The QgsExpressionLineEdit widget includes a line edit for entering expressions together with a button to open the expression creation dialog. More...

#include <qgsexpressionlineedit.h>

Inheritance diagram for QgsExpressionLineEdit:

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Public Slots
void	setExpression (const QString &expression)
	Sets the current expression to show in the widget. More...

Signals
void	expressionChanged (const QString &expression)
	Emitted when the expression is changed. More...

Public Member Functions
	QgsExpressionLineEdit (QWidget *parent=nullptr)
	Constructor for QgsExpressionLineEdit. More...

QString	expectedOutputFormat () const
	Returns the expected format string, which is shown in the expression builder dialog for the widget. More...

QString	expression () const
	Returns the current expression shown in the widget. More...

QString	expressionDialogTitle () const
	Returns the title used for the expression dialog. More...

bool	isValidExpression (QString *expressionError=nullptr) const
	Returns true if the current expression is valid. More...

void	registerExpressionContextGenerator (const QgsExpressionContextGenerator *generator)
	Register an expression context generator class that will be used to retrieve an expression context for the widget. More...

void	setExpectedOutputFormat (const QString &expected)
	Set the expected format string, which is shown in the expression builder dialog for the widget. More...

void	setExpressionDialogTitle (const QString &title)
	Sets the title used in the expression builder dialog. More...

void	setGeomCalculator (const QgsDistanceArea &distanceArea)
	Set the geometry calculator used in the expression dialog. More...

void	setLayer (QgsVectorLayer *layer)
	Sets a layer associated with the widget. More...

void	setMultiLine (bool multiLine)
	Sets whether the widget should show a multiline text editor. More...

Protected Member Functions
void	changeEvent (QEvent *event) override

Friends
class	TestQgsFieldExpressionWidget

Detailed Description

The QgsExpressionLineEdit widget includes a line edit for entering expressions together with a button to open the expression creation dialog.

This widget is designed for use in contexts where no layer fields are available for use in an expression. In contexts where the expression is directly associated with a layer and fields can be used, then QgsFieldExpressionWidget is a more appropriate choice as it gives users direct access to select fields from a drop-down list.

QgsExpressionLineEdit also supports a multiline editor mode which is useful where more space is available for the widget, but where QgsExpressionBuilderWidget is too complex or large for use.

Since: QGIS 3.0

Definition at line 49 of file qgsexpressionlineedit.h.

Constructor & Destructor Documentation

QgsExpressionLineEdit::QgsExpressionLineEdit ( QWidget * parent = nullptr )

explicit

Constructor for QgsExpressionLineEdit.

Parameters

parent parent widget

Definition at line 30 of file qgsexpressionlineedit.cpp.

Member Function Documentation

void QgsExpressionLineEdit::changeEvent ( QEvent * event )

overrideprotected

Definition at line 189 of file qgsexpressionlineedit.cpp.

QString QgsExpressionLineEdit::expectedOutputFormat ( ) const

Returns the expected format string, which is shown in the expression builder dialog for the widget.

This is purely a text format and no expression validation is done against it.

See also: setExpectedOutputFormat()

Since: QGIS 3.4

Definition at line 106 of file qgsexpressionlineedit.cpp.

QString QgsExpressionLineEdit::expression ( ) const

Returns the current expression shown in the widget.

See also: setExpression()

Definition at line 128 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::expressionChanged ( const QString & expression )

signal

Emitted when the expression is changed.

Parameters

expression new expression

QString QgsExpressionLineEdit::expressionDialogTitle ( ) const

inline

Returns the title used for the expression dialog.

See also: setExpressionDialogTitle()

Definition at line 72 of file qgsexpressionlineedit.h.

bool QgsExpressionLineEdit::isValidExpression ( QString * expressionError = nullptr ) const

Returns true if the current expression is valid.

Parameters

expressionError will be set to any generated error message if specified

Definition at line 138 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::registerExpressionContextGenerator ( const QgsExpressionContextGenerator * generator )

Register an expression context generator class that will be used to retrieve an expression context for the widget.

Parameters

generator A QgsExpressionContextGenerator class that will be used to create an expression context when required.

Definition at line 144 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::setExpectedOutputFormat ( const QString & expected )

Set the expected format string, which is shown in the expression builder dialog for the widget.

This is purely a text format and no expression validation is done against it.

See also: expectedOutputFormat()

Since: QGIS 3.4

Definition at line 111 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::setExpression ( const QString & expression )

slot

Sets the current expression to show in the widget.

Parameters

expression expression string

See also: expression()

Definition at line 149 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::setExpressionDialogTitle ( const QString & title )

Sets the title used in the expression builder dialog.

Parameters

title dialog title

See also: expressionDialogTitle()

Definition at line 47 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::setGeomCalculator ( const QgsDistanceArea & distanceArea )

Set the geometry calculator used in the expression dialog.

Parameters

distanceArea calculator

Definition at line 116 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::setLayer ( QgsVectorLayer * layer )

Sets a layer associated with the widget.

Required in order to get the fields and values from the layer. This will also automatically register the layer as expression context generator if no generator has been set before or the previous layer has been used as generator.

See also: registerExpressionContextGenerator

Definition at line 121 of file qgsexpressionlineedit.cpp.

void QgsExpressionLineEdit::setMultiLine ( bool multiLine )

Sets whether the widget should show a multiline text editor.

Parameters

multiLine set to true to show multiline editor, or false to show single line editor (the default).

Definition at line 52 of file qgsexpressionlineedit.cpp.

Friends And Related Function Documentation

friend class TestQgsFieldExpressionWidget

friend

Definition at line 184 of file qgsexpressionlineedit.h.

The documentation for this class was generated from the following files:

/build/qgis-3.4.15+24xenial/src/gui/qgsexpressionlineedit.h
/build/qgis-3.4.15+24xenial/src/gui/qgsexpressionlineedit.cpp

Public Slots

Signals

Public Member Functions

Protected Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation