QGIS API Documentation 3.39.0-Master (3783037d301)
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A reusable widget that can be used to build a expression string. More...
#include <qgsexpressionbuilderwidget.h>
Public Types | |
enum | Flag { LoadNothing = 0 , LoadRecent = 1 << 1 , LoadUserExpressions = 1 << 2 , LoadAll = LoadRecent | LoadUserExpressions } |
Flag to determine what should be loaded. More... | |
typedef QFlags< Flag > | Flags |
Public Slots | |
void | autosave () |
Auto save the current Python function code. | |
void | editSelectedUserExpression () |
Edits the selected expression from the stored user expressions, the selected expression must be a user stored expression. | |
const QList< QgsExpressionItem * > | findExpressions (const QString &label) |
Returns the list of expression items matching a label. | |
void | loadAllUsedValues () |
Load all unique values from the set layer into the sample area. | |
void | loadAllValues () |
Load all unique values from the set layer into the sample area. | |
void | loadSampleUsedValues () |
Load used sample values into the sample value area. | |
void | loadSampleValues () |
Load sample values into the sample value area. | |
void | removeSelectedUserExpression () |
Removes the selected expression from the stored user expressions, the selected expression must be a user stored expression. | |
void | setAutoSave (bool enabled) |
Enabled or disable auto saving. | |
void | storeCurrentUserExpression () |
Adds the current expressions to the stored user expressions. | |
Signals | |
void | evalErrorChanged () |
Will be set to true if the current expression text reported an eval error with the context. | |
void | expressionParsed (bool isValid) |
Emitted when the user changes the expression in the widget. | |
void | parserErrorChanged () |
Will be set to true if the current expression text reported a parser error with the context. | |
Public Member Functions | |
QgsExpressionBuilderWidget (QWidget *parent=nullptr) | |
Create a new expression builder widget with an optional parent. | |
~QgsExpressionBuilderWidget () override | |
bool | evalError () const |
Will be set to true if the current expression text reported an eval error with the context. | |
QString | expectedOutputFormat () |
The set expected format string. | |
QgsExpressionContext | expressionContext () const |
Returns the expression context for the widget. | |
QString | expressionText () |
Gets the expression string that has been set in the expression area. | |
QgsExpressionTreeView * | expressionTree () const |
Returns the expression tree. | |
void | init (const QgsExpressionContext &context=QgsExpressionContext(), const QString &recentCollection=QStringLiteral("generic"), QgsExpressionBuilderWidget::Flags flags=LoadAll) |
Initialize without any layer. | |
void | initWithFields (const QgsFields &fields, const QgsExpressionContext &context=QgsExpressionContext(), const QString &recentCollection=QStringLiteral("generic"), QgsExpressionBuilderWidget::Flags flags=LoadAll) |
Initialize with given fields without any layer. | |
void | initWithLayer (QgsVectorLayer *layer, const QgsExpressionContext &context=QgsExpressionContext(), const QString &recentCollection=QStringLiteral("generic"), QgsExpressionBuilderWidget::Flags flags=LoadAll) |
Initialize with a layer. | |
bool | isExpressionValid () |
Returns if the expression is valid. | |
QgsVectorLayer * | layer () const |
Returns the current layer or a nullptr. | |
void | loadCodeFromFile (QString path) |
Loads code from the given file into the function editor. | |
void | loadCodeFromProjectFunctions () |
Loads code from the project into the function editor. | |
Q_DECL_DEPRECATED void | loadFieldNames () |
Q_DECL_DEPRECATED void | loadFieldNames (const QgsFields &fields) |
Q_DECL_DEPRECATED void | loadFieldsAndValues (const QMap< QString, QStringList > &fieldValues) |
Loads field names and values from the specified map. | |
void | loadFunctionCode (const QString &code) |
Loads code into the function editor. | |
Q_DECL_DEPRECATED void | loadRecent (const QString &collection=QStringLiteral("generic")) |
Loads the recent expressions from the given collection. | |
Q_DECL_DEPRECATED void | loadUserExpressions () |
Loads the user expressions. | |
Q_DECL_DEPRECATED QStandardItemModel * | model () |
Returns a pointer to the dialog's function item model. | |
void | newFunctionFile (const QString &fileName="scratch") |
Creates a new file in the function editor. | |
bool | parserError () const |
Will be set to true if the current expression text reports a parser error with the context. | |
QgsProject * | project () |
Returns the project currently associated with the widget. | |
Q_DECL_DEPRECATED void | removeFromUserExpressions (const QString &label) |
Removes the expression label from the user stored expressions. | |
void | saveFunctionFile (QString fileName) |
Saves the current function editor text to the given file. | |
void | saveProjectFunctionsEntry () |
Saves the current function editor text to a project entry. | |
Q_DECL_DEPRECATED void | saveToRecent (const QString &collection="generic") |
Adds the current expression to the given collection. | |
Q_DECL_DEPRECATED void | saveToUserExpressions (const QString &label, const QString &expression, const QString &helpText) |
Stores the user expression with given label and helpText. | |
void | setCustomPreviewGenerator (const QString &label, const QList< QPair< QString, QVariant > > &choices, const std::function< QgsExpressionContext(const QVariant &) > &previewContextGenerator) |
Sets the widget to run using a custom preview generator. | |
void | setExpectedOutputFormat (const QString &expected) |
The set expected format string. | |
void | setExpressionContext (const QgsExpressionContext &context) |
Sets the expression context for the widget. | |
void | setExpressionPreviewVisible (bool isVisible) |
Sets whether the expression preview is visible. | |
void | setExpressionText (const QString &expression) |
Sets the expression string for the widget. | |
void | setGeomCalculator (const QgsDistanceArea &da) |
Sets geometry calculator used in distance/area calculations. | |
void | setLayer (QgsVectorLayer *layer) |
Sets layer in order to get the fields and values. | |
void | setProject (QgsProject *project) |
Sets the project currently associated with the widget. | |
void | updateFunctionFileList (const QString &path) |
Updates the list of function files found at the given path. | |
Protected Member Functions | |
void | showEvent (QShowEvent *e) override |
A reusable widget that can be used to build a expression string.
