Class: QgsLayerTree¶

class qgis.core.QgsLayerTree¶

Bases: QgsLayerTreeGroup

Namespace with helper functions for layer tree operations.

Only generally useful routines should be here. Miscellaneous utility functions for work with the layer tree are in QgsLayerTreeUtils class.

New in version 3.0.

QgsLayerTree() Create a new empty layer tree

Methods

childEvent

clear

Clear any information from this layer tree.

clone

rtype

QgsLayerTree

connectNotify

customEvent

customLayerOrder

The order in which layers will be rendered on the canvas.

disconnectNotify

hasCustomLayerOrder

Determines if the layer order should be derived from the layer tree or if a custom override order shall be used instead.

insertChildrenPrivate

Low-level insertion of children to the node.

isGroup

Check whether the node is a valid group node

isLayer

Check whether the node is a valid layer node

isSignalConnected

layerOrder

The order in which layers will be rendered on the canvas.

nodeVisibilityChanged

readCommonXml

Read common XML elements.

readLayerOrderFromXml

Load the layer order from an XML element.

readXml

Load the layer tree from an XML element.

receivers

removeChildrenPrivate

Low-level removal of children from the node.

sender

senderSignalIndex

setCustomLayerOrder

The order in which layers will be rendered on the canvas.

setCustomLayerOrderByIds

The order in which layers will be rendered on the canvas.

setHasCustomLayerOrder

Determines if the layer order should be derived from the layer tree or if a custom override order shall be used instead.

timerEvent

updateChildVisibilityMutuallyExclusive

Set check state of children - if mutually exclusive

writeCommonXml

Write common XML elements.

writeXml

param parentElement

Signals

customLayerOrderChanged

Emitted when the custom layer order has changed.

hasCustomLayerOrderChanged

Emitted when the hasCustomLayerOrder flag changes.

layerOrderChanged

Emitted when the layer order has changed.

childEvent(self, QChildEvent)¶

clear(self)¶: Clear any information from this layer tree.

New in version 3.0.

clone(self) → QgsLayerTree¶

Return type: QgsLayerTree

connectNotify(self, QMetaMethod)¶

customEvent(self, QEvent)¶

customLayerOrder(self) → List[QgsMapLayer]¶

The order in which layers will be rendered on the canvas. Will only be used if the property hasCustomLayerOrder is True. If you need the current layer order that is active, prefer using layerOrder().

See also

setCustomLayerOrder()

See also

layerOrder()

See also

hasCustomLayerOrder()

New in version 3.0.

Return type: List[QgsMapLayer]

customLayerOrderChanged¶: Emitted when the custom layer order has changed.

New in version 3.0: [signal]

disconnectNotify(self, QMetaMethod)¶

hasCustomLayerOrder(self) → bool¶

Determines if the layer order should be derived from the layer tree or if a custom override order shall be used instead.

See also

customLayerOrder()

New in version 3.0.

Return type: bool

hasCustomLayerOrderChanged¶

Emitted when the hasCustomLayerOrder flag changes.

See also

hasCustomLayerOrder()

New in version 3.0: [signal]

Parameters: hasCustomLayerOrder (bool) –

insertChildrenPrivate(self, index: int, nodes: Iterable[QgsLayerTreeNode])¶: Low-level insertion of children to the node. The children must not have any parent yet!

isGroup(node: QgsLayerTreeNode) → bool¶

Check whether the node is a valid group node

New in version 2.4.

Parameters: node (QgsLayerTreeNode) –
Return type: bool

isLayer(node: QgsLayerTreeNode) → bool¶

Check whether the node is a valid layer node

New in version 2.4.

Parameters: node (QgsLayerTreeNode) –
Return type: bool

isSignalConnected(self, QMetaMethod) → bool¶

layerOrder(self) → List[QgsMapLayer]¶

The order in which layers will be rendered on the canvas. Depending on hasCustomLayerOrder, this will return either the override customLayerOrder or the layer order derived from the tree. This property is read only.

See also

customLayerOrder()

New in version 3.0.

Return type: List[QgsMapLayer]

layerOrderChanged¶: Emitted when the layer order has changed.

New in version 3.0: [signal]

nodeVisibilityChanged(self, node: QgsLayerTreeNode)¶

readCommonXml(self, element: QDomElement)¶: Read common XML elements.

readLayerOrderFromXml(self, doc: QDomElement)¶

Load the layer order from an XML element. Make sure that this is only called after the layers are loaded.

New in version 3.0.

Parameters: doc (QDomElement) –

readXml(element: QDomElement, context: QgsReadWriteContext) → QgsLayerTree¶

Load the layer tree from an XML element. It is not required that layers are loaded at this point. resolveReferences() needs to be called after loading the layers and before using the tree.

New in version 3.0.

Parameters

element (QDomElement) –
context (QgsReadWriteContext) –

Return type

QgsLayerTree

receivers(self, PYQT_SIGNAL) → int¶

removeChildrenPrivate(self, from_: int, count: int, destroy: bool = True)¶: Low-level removal of children from the node.

sender(self) → QObject¶

senderSignalIndex(self) → int¶

setCustomLayerOrder(self, customLayerOrder: Iterable[QgsMapLayer])¶

The order in which layers will be rendered on the canvas. Will only be used if the property hasCustomLayerOrder is True. If you need the current layer order that is active, prefer using layerOrder().

See also

customLayerOrder()

See also

layerOrder()

See also

hasCustomLayerOrder()

New in version 3.0.

Parameters: customLayerOrder (Iterable[QgsMapLayer]) –

setCustomLayerOrderByIds(self, customLayerOrder: Iterable[str])¶

The order in which layers will be rendered on the canvas. Will only be used if the property hasCustomLayerOrder is True. If you need the current layer order that is active, prefer using layerOrder().

See also

customLayerOrder()

See also

layerOrder()

See also

hasCustomLayerOrder()

New in version 3.0.

Parameters: customLayerOrder (Iterable[str]) –

setHasCustomLayerOrder(self, hasCustomLayerOrder: bool)¶

Determines if the layer order should be derived from the layer tree or if a custom override order shall be used instead.

See also

setCustomLayerOrder()

New in version 3.0.

Parameters: hasCustomLayerOrder (bool) –

timerEvent(self, QTimerEvent)¶

updateChildVisibilityMutuallyExclusive(self)¶: Set check state of children - if mutually exclusive

writeCommonXml(self, element: QDomElement)¶: Write common XML elements.

writeXml(self, parentElement: QDomElement, context: QgsReadWriteContext)¶

Parameters

parentElement (QDomElement) –
context (QgsReadWriteContext) –