they aren't accessible here. Actually, what if we make "qgis" yet another scope that stores its state in the properties list? E.g., QgsProject::instance()->properties()["qgis"]?

removes all project properties

QGIS 3: remove in favor of clear()

QgsLayerTreeGroup * QgsProject::createEmbeddedGroup	(	const QString &	groupName,
		const QString &	projectFilePath
	)

Create layer group instance defined in an arbitrary project file.

Note: : added in version 2.4

bool QgsProject::createEmbeddedLayer	(	const QString &	layerId,
		const QString &	projectFilePath,
		QList< QDomNode > &	brokenNodes,
		QList< QPair< QgsVectorLayer *, QDomElement > > &	vectorLayerList,
		bool	saveFlag = `true`
	)

Creates a maplayer instance defined in an arbitrary project file.

Caller takes ownership

Returns: the layer or 0 in case of error

void QgsProject::dirty ( bool b )

void QgsProject::dumpProperties ( ) const

dump out current project properties to stderr

Todo:: XXX Now slightly broken since re-factoring. Won't print out top-level key and redundantly prints sub-keys.

QStringList QgsProject::entryList	(	const QString &	scope,
		const QString &	key
	)		const

return keys with values – do not return keys that contain other keys

Note: equivalent to QSettings entryList()

QString QgsProject::error ( ) const

Return error message from previous read/write.

QString QgsProject::fileName ( ) const

returns file name

QString QgsProject::homePath ( ) const

Return project's home path.

Returns: home path of project (or QString::null if not set)

void QgsProject::initializeEmbeddedSubtree	(	const QString &	projectFilePath,
		QgsLayerTreeGroup *	group
	)

protected

Note: not available in python bindings

QgsProject * QgsProject::instance ( )

static

access to canonical QgsProject instance

bool QgsProject::isDirty ( ) const

the dirty flag is true if the project has been modified since the last write()

QString QgsProject::layerIsEmbedded ( const QString & id ) const

Returns project file path if layer is embedded from other project file.

Returns empty string if layer is not embedded

void QgsProject::layerLoaded	(	int	i,
		int	n
	)

signal

emitted when a layer from a projects was read

QgsLayerTreeRegistryBridge* QgsProject::layerTreeRegistryBridge ( ) const

inline

Return pointer to the helper class that synchronizes map layer registry with layer tree.

Note: added in 2.4

QgsLayerTreeGroup * QgsProject::layerTreeRoot ( ) const

Return pointer to the root (invisible) node of the project's layer tree.

Note: added in 2.4

void QgsProject::loadEmbeddedNodes ( QgsLayerTreeGroup * group )

protected

Note: not available in python bindings

void QgsProject::loadingLayer ( QString )

signal

void QgsProject::oldProjectVersionWarning ( QString )

signal

emitted when an old project file is read.

void QgsProject::projectSaved ( )

signal

emitted when the project file has been written and closed

bool QgsProject::read ( const QFileInfo & file )

read project file

Please note that most of the contents were copied from qgsproject.

Note: Any current plug-in state is erased; dirty set to false after successful invocation; file name argument implicitly sets file

Gets the extents
Creates maplayers
Registers maplayers

Note: it's presumed that the caller has already reset the map canvas, map registry, and legend

bool QgsProject::read ( )

presuming that the caller has already reset the map canvas, map registry, and legend

Shows a warning when an old project file is read.

bool QgsProject::read ( QDomNode & layerNode )

read the layer described in the associated Dom node

Parameters

layerNode represents a QgsProject Dom node that maps to a specific layer.

QgsProject raises an exception when one of the QgsProject::read() implementations fails. Since the read()s are invoked from qgisapp, then qgisapp handles the exception. It prompts the user for the new location of the data, if any. If there is a new location, the Dom node associated with the layer has its datasource tag corrected. Then that node is passed to this member function to be re-opened.

bool QgsProject::readBoolEntry	(	const QString &	scope,
		const QString &	key,
		bool	def = `false`,
		bool *	ok = `0`
	)		const

double QgsProject::readDoubleEntry	(	const QString &	scope,
		const QString &	key,
		double	def = `0`,
		bool *	ok = `0`
	)		const

QString QgsProject::readEntry	(	const QString &	scope,
		const QString &	key,
		const QString &	def = `QString::null`,
		bool *	ok = `0`
	)		const

QStringList QgsProject::readListEntry	(	const QString &	scope,
		const QString &	key,
		QStringList	def = `QStringList()`,
		bool *	ok = `0`
	)		const

key value accessors

keys would be the familiar QSettings-like '/' delimited entries, implying a hierarchy of keys and corresponding values

Note: The key string must include '/'s. E.g., "/foo" not "foo".

void QgsProject::readMapLayer	(	QgsMapLayer *	mapLayer,
		const QDomElement &	layerNode
	)

signal

Emitted, after the basic initialisation of a layer from the project file is done.