See QgsExpressionBuilderDialog for example of usage.
Definition at line 46 of file qgsexpressionbuilderwidget.h.
typedef QFlags< Flag > QgsExpressionBuilderWidget::Flags |
Definition at line 62 of file qgsexpressionbuilderwidget.h.
Flag to determine what should be loaded.
Enumerator | |
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LoadNothing | Do not load anything. |
LoadRecent | Load recent expressions given the collection key. |
LoadUserExpressions | Load user expressions. |
LoadAll | Load everything. |
Definition at line 55 of file qgsexpressionbuilderwidget.h.
QgsExpressionBuilderWidget::QgsExpressionBuilderWidget | ( | QWidget * | parent = nullptr | ) |
Create a new expression builder widget with an optional parent.
Definition at line 72 of file qgsexpressionbuilderwidget.cpp.
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override |
Definition at line 247 of file qgsexpressionbuilderwidget.cpp.
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slot |
Auto save the current Python function code.
Definition at line 1063 of file qgsexpressionbuilderwidget.cpp.
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slot |
Edits the selected expression from the stored user expressions, the selected expression must be a user stored expression.
Definition at line 1104 of file qgsexpressionbuilderwidget.cpp.
bool QgsExpressionBuilderWidget::evalError | ( | ) | const |
Will be set to true
if the current expression text reported an eval error with the context.
Definition at line 796 of file qgsexpressionbuilderwidget.cpp.
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signal |
Will be set to true
if the current expression text reported an eval error with the context.
QString QgsExpressionBuilderWidget::expectedOutputFormat | ( | ) |
The set expected format string.
This is pure text format and no expression validation is done against it.
Definition at line 759 of file qgsexpressionbuilderwidget.cpp.
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inline |
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.
Definition at line 145 of file qgsexpressionbuilderwidget.h.
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signal |
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.
isValid | Is true if the expression the user has typed is valid. |
QString QgsExpressionBuilderWidget::expressionText | ( | ) |
Gets the expression string that has been set in the expression area.
Definition at line 749 of file qgsexpressionbuilderwidget.cpp.
QgsExpressionTreeView * QgsExpressionBuilderWidget::expressionTree | ( | ) | const |
Returns the expression tree.
Definition at line 722 of file qgsexpressionbuilderwidget.cpp.
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slot |
Returns the list of expression items matching a label.
Definition at line 1232 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::init | ( | const QgsExpressionContext & | context = QgsExpressionContext() , |
const QString & | recentCollection = QStringLiteral( "generic" ) , |
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QgsExpressionBuilderWidget::Flags | flags = LoadAll |
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Initialize without any layer.
Definition at line 256 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::initWithFields | ( | const QgsFields & | fields, |
const QgsExpressionContext & | context = QgsExpressionContext() , |
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const QString & | recentCollection = QStringLiteral( "generic" ) , |
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QgsExpressionBuilderWidget::Flags | flags = LoadAll |
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) |
Initialize with given fields without any layer.
Definition at line 273 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::initWithLayer | ( | QgsVectorLayer * | layer, |
const QgsExpressionContext & | context = QgsExpressionContext() , |
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const QString & | recentCollection = QStringLiteral( "generic" ) , |
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QgsExpressionBuilderWidget::Flags | flags = LoadAll |
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) |
Initialize with a layer.
Definition at line 267 of file qgsexpressionbuilderwidget.cpp.
bool QgsExpressionBuilderWidget::isExpressionValid | ( | ) |
Returns if the expression is valid.
Definition at line 702 of file qgsexpressionbuilderwidget.cpp.
QgsVectorLayer * QgsExpressionBuilderWidget::layer | ( | ) | const |
Returns the current layer or a nullptr.
Definition at line 303 of file qgsexpressionbuilderwidget.cpp.
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slot |
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).
Definition at line 1034 of file qgsexpressionbuilderwidget.cpp.
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slot |
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).
Definition at line 994 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::loadCodeFromFile | ( | QString | path | ) |
Loads code from the given file into the function editor.
Definition at line 577 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::loadCodeFromProjectFunctions