Class: QgsExpressionBuilderWidget

class qgis.gui.QgsExpressionBuilderWidget

Bases: PyQt5.QtWidgets.QWidget

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

QgsExpressionBuilderWidget(parent: QWidget = None) Create a new expression builder widget with an optional parent.

Methods

actionEvent

autosave

Auto save the current Python function code.

changeEvent

childEvent

closeEvent

connectNotify

contextMenuEvent

create

customEvent

destroy

disconnectNotify

dragEnterEvent

dragLeaveEvent

dragMoveEvent

dropEvent

editSelectedUserExpression

Edits the selected expression from the stored user expressions, the selected expression must be a user stored expression.

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.

expressionTree

Returns the expression tree

findExpressions

Returns the list of expression items matching a label.

focusInEvent

focusNextChild

focusNextPrevChild

focusOutEvent

focusPreviousChild

hideEvent

init

Initialize without any layer

initPainter

initWithFields

Initialize with given fields without any layer

initWithLayer

Initialize with a layer

inputMethodEvent

isExpressionValid

Returns if the expression is valid

isSignalConnected

keyPressEvent

keyReleaseEvent

layer

Returns the current layer or a None.

leaveEvent

loadAllUsedValues

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

loadAllValues

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

loadCodeFromFile

Loads code from the given file into the function editor

loadFieldNames

Deprecated since version QGIS: 3.14

loadFieldsAndValues

Loads field names and values from the specified map.

loadFunctionCode

Loads code into the function editor

loadRecent

Loads the recent expressions from the given collection.

loadSampleUsedValues

Load used sample values into the sample value area.

loadSampleValues

Load sample values into the sample value area.

loadUserExpressions

Loads the user expressions.

metric

model

Returns a pointer to the dialog’s function item model.

mouseDoubleClickEvent

mouseMoveEvent

mousePressEvent

mouseReleaseEvent

moveEvent

nativeEvent

newFunctionFile

Creates 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

removeFromUserExpressions

Removes the expression label from the user stored expressions.

removeSelectedUserExpression

Removes the selected expression from the stored user expressions, the selected expression must be a user stored expression.

resizeEvent

saveFunctionFile

Saves the current function editor text to the given file.

saveToRecent

Adds the current expression to the given collection.

saveToUserExpressions

Stores the user expression with given label and helpText.

sender

senderSignalIndex

setAutoSave

Enabled or disable auto saving.

setExpectedOutputFormat

The set expected format string.

setExpressionContext

Sets the expression context for the widget.

setExpressionPreviewVisible

Sets whether the expression preview is visible.

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

param e

storeCurrentUserExpression

Adds the current expressions to the stored user expressions.

tabletEvent

timerEvent

updateFunctionFileList

Updates 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

LoadAll

LoadNothing

LoadRecent

LoadUserExpressions

class Flag

Bases: int

baseClass

alias of qgis._gui.QgsExpressionBuilderWidget

class Flags
class Flags(Union[QgsExpressionBuilderWidget.Flags, QgsExpressionBuilderWidget.Flag]) None
class Flags(QgsExpressionBuilderWidget.Flags) None

Bases: sip.wrapper

LoadAll = 6
LoadNothing = 0
LoadRecent = 2
LoadUserExpressions = 4
actionEvent(self, QActionEvent)
autosave(self)

Auto save the current Python function code.

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)
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)
editSelectedUserExpression(self)

Edits the selected expression from the stored user expressions, the selected expression must be a user stored expression.

New in version 3.14.

enterEvent(self, QEvent)
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.

Return type

bool

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(self, QEvent) bool
expectedOutputFormat(self) str

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

Return type

str

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.

Return type

QgsExpressionContext

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 (bool) – 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.

Return type

str

Returns

The expression as a string.

expressionTree(self) QgsExpressionTreeView

Returns the expression tree

New in version 3.14.

Return type

QgsExpressionTreeView

findExpressions(self, label: str) List[QgsExpressionItem]

Returns the list of expression items matching a label.

New in version 3.12.

Deprecated since version QGIS: 3.14 use expressionTree()->findExpressions instead

Parameters

label (str) –

Return type

List[QgsExpressionItem]

focusInEvent(self, QFocusEvent)
focusNextChild(self) bool
focusNextPrevChild(self, bool) bool
focusOutEvent(self, QFocusEvent)
focusPreviousChild(self) bool
hideEvent(self, QHideEvent)
init(self, context: QgsExpressionContext = QgsExpressionContext(), recentCollection: str = '', flags: Union[QgsExpressionBuilderWidget.Flags, QgsExpressionBuilderWidget.Flag] = QgsExpressionBuilderWidget.LoadAll)

Initialize without any layer

New in version 3.14.

Parameters
initPainter(self, QPainter)
initWithFields(self, fields: QgsFields, context: QgsExpressionContext = QgsExpressionContext(), recentCollection: str = '', flags: Union[QgsExpressionBuilderWidget.Flags, QgsExpressionBuilderWidget.Flag] = QgsExpressionBuilderWidget.LoadAll)

Initialize with given fields without any layer

New in version 3.14.