You can use this signal to read additional information from the project file.

Parameters

mapLayer	The map layer which is being initialized
layerNode	The layer node from the project file

int QgsProject::readNumEntry	(	const QString &	scope,
		const QString &	key,
		int	def = `0`,
		bool *	ok = `0`
	)		const

QString QgsProject::readPath ( QString filename ) const

turn filename read from the project file to an absolute path

void QgsProject::readProject ( const QDomDocument & )

signal

emitted when project is being read

QgsRelationManager * QgsProject::relationManager ( ) const

bool QgsProject::removeEntry	(	const QString &	scope,
		const QString &	key
	)

remove the given key

void QgsProject::setBadLayerHandler ( QgsProjectBadLayerHandler * handler )

Change handler for missing layers.

Deletes old handler and takes ownership of the new one.

void QgsProject::setDirty ( bool b )

Set project as dirty (modified).

Note: added in 2.4

void QgsProject::setError ( QString errorMessage )

protected

Set error message from read/write operation.

void QgsProject::setFileName ( const QString & name )

Every project has an associated file that contains its XML.

void QgsProject::setSnapSettingsForLayer	(	const QString &	layerId,
		bool	enabled,
		QgsSnapper::SnappingType	type,
		QgsTolerance::UnitType	unit,
		double	tolerance,
		bool	avoidIntersection
	)

Convenience function to set snap settings per layer.

void QgsProject::setTitle ( const QString & title )

Set project title.

Note: added in 2.4

void QgsProject::setTopologicalEditing ( bool enabled )

Convenience function to set topological editing.

void QgsProject::snapSettingsChanged ( )

signal

bool QgsProject::snapSettingsForLayer	(	const QString &	layerId,
		bool &	enabled,
		QgsSnapper::SnappingType &	type,
		QgsTolerance::UnitType &	units,
		double &	tolerance,
		bool &	avoidIntersection
	)		const

Convenience function to query snap settings of a layer.

QStringList QgsProject::subkeyList	(	const QString &	scope,
		const QString &	key
	)		const

return keys with keys – do not return keys that contain only values

Note: equivalent to QSettings subkeyList()

void QgsProject::title ( const QString & title )

Every project has an associated title string.

QGIS 3: remove in favor of setTitle(...)

QString const & QgsProject::title ( ) const

returns title

bool QgsProject::topologicalEditing ( ) const

Convenience function to query topological editing status.

bool QgsProject::write ( const QFileInfo & file )

write project file

XXX How to best get read access to Qgis state? Actually we can finagle that by searching for qgisapp in object hiearchy.

Note: file name argument implicitly sets file; dirty set to false after successful invocation

bool QgsProject::write ( )

bool QgsProject::writeEntry	(	const QString &	scope,
		const QString &	key,
		bool	value
	)

Note: available in python bindings as writeEntryBool

bool QgsProject::writeEntry	(	const QString &	scope,
		const QString &	key,
		double	value
	)

Note: available in python bindings as writeEntryDouble

bool QgsProject::writeEntry	(	const QString &	scope,
		const QString &	key,
		int	value
	)

bool QgsProject::writeEntry	(	const QString &	scope,
		const QString &	key,
		const QString &	value
	)

bool QgsProject::writeEntry	(	const QString &	scope,
		const QString &	key,
		const QStringList &	value
	)

void QgsProject::writeMapLayer	(	QgsMapLayer *	mapLayer,
		QDomElement &	layerElem,
		QDomDocument &	doc
	)

signal

Emitted, when a layer is being saved.

You can use this method to save additional information to the layer.

Parameters

mapLayer	The map layer which is being initialized
layerElem	The layer element from the project file
doc	The document

QString QgsProject::writePath	(	QString	filename,
		QString	relativeBasePath = `QString::null`
	)		const

prepare a filename to save it to the project file

void QgsProject::writeProject ( QDomDocument & )

signal

emitted when project is being written

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

/tmp/buildd/qgis-2.6.0+wheezy1/src/core/qgsproject.h
/tmp/buildd/qgis-2.6.0+wheezy1/src/core/qgsproject.cpp

Classes

Signals

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

QGIS 3: remove in favor of clear()

QGIS 3: remove in favor of setTitle(...)