Class: QgsExpressionBuilderWidget

class qgis.gui.QgsExpressionBuilderWidget(parent: QWidget = None)

Bases: PyQt5.QtWidgets.QWidget

Create a new expression builder widget with an optional parent.

A reusable widget that can be used to build a expression string. See QgsExpressionBuilderDialog for example of usage.

Enums

Methods

actionEvent
autosave Auto save the current Python function code.
changeEvent
childEvent
closeEvent
connectNotify
contextMenuEvent
create
customEvent
destroy
disconnectNotify
dragEnterEvent
dragLeaveEvent
dragMoveEvent
dropEvent
enterEvent
evalError Will be set to True if the current expression text reported an eval error with the context.
event
expectedOutputFormat The set expected format string.
expressionContext Returns the expression context for the widget.
expressionText Gets the expression string that has been set in the expression area.
focusInEvent
focusNextChild
focusNextPrevChild
focusOutEvent
focusPreviousChild
hideEvent
initPainter
inputMethodEvent
isExpressionValid
isSignalConnected
keyPressEvent
keyReleaseEvent
leaveEvent
loadAllValues Load all unique values from the set layer into the sample area
loadCodeFromFile Load code from the given file into the function editor
loadFieldNames Loads all the field names from the layer.
loadFieldsAndValues Loads field names and values from the specified map.
loadFunctionCode Load code into the function editor
loadRecent Loads the recent expressions from the given collection.
loadSampleValues Load sample values into the sample value area
metric
model Returns a pointer to the dialog’s function item model.
mouseDoubleClickEvent
mouseMoveEvent
mousePressEvent
mouseReleaseEvent
moveEvent
nativeEvent
newFunctionFile Create a new file in the function editor
paintEvent
parserError Will be set to True if the current expression text reports a parser error with the context.
project Returns the project currently associated with the widget.
receivers
registerItem Registers a node item for the expression builder.
resizeEvent
saveFunctionFile Save the current function editor text to the given file.
saveToRecent Adds the current expression to the given collection.
sender
senderSignalIndex
setAutoSave Enabled or disable auto saving.
setExpectedOutputFormat The set expected format string.
setExpressionContext Sets the expression context for the widget.
setExpressionText Sets the expression string for the widget
setGeomCalculator Sets geometry calculator used in distance/area calculations.
setLayer Sets layer in order to get the fields and values
setProject Sets the project currently associated with the widget.
sharedPainter
showEvent
tabletEvent
timerEvent
updateFunctionFileList Update the list of function files found at the given path
updateMicroFocus
wheelEvent

Signals

evalErrorChanged Will be set to True if the current expression text reported an eval error with the context.
expressionParsed Emitted when the user changes the expression in the widget.
parserErrorChanged Will be set to True if the current expression text reported a parser error with the context.

Attributes

actionEvent()
autosave(self)

Auto save the current Python function code.

changeEvent()
childEvent()
closeEvent()
connectNotify()
contextMenuEvent()
create()
customEvent()
destroy()
disconnectNotify()
dragEnterEvent()
dragLeaveEvent()
dragMoveEvent()
dropEvent()
enterEvent()
evalError(self) → bool

Will be set to True if the current expression text reported an eval error with the context.

New in version 3.0.

evalErrorChanged

Will be set to True if the current expression text reported an eval error with the context.

New in version 3.0: [signal]

event()
expectedOutputFormat(self) → str

The set expected format string. This is pure text format and no expression validation is done against it.

Returns:The expected value format.
expressionContext(self) → QgsExpressionContext

Returns the expression context for the widget. The context is used for the expression preview result and for populating the list of available functions and variables.

New in version 2.12.

expressionParsed

Emitted when the user changes the expression in the widget. Users of this widget should connect to this signal to decide if to let the user continue.

Parameters:isValid – Is True if the expression the user has typed is valid. [signal]
expressionText(self) → str

Gets the expression string that has been set in the expression area.