Parameters
initWithLayer(self, layer: QgsVectorLayer, context: QgsExpressionContext = QgsExpressionContext(), recentCollection: str = '', flags: Union[QgsExpressionBuilderWidget.Flags, QgsExpressionBuilderWidget.Flag] = QgsExpressionBuilderWidget.LoadAll)

Initialize with a layer

New in version 3.14.

Parameters
inputMethodEvent(self, QInputMethodEvent)
isExpressionValid(self) bool

Returns if the expression is valid

Return type

bool

isSignalConnected(self, QMetaMethod) bool
keyPressEvent(self, QKeyEvent)
keyReleaseEvent(self, QKeyEvent)
layer(self) QgsVectorLayer

Returns the current layer or a None.

Return type

QgsVectorLayer

leaveEvent(self, QEvent)
loadAllUsedValues(self)

Load all unique values from the set layer into the sample area. Only the used ones. Without available values, even if the formatter can provide them (eg. RelationReference).

New in version 3.12.

loadAllValues(self)

Load all unique values from the set layer into the sample area. Including all available values, in case the formatter can provide them (eg. RelationReference).

loadCodeFromFile(self, path: str)

Loads code from the given file into the function editor

Parameters

path (str) –

loadFieldNames(self)

Deprecated since version QGIS: 3.14 this is now done automatically

loadFieldNames(self, fields: QgsFields)

Deprecated since version QGIS: 3.14 use expressionTree()->:py:func:~QgsExpressionBuilderWidget.loadFieldNames instead

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

Loads field names and values from the specified map.

New in version 2.12.

Deprecated since version QGIS: 3.14 this will not do anything, use setLayer() instead

Parameters

fieldValues (Dict[str) –

loadFunctionCode(self, code: str)

Loads code into the function editor

Parameters

code (str) –

loadRecent(self, collection: str = '')

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

Deprecated since version QGIS: 3.14 use expressionTree()->:py:func:~QgsExpressionBuilderWidget.loadRecent instead

Parameters

collection (str = '') –

loadSampleUsedValues(self)

Load used sample values into the sample value area. Only the used ones. Without available values, even if the formatter can provide them (eg. RelationReference).

New in version 3.12.

loadSampleValues(self)

Load sample values into the sample value area. Including available values, in case the formatter can provide them (eg. RelationReference).

loadUserExpressions(self)

Loads the user expressions.

Deprecated since version QGIS: 3.14 use expressionTree()->:py:func:~QgsExpressionBuilderWidget.loadUserExpressions instead

New in version 3.12.

metric(self, QPaintDevice.PaintDeviceMetric) int
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.

Deprecated since version QGIS: 3.14

Return type

QStandardItemModel

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]
newFunctionFile(self, fileName: str = '')

Creates a new file in the function editor

Parameters

fileName (str = '') –

paintEvent(self, QPaintEvent)
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.

Return type

bool

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.

Return type

QgsProject

receivers(self, PYQT_SIGNAL) int
removeFromUserExpressions(self, label: str)

Removes the expression label from the user stored expressions.

Deprecated since version QGIS: 3.14 use expressionTree()->:py:func:~QgsExpressionBuilderWidget.removeFromUserExpressions instead

New in version 3.12.

Parameters

label (str) –

removeSelectedUserExpression(self)

Removes the selected expression from the stored user expressions, the selected expression must be a user stored expression.

New in version 3.12.

resizeEvent(self, QResizeEvent)
saveFunctionFile(self, fileName: str)

Saves the current function editor text to the given file.

Parameters

fileName (str) –

saveToRecent(self, collection: str = '')

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

Deprecated since version QGIS: 3.14 use expressionTree()->:py:func:~QgsExpressionBuilderWidget.saveRecent instead

Parameters

collection (str = '') –

saveToUserExpressions(self, label: str, expression: str, helpText: str)

Stores the user expression with given label and helpText.

Deprecated since version QGIS: 3.14 use expressionTree()->:py:func:~QgsExpressionBuilderWidget.saveToUserExpressions instead

New in version 3.12.

Parameters
  • label (str) –

  • expression (str) –

  • helpText (str) –

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

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

Parameters

enabled (bool) – True 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 (str) – 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 to populate the list of available functions and variables.

Parameters

context (QgsExpressionContext) – expression context

New in version 2.12.

setExpressionPreviewVisible(self, isVisible: bool)

Sets whether the expression preview is visible.

New in version 3.22.

Parameters

isVisible (bool) –

setExpressionText(self, expression: str)

Sets the expression string for the widget

Parameters

expression (str) –

setGeomCalculator(self, da: QgsDistanceArea)

Sets geometry calculator used in distance/area calculations.

Parameters

da (QgsDistanceArea) –

setLayer(self, layer: QgsVectorLayer)

Sets layer in order to get the fields and values

Note

this needs to be called before calling loadFieldNames().

Parameters

layer (QgsVectorLayer) –

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.

Parameters

project (QgsProject) –

sharedPainter(self) QPainter
showEvent(self, e: QShowEvent)
Parameters

e (QShowEvent) –

storeCurrentUserExpression(self)

Adds the current expressions to the stored user expressions.

New in version 3.12.

tabletEvent(self, QTabletEvent)
timerEvent(self, QTimerEvent)
updateFunctionFileList(self, path: str)

Updates the list of function files found at the given path

Parameters

path (str) –

updateMicroFocus(self)
wheelEvent(self, QWheelEvent)