Class: QgsFieldExpressionWidget¶
- class qgis.gui.QgsFieldExpressionWidget¶
Bases:
PyQt5.QtWidgets.QWidget
The
QgsFieldExpressionWidget
class reates a widget to choose fields and edit expressions It contains a combo box to display the fields and expression and a button to open the expression dialog. The combo box is editable, allowing expressions to be edited inline. The validity of the expression is checked live on key press, invalid expressions are displayed in red. The expression will be added to the model (and the fieldChanged signals emitted) only when editing in the line edit is finished (focus lost, enter key pressed).QgsFieldExpressionWidget(parent: QWidget = None)
QgsFieldExpressionWidget
creates a widget with a combo box to display the fields and expression and a button to open the expression dialogMethods
Returns
True
if the combo box allows the empty field ("not set") choice.Allow accepting expressions with evaluation errors.
Appends a scope to the current expression context.
Returns the currently selected field or expression.
- param event
currentField returns the currently selected field or expression if allowed
Returns the current text that is set in the expression area
open the expression dialog to edit the current or add a new expression
- param watched
Returns the currently selected field or expression.
Returns the title used for the expression dialog
when expression is edited by the user in the line edit, it will be checked for validity
when expression has been edited (finished) it will be added to the model
currently used filter on list of fields
If the content is not just a simple field this method will return
True
.- param expressionStr
Returns
True
if the current expression is validReturns the layer currently associated with the widget.
Register an expression context generator class that will be used to retrieve an expression context for the widget.
Sets whether an optional empty field ("not set") option is shown in the combo box.
Allow accepting expressions with evaluation errors.
Sets the current expression text and if applicable also the field.
define the title used in the expression dialog
sets the current field or expression in the widget
Sets the fields used in the widget to
fields
, this allows the widget to work without a layer.setFilters allows filtering according to the type of field
Sets the geometry calculator used in the expression dialog
Sets the layer used to display the fields and expression.
- param isLeft
sets the current row in the widget
updateLineEditStyle will re-style (color/font) the line edit depending on content and status
Signals
Allow accepting expressions with evaluation errors.
Emitted when the currently selected field changes.
- actionEvent(self, QActionEvent)¶
- allowEmptyFieldName(self) bool ¶
Returns
True
if the combo box allows the empty field (“not set”) choice.See also
New in version 3.4.6.
- Return type
bool
- allowEvalErrors(self) bool ¶
Allow accepting expressions with evaluation errors. This can be useful when we are not able to provide an expression context of which we are sure it’s completely populated.
New in version 3.0.
- Return type
bool
- allowEvalErrorsChanged¶
Allow accepting expressions with evaluation errors. This can be useful when we are not able to provide an expression context of which we are sure it’s completely populated.
New in version 3.0: [signal]
- appendScope(self, scope: QgsExpressionContextScope)¶
Appends a scope to the current expression context.
- Parameters
scope (QgsExpressionContextScope) – The scope to add.
New in version 3.2.
- asExpression(self) str ¶
Returns the currently selected field or expression. If a field is currently selected, the returned value will be converted to a valid expression referencing this field (ie enclosing the field name with appropriate quotations).
New in version 2.14.
- Return type
str
- changeEvent(self, event: QEvent)¶
- Parameters
event (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)¶
- currentField(self) Tuple[str, bool, bool] ¶
currentField returns the currently selected field or expression if allowed
- Parameters
isExpression – determines if the string returned is the name of a field or an expression
isValid – determines if the expression (or field) returned is valid
- Return type
Tuple[str, bool, bool]
- currentFieldChanged(self)¶
- currentText(self) str ¶
Returns the current text that is set in the expression area
- Return type
str
- 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)¶
- editExpression(self)¶
open the expression dialog to edit the current or add a new expression
- enterEvent(self, QEvent)¶
- event(self, QEvent) bool ¶
- eventFilter(self, watched: QObject, event: QEvent) bool ¶
- Parameters
watched (QObject) –
event (QEvent) –
- Return type
bool
- expression(self) str ¶
Returns the currently selected field or expression. If a field is currently selected, the returned value will be converted to a valid expression referencing this field (ie enclosing the field name with appropriate quotations).
Alias for
asExpression()
New in version 3.0.
