Class: QgsLayerTreeUtils

class qgis.core.QgsLayerTreeUtils

Bases: sip.wrapper

Assorted functions for dealing with layer trees.

Methods

checkStateFromXml

Convert QString to Qt.CheckState

checkStateToXml

Convert Qt.CheckState to QString

collectMapLayersRecursive

Returns map layers from the given list of layer tree nodes.

countMapLayerInTree

Returns how many occurrences of a map layer are there in a layer tree.

firstGroupWithoutCustomProperty

Returns the first parent which doesn’t have the given custom property or the group itself if it doesn’t hold the property

hasLegendFilterExpression

Test if one of the layers in a group has an expression filter

insertLayerBelow

Insert a QgsMapLayer just below another one

invisibleLayerList

Gets invisible layers

layersEditable

Returns True if any of the layers is editable

layersModified

Returns True if any of the layers is modified

legendFilterByExpression

Returns the expression filter of a legend layer

readOldLegend

Try to load layer tree from verbatim <legend> endverbatim tag from project files from QGIS 2.2 and below

readOldLegendLayerOrder

Try to load custom layer order from verbatim <legend> endverbatim tag from project files from QGIS 2.2 and below

removeInvalidLayers

Removes layer nodes that refer to invalid layers

replaceChildrenOfEmbeddedGroups

Remove subtree of embedded groups and replaces it with a custom property embedded-visible-layers

setLegendFilterByExpression

Sets the expression filter of a legend layer

storeOriginalLayersProperties

Stores in a layer’s originalXmlProperties the layer properties information

updateEmbeddedGroupsProjectPath

Updates an embedded group from a project.

writeOldLegend

Returns verbatim <legend> endverbatim tag used in QGIS 2.2 and below

checkStateFromXml(txt: str) → Qt.CheckState

Convert QString to Qt.CheckState

Parameters

txt (str) –

Return type

Qt.CheckState

checkStateToXml(state: Qt.CheckState) → str

Convert Qt.CheckState to QString

Parameters

state (Qt.CheckState) –

Return type

str

collectMapLayersRecursive(nodes: Iterable[QgsLayerTreeNode]) → Set[QgsMapLayer]

Returns map layers from the given list of layer tree nodes. Also recursively visits child nodes of groups.

New in version 3.4.

Parameters

nodes (Iterable[QgsLayerTreeNode]) –

Return type

Set[QgsMapLayer]

countMapLayerInTree(tree: QgsLayerTreeNode, layer: QgsMapLayer) → int

Returns how many occurrences of a map layer are there in a layer tree. In normal situations there is at most one occurrence, but sometimes there may be temporarily more: for example, during drag&drop, upon drop a new layer node is created while the original dragged node is still in the tree, resulting in two occurrences.

This is useful when deciding whether to start or stop listening to a signal of a map layer within a layer tree and only connecting/disconnecting when there is only one occurrence of that layer.

New in version 3.4.

Parameters
Return type

int

firstGroupWithoutCustomProperty(group: QgsLayerTreeGroup, property: str) → QgsLayerTreeGroup

Returns the first parent which doesn’t have the given custom property or the group itself if it doesn’t hold the property

Parameters

New in version 3.8.

Return type

QgsLayerTreeGroup

hasLegendFilterExpression(group: QgsLayerTreeGroup) → bool

Test if one of the layers in a group has an expression filter

Parameters

group (QgsLayerTreeGroup) –

Return type

bool

insertLayerBelow(group: QgsLayerTreeGroup, refLayer: QgsMapLayer, layerToInsert: QgsMapLayer) → QgsLayerTreeLayer

Insert a QgsMapLayer just below another one

Parameters
  • group (QgsLayerTreeGroup) – the tree group where layers are (can be the root group)

  • refLayer (QgsMapLayer) – the reference layer

  • layerToInsert (QgsMapLayer) – the new layer to insert just below the reference layer

Return type

QgsLayerTreeLayer

Returns

the new tree layer

invisibleLayerList(node: QgsLayerTreeNode) → List[str]

Gets invisible layers

Parameters

node (QgsLayerTreeNode) –

Return type

List[str]

layersEditable(layerNodes: Iterable[QgsLayerTreeLayer]) → bool

Returns True if any of the layers is editable

Parameters

layerNodes (Iterable[QgsLayerTreeLayer]) –

Return type

bool

layersModified(layerNodes: Iterable[QgsLayerTreeLayer]) → bool

Returns True if any of the layers is modified

Parameters

layerNodes (Iterable[QgsLayerTreeLayer]) –

Return type

bool

legendFilterByExpression(layer: QgsLayerTreeLayer) → Tuple[str, bool]

Returns the expression filter of a legend layer

Parameters

layer (QgsLayerTreeLayer) –

Return type

Tuple[str, bool]

readOldLegend(root: QgsLayerTreeGroup, legendElem: QDomElement) → bool

Try to load layer tree from verbatim <legend> endverbatim tag from project files from QGIS 2.2 and below

Parameters
Return type

bool

readOldLegendLayerOrder(legendElem: QDomElement, order: Iterable[str]) → Tuple[bool, bool]

Try to load custom layer order from verbatim <legend> endverbatim tag from project files from QGIS 2.2 and below

Parameters
  • legendElem (QDomElement) –

  • order (Iterable[str]) –

Return type

Tuple[bool, bool]

removeInvalidLayers(group: QgsLayerTreeGroup)

Removes layer nodes that refer to invalid layers

Parameters

group (QgsLayerTreeGroup) –

replaceChildrenOfEmbeddedGroups(group: QgsLayerTreeGroup)

Remove subtree of embedded groups and replaces it with a custom property embedded-visible-layers

Parameters

group (QgsLayerTreeGroup) –

setLegendFilterByExpression(layer: QgsLayerTreeLayer, expr: str, enabled: bool = True)

Sets the expression filter of a legend layer

Parameters
storeOriginalLayersProperties(group: QgsLayerTreeGroup, doc: QDomDocument)

Stores in a layer’s originalXmlProperties the layer properties information

New in version 3.6.

Parameters
updateEmbeddedGroupsProjectPath(group: QgsLayerTreeGroup, project: QgsProject)

Updates an embedded group from a project.

Parameters
writeOldLegend(doc: QDomDocument, root: QgsLayerTreeGroup, hasCustomOrder: bool, order: Iterable[QgsMapLayer]) → QDomElement

Returns verbatim <legend> endverbatim tag used in QGIS 2.2 and below

Parameters
Return type

QDomElement