Class: QgsProjectProperty

class qgis.core.QgsProjectProperty

Bases: sip.wrapper

An Abstract Base Class for QGIS project property hierarchys.

Each sub-class is either a QgsProjectPropertyKey or QgsProjectPropertyValue. QgsProjectPropertyKey can contain either QgsProjectPropertyKey or QgsProjectPropertyValues, thus describing an hierarchy. QgsProjectPropertyValues are always graph leaves.

Note

This class is used internally by QgsProject. It’s generally recommended that the methods in QgsProject are used to modify project properties rather than using these low-level classes.

Methods

dump

Dumps out the keys and values

isKey

Returns true if the property is a QgsProjectPropertyKey.

isLeaf

Returns true if property is a leaf node.

isValue

Returns true if the property is a QgsProjectPropertyValue.

readXml

Restores the property hierarchy from a specified DOM node.

value

Returns the node’s value.

writeXml

Writes the property hierarchy to a specified DOM element.

dump(self, tabs: int = 0)

Dumps out the keys and values

Parameters

tabs (int = 0) – is number of tabs to print; used for pretty-printing hierarchy

isKey(self) → bool

Returns true if the property is a QgsProjectPropertyKey.

See also

isValue()

See also

isLeaf()

Return type

bool

isLeaf(self) → bool

Returns true if property is a leaf node.

A leaf node is a key node that has either no value or only a single value. A non-leaf node would be a key node with key sub-nodes.

This is used for entryList() and subkeyList() implementation.

Return type

bool

isValue(self) → bool

Returns true if the property is a QgsProjectPropertyValue.

See also

isKey()

See also

isLeaf()

Return type

bool

readXml(self, keyNode: QDomNode) → bool

Restores the property hierarchy from a specified DOM node.

Used for restoring properties from project file

Parameters

keyNode (QDomNode) –

Return type

bool

value(self) → Any

Returns the node’s value.

For QgsProjectPropertyValue nodes, this is straightforward – just return the embedded QVariant, _value. For QgsProjectPropertyKey, this means returning the QgsProjectPropertyValue _value that is keyed by its name, if it exists; i.e., QgsProjectPropertyKey “foo” will return the property value mapped to its name, “foo”, in its QHash of QProperties.

Return type

Any

writeXml(self, nodeName: str, element: QDomElement, document: QDomDocument) → bool

Writes the property hierarchy to a specified DOM element.

Used for saving properties to project file.

Parameters
  • nodeName (str) – the tag name associated with this element

  • element (QDomElement) – the parent (or encompassing) property element

  • document (QDomDocument) – the overall project file Dom document

Return type

bool