Returns:The expression as a string. *
focusInEvent()
focusNextChild()
focusNextPrevChild()
focusOutEvent()
focusPreviousChild()
hideEvent()
initPainter()
inputMethodEvent()
isExpressionValid(self) → bool
isSignalConnected()
keyPressEvent()
keyReleaseEvent()
leaveEvent()
loadAllValues(self)

Load all unique values from the set layer into the sample area

loadCodeFromFile(self, path: str)

Load code from the given file into the function editor

loadFieldNames(self)

Loads all the field names from the layer. @remarks Should this really be public couldn’t we just do this for the user?

loadFieldNames(self, fields: QgsFields)

loadFieldsAndValues(self, fieldValues: Dict[str, Iterable[str]])

Loads field names and values from the specified map.

Note

The field values must be quoted appropriately if they are strings.

New in version 2.12.

loadFunctionCode(self, code: str)

Load code into the function editor

loadRecent(self, collection: str = '')

Loads the recent expressions from the given collection. By default it is loaded from the collection “generic”.

loadSampleValues(self)

Load sample values into the sample value area

metric()
model(self) → QStandardItemModel

Returns a pointer to the dialog’s function item model. This method is exposed for testing purposes only - it should not be used to modify the model.

New in version 3.0.

mouseDoubleClickEvent()
mouseMoveEvent()
mousePressEvent()
mouseReleaseEvent()
moveEvent()
nativeEvent()
newFunctionFile(self, fileName: str = '')

Create a new file in the function editor

paintEvent()
parserError(self) → bool

Will be set to True if the current expression text reports a parser error with the context.

New in version 3.0.

parserErrorChanged

Will be set to True if the current expression text reported a parser error with the context.

New in version 3.0: [signal]

project(self) → QgsProject

Returns the project currently associated with the widget.

See also

setProject()

New in version 3.0.

receivers()
registerItem(self, group: str, label: str, expressionText: str, helpText: str = '', type: QgsExpressionItem.ItemType = QgsExpressionItem.ExpressionNode, highlightedItem: bool = False, sortOrder: int = 1, icon: QIcon = QIcon())

Registers a node item for the expression builder.

Parameters:
  • group – The group the item will be show in the tree view. If the group doesn’t exsit it will be created.
  • label – The label that is show to the user for the item in the tree.
  • expressionText – The text that is inserted into the expression area when the user double clicks on the item.
  • helpText – The help text that the user will see when item is selected.
  • type – The type of the expression item.
  • highlightedItem – set to True to make the item highlighted, which inserts a bold copy of the item at the top level
  • sortOrder – sort ranking for item
  • icon – custom icon to show for item
resizeEvent()
saveFunctionFile(self, fileName: str)

Save the current function editor text to the given file.

saveToRecent(self, collection: str = '')

Adds the current expression to the given collection. By default it is saved to the collection “generic”.

sender()
senderSignalIndex()
setAutoSave(self, enabled: bool)

Enabled or disable auto saving. When enabled Python scripts will be auto saved when text changes.

Parameters:enabledTrue to enable auto saving.
setExpectedOutputFormat(self, expected: str)

The set expected format string. This is pure text format and no expression validation is done against it.

Parameters:expected – The expected value format for the expression.

Note

Only a UI hint and not used for expression validation.

setExpressionContext(self, context: QgsExpressionContext)

Sets the expression context for the widget. The context is used for the expression preview result and for populating the list of available functions and variables.

Parameters:context – expression context

New in version 2.12.

setExpressionText(self, expression: str)

Sets the expression string for the widget

setGeomCalculator(self, da: QgsDistanceArea)

Sets geometry calculator used in distance/area calculations.

setLayer(self, layer: QgsVectorLayer)

Sets layer in order to get the fields and values

Note

this needs to be called before calling loadFieldNames().

setProject(self, project: QgsProject)

Sets the project currently associated with the widget. This controls which layers and relations and other project-specific items are shown in the widget.

See also

project()

New in version 3.0.

sharedPainter()
showEvent(self, e: QShowEvent)
tabletEvent()
timerEvent()
updateFunctionFileList(self, path: str)

Update the list of function files found at the given path

updateMicroFocus()
wheelEvent()