QGIS API Documentation
3.0.2-Girona (307d082)
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The QgsFieldExpressionWidget class reates a widget to choose fields and edit expressions It contains a combo boxto display the fields and expression and a button to open the expression dialog. More...
#include <qgsfieldexpressionwidget.h>
Public Slots | |
void | setExpression (const QString &expression) |
Sets the current expression text and if applicable also the field. More... | |
void | setField (const QString &fieldName) |
sets the current field or expression in the widget More... | |
void | setLayer (QgsMapLayer *layer) |
Sets the layer used to display the fields and expression. More... | |
void | setRow (int row) |
sets the current row in the widget More... | |
Signals | |
void | allowEvalErrorsChanged () |
Allow accepting expressions with evaluation errors. More... | |
void | fieldChanged (const QString &fieldName) |
the signal is emitted when the currently selected field changes More... | |
void | fieldChanged (const QString &fieldName, bool isValid) |
fieldChanged signal with indication of the validity of the expression More... | |
Public Member Functions | |
QgsFieldExpressionWidget (QWidget *parent=nullptr) | |
QgsFieldExpressionWidget creates a widget with a combo box to display the fields and expression and a button to open the expression dialog. More... | |
bool | allowEvalErrors () const |
Allow accepting expressions with evaluation errors. More... | |
QString | asExpression () const |
Returns the currently selected field or expression. More... | |
QString | currentField (bool *isExpression=nullptr, bool *isValid=nullptr) const |
currentField returns the currently selected field or expression if allowed More... | |
QString | currentText () const |
Return the current text that is set in the expression area. More... | |
QString | expression () const |
Returns the currently selected field or expression. More... | |
const QString | expressionDialogTitle () |
return the title used for the expression dialog More... | |
QgsFieldProxyModel::Filters | filters () const |
currently used filter on list of fields More... | |
bool | isExpression () const |
If the content is not just a simple field this method will return true. More... | |
bool | isValidExpression (QString *expressionError=nullptr) const |
Return true if the current expression is valid. More... | |
QgsVectorLayer * | layer () const |
Returns the layer currently associated with the widget. 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 | setAllowEvalErrors (bool allowEvalErrors) |
Allow accepting expressions with evaluation errors. More... | |
void | setExpressionDialogTitle (const QString &title) |
define the title used in the expression dialog More... | |
void | setFilters (QgsFieldProxyModel::Filters filters) |
setFilters allows fitering according to the type of field More... | |
void | setGeomCalculator (const QgsDistanceArea &da) |
set the geometry calculator used in the expression dialog More... | |
void | setLeftHandButtonStyle (bool isLeft) |
Protected Slots | |
void | currentFieldChanged () |
void | editExpression () |
open the expression dialog to edit the current or add a new expression More... | |
void | expressionEdited (const QString &expression) |
when expression is edited by the user in the line edit, it will be checked for validity More... | |
void | expressionEditingFinished () |
when expression has been edited (finished) it will be added to the model More... | |
bool | isExpressionValid (const QString &expressionStr) |
void | updateLineEditStyle (const QString &expression=QString()) |
updateLineEditStyle will re-style (color/font) the line edit depending on content and status More... | |
Protected Member Functions | |
void | changeEvent (QEvent *event) override |
Properties | |
bool | allowEvalErrors |
QString | expressionDialogTitle |
QgsFieldProxyModel::Filters | filters |
Friends | |
class | TestQgsFieldExpressionWidget |
The QgsFieldExpressionWidget class reates a widget to choose fields and edit expressions It contains a combo boxto 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).
Definition at line 46 of file qgsfieldexpressionwidget.h.
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explicit |
QgsFieldExpressionWidget creates a widget with a combo box to display the fields and expression and a button to open the expression dialog.
Definition at line 28 of file qgsfieldexpressionwidget.cpp.
bool QgsFieldExpressionWidget::allowEvalErrors | ( | ) | const |
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.
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signal |
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.
QString QgsFieldExpressionWidget::asExpression | ( | ) | const |
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).
Definition at line 108 of file qgsfieldexpressionwidget.cpp.
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overrideprotected |
Definition at line 247 of file qgsfieldexpressionwidget.cpp.
QString QgsFieldExpressionWidget::currentField | ( | bool * | isExpression = nullptr , |
bool * | isValid = nullptr |
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) | const |
currentField returns the currently selected field or expression if allowed
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 |
Definition at line 129 of file qgsfieldexpressionwidget.cpp.
