Class: QgsProcessingModelerParameterWidget

class qgis.gui.QgsProcessingModelerParameterWidget(model: QgsProcessingModelAlgorithm, childId: str, parameter: QgsProcessingParameterDefinition, context: QgsProcessingContext, parent: QWidget = None)

Bases: PyQt5.QtWidgets.QWidget, QgsExpressionContextGenerator

Constructor for QgsProcessingModelerParameterWidget, for the specified parameter definition within the given model.

The ID of the child algorithm within the model must be specified via the childId argument. This value corresponds to the QgsProcessingModelChildAlgorithm.childId() string, which uniquely identifies which child algorithm the parameter is associated with inside the given model.

A Processing context must also be specified, which allows the widget to resolve parameter values which are context dependent. The context must last for the lifetime of the widget.

A widget for customising the value of Processing algorithm parameter inside a Processing model.

The widget provides choice of the linked source for values for the parameter inside the model. E.g. parameters can be a static value, an evaluated expression results, the output from another child algorithm, or an input parameter for the model itself.

Individual modeler parameter widgets are not usually created directly, instead they are constructed through the central registry, via calls to QgsGui.processingGuiRegistry()->createModelerParameterWidget().

New in version 3.4.

actionEvent(self, QActionEvent)
changeEvent(self, QEvent)
childEvent(self, QChildEvent)
closeEvent(self, QCloseEvent)
connectNotify(self, QMetaMethod)
contextMenuEvent(self, QContextMenuEvent)
create(self, window: sip.voidptr = 0, initializeWindow: bool = True, destroyOldWindow: bool = True)
Return type


createLabel(self) → QLabel

Creates a label for use identifying the associated parameter.

The caller takes ownership of the returned value.

Return type


customEvent(self, QEvent)
destroy(self, destroyWindow: bool = True, destroySubWindows: bool = True)
disconnectNotify(self, QMetaMethod)
dragEnterEvent(self, QDragEnterEvent)
dragLeaveEvent(self, QDragLeaveEvent)
dragMoveEvent(self, QDragMoveEvent)
dropEvent(self, QDropEvent)
enterEvent(self, QEvent)
event(self, QEvent) → bool
focusInEvent(self, QFocusEvent)
focusNextChild(self) → bool
focusNextPrevChild(self, bool) → bool
focusOutEvent(self, QFocusEvent)
focusPreviousChild(self) → bool
hideEvent(self, QHideEvent)
initPainter(self, QPainter)
inputMethodEvent(self, QInputMethodEvent)
isSignalConnected(self, QMetaMethod) → bool
keyPressEvent(self, QKeyEvent)
keyReleaseEvent(self, QKeyEvent)
leaveEvent(self, QEvent)
metric(self, QPaintDevice.PaintDeviceMetric) → int
mouseDoubleClickEvent(self, QMouseEvent)
mouseMoveEvent(self, QMouseEvent)
mousePressEvent(self, QMouseEvent)
mouseReleaseEvent(self, QMouseEvent)
moveEvent(self, QMoveEvent)
nativeEvent(self, Union[QByteArray, bytes, bytearray], sip.voidptr) → Tuple[bool, int]
paintEvent(self, QPaintEvent)

Returns the parameter definition associated with this wrapper.

Return type


populateSources(self, compatibleParameterTypes: Iterable[str], compatibleOutputTypes: Iterable[str], compatibleDataTypes: Iterable[int])

Populates the widget with available sources for the parameter’s value, e.g. adding the available child algorithm outputs and model input parameter choices.

In order to determine the available source, the compatibleParameterTypes and compatibleOutputTypes arguments are used. These lists correspond to the various available values for QgsProcessingParameterDefinition.type() (for compatibleParameterTypes) and the values for QgsProcessingOutputDefinition.type() (for compatibleOutputTypes).

The compatibleDataTypes list corresponds to the compatible data types from QgsProcessing.SourceType.

  • compatibleParameterTypes (Iterable[str]) –

  • compatibleOutputTypes (Iterable[str]) –

  • compatibleDataTypes (Iterable[int]) –

receivers(self, PYQT_SIGNAL) → int
registerProcessingContextGenerator(self, generator: QgsProcessingContextGenerator)

Registers a Processing context generator class that will be used to retrieve a Processing context for the widget when required.


generator (QgsProcessingContextGenerator) –

resizeEvent(self, QResizeEvent)
sender(self) → QObject
senderSignalIndex(self) → int
setDialog(self, dialog: QDialog)

Sets the parent dialog in which the widget is shown.

New in version 3.8.


dialog (QDialog) –

setExpressionHelpText(self, text: str)

Set the expected expression format text, which is shown in the expression builder dialog for the widget when in the “pre-calculated” expression mode. This is purely a text format and no expression validation is made against it.


text (str) –

setWidgetContext(self, context: QgsProcessingParameterWidgetContext)

Sets the context in which the modeler parameter widget is shown, e.g., the parent model algorithm and other relevant information which allows the widget to fine-tune its behavior.


context (QgsProcessingParameterWidgetContext) –

setWidgetValue(self, value: QgsProcessingModelChildParameterSource)

Sets the current value for the parameter.

See also



value (QgsProcessingModelChildParameterSource) –

sharedPainter(self) → QPainter
showEvent(self, QShowEvent)
tabletEvent(self, QTabletEvent)
timerEvent(self, QTimerEvent)

Returns the current value of the parameter.

See also


Return type


wheelEvent(self, QWheelEvent)