- Return type
str
- expressionDialogTitle(self) str ¶
Returns the title used for the expression dialog
- Return type
str
- expressionEdited(self, expression: str)¶
when expression is edited by the user in the line edit, it will be checked for validity
- Parameters
expression (str) –
- expressionEditingFinished(self)¶
when expression has been edited (finished) it will be added to the model
- fieldChanged¶
Emitted when the currently selected field changes. [signal] fieldChanged(self, fieldName: str, isValid: bool) fieldChanged signal with indication of the validity of the expression [signal]
- Parameters
fieldName (str) –
- filters(self) QgsFieldProxyModel.Filters ¶
currently used filter on list of fields
- Return type
- 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)¶
- isExpression(self) bool ¶
If the content is not just a simple field this method will return
True
.- Return type
bool
- isExpressionValid(self, expressionStr: str) bool ¶
- Parameters
expressionStr (str) –
- Return type
bool
- isSignalConnected(self, QMetaMethod) bool ¶
- isValidExpression(self, expressionError: str = '') bool ¶
Returns
True
if the current expression is valid- Parameters
expressionError (str = '') –
- Return type
bool
- keyPressEvent(self, QKeyEvent)¶
- keyReleaseEvent(self, QKeyEvent)¶
- layer(self) QgsVectorLayer ¶
Returns the layer currently associated with the widget.
See also
- Return type
- 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)¶
- receivers(self, PYQT_SIGNAL) int ¶
- registerExpressionContextGenerator(self, generator: QgsExpressionContextGenerator)¶
Register an expression context generator class that will be used to retrieve an expression context for the widget.
- Parameters
generator (QgsExpressionContextGenerator) – A
QgsExpressionContextGenerator
class that will be used to create an expression context when required.
New in version 3.0.
- resizeEvent(self, QResizeEvent)¶
- sender(self) QObject ¶
- senderSignalIndex(self) int ¶
- setAllowEmptyFieldName(self, allowEmpty: bool)¶
Sets whether an optional empty field (“not set”) option is shown in the combo box.
See also
New in version 3.4.6.
- Parameters
allowEmpty (bool) –
- setAllowEvalErrors(self, allowEvalErrors: bool)¶
Allow accepting expressions with evaluation errors. This can be useful when we are not able to provide an expression context of which we are sure it’s completely populated.
New in version 3.0.
- Parameters
allowEvalErrors (bool) –
- setExpression(self, expression: str)¶
Sets the current expression text and if applicable also the field. Alias for setField.
New in version 3.0.
- Parameters
expression (str) –
- setExpressionDialogTitle(self, title: str)¶
define the title used in the expression dialog
- Parameters
title (str) –
- setField(self, fieldName: str)¶
sets the current field or expression in the widget
- Parameters
fieldName (str) –
- setFields(self, fields: QgsFields)¶
Sets the fields used in the widget to
fields
, this allows the widget to work without a layer.New in version 3.14.
- Parameters
fields (QgsFields) –
- setFilters(self, filters: Union[QgsFieldProxyModel.Filters, QgsFieldProxyModel.Filter])¶
setFilters allows filtering according to the type of field
- Parameters
filters (Union[QgsFieldProxyModel.Filters) –
- setGeomCalculator(self, da: QgsDistanceArea)¶
Sets the geometry calculator used in the expression dialog
- Parameters
da (QgsDistanceArea) –
- setLayer(self, layer: QgsMapLayer)¶
Sets the layer used to display the fields and expression.
See also
- Parameters
layer (QgsMapLayer) –
- setLeftHandButtonStyle(self, isLeft: bool)¶
- Parameters
isLeft (bool) –
- setRow(self, row: int)¶
sets the current row in the widget
- Parameters
row (int) –
- showEvent(self, QShowEvent)¶
- tabletEvent(self, QTabletEvent)¶
- timerEvent(self, QTimerEvent)¶
- updateLineEditStyle(self, expression: str = '')¶
updateLineEditStyle will re-style (color/font) the line edit depending on content and status
- Parameters
expression (str = '') – if expression is given it will be evaluated for the given string, otherwise it takes current expression from the model
- updateMicroFocus(self)¶
- wheelEvent(self, QWheelEvent)¶