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protectedslot |
Definition at line 286 of file qgsfieldexpressionwidget.cpp.
QString QgsFieldExpressionWidget::currentText | ( | ) | const |
Return the current text that is set in the expression area.
Definition at line 103 of file qgsfieldexpressionwidget.cpp.
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protectedslot |
open the expression dialog to edit the current or add a new expression
Definition at line 209 of file qgsfieldexpressionwidget.cpp.
QString QgsFieldExpressionWidget::expression | ( | ) | const |
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()
Definition at line 113 of file qgsfieldexpressionwidget.cpp.
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inline |
return the title used for the expression dialog
Definition at line 64 of file qgsfieldexpressionwidget.h.
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protectedslot |
when expression is edited by the user in the line edit, it will be checked for validity
Definition at line 231 of file qgsfieldexpressionwidget.cpp.
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protectedslot |
when expression has been edited (finished) it will be added to the model
Definition at line 237 of file qgsfieldexpressionwidget.cpp.
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signal |
the signal is emitted when the currently selected field changes
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signal |
fieldChanged signal with indication of the validity of the expression
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inline |
currently used filter on list of fields
Definition at line 72 of file qgsfieldexpressionwidget.h.
bool QgsFieldExpressionWidget::isExpression | ( | ) | const |
If the content is not just a simple field this method will return true.
Definition at line 124 of file qgsfieldexpressionwidget.cpp.
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protectedslot |
Definition at line 343 of file qgsfieldexpressionwidget.cpp.
bool QgsFieldExpressionWidget::isValidExpression | ( | QString * | expressionError = nullptr | ) | const |
Return true if the current expression is valid.
Definition at line 118 of file qgsfieldexpressionwidget.cpp.
QgsVectorLayer * QgsFieldExpressionWidget::layer | ( | ) | const |
Returns the layer currently associated with the widget.
Definition at line 145 of file qgsfieldexpressionwidget.cpp.
void QgsFieldExpressionWidget::registerExpressionContextGenerator | ( | const QgsExpressionContextGenerator * | generator | ) |
Register an expression context generator class that will be used to retrieve an expression context for the widget.
generator | A QgsExpressionContextGenerator class that will be used to create an expression context when required. |
Definition at line 150 of file qgsfieldexpressionwidget.cpp.
void QgsFieldExpressionWidget::setAllowEvalErrors | ( | bool | allowEvalErrors | ) |
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.
Definition at line 277 of file qgsfieldexpressionwidget.cpp.
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slot |
Sets the current expression text and if applicable also the field.
Alias for setField.
Definition at line 204 of file qgsfieldexpressionwidget.cpp.
void QgsFieldExpressionWidget::setExpressionDialogTitle | ( | const QString & | title | ) |
define the title used in the expression dialog
Definition at line 73 of file qgsfieldexpressionwidget.cpp.
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slot |
sets the current field or expression in the widget
Definition at line 173 of file qgsfieldexpressionwidget.cpp.
void QgsFieldExpressionWidget::setFilters | ( | QgsFieldProxyModel::Filters | filters | ) |
setFilters allows fitering according to the type of field
Definition at line 78 of file qgsfieldexpressionwidget.cpp.
void QgsFieldExpressionWidget::setGeomCalculator | ( | const QgsDistanceArea & | da | ) |
set the geometry calculator used in the expression dialog
Definition at line 98 of file qgsfieldexpressionwidget.cpp.
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slot |
Sets the layer used to display the fields and expression.
Definition at line 155 of file qgsfieldexpressionwidget.cpp.
void QgsFieldExpressionWidget::setLeftHandButtonStyle | ( | bool | isLeft | ) |
Definition at line 83 of file qgsfieldexpressionwidget.cpp.
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inlineslot |
sets the current row in the widget
Definition at line 173 of file qgsfieldexpressionwidget.h.
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protectedslot |
updateLineEditStyle will re-style (color/font) the line edit depending on content and status
expression | if expression is given it will be evaluated for the given string, otherwise it takes current expression from the model |
Definition at line 308 of file qgsfieldexpressionwidget.cpp.
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friend |
Definition at line 227 of file qgsfieldexpressionwidget.h.
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readwrite |
Definition at line 51 of file qgsfieldexpressionwidget.h.
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readwrite |
Definition at line 49 of file qgsfieldexpressionwidget.h.
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readwrite |
Definition at line 50 of file qgsfieldexpressionwidget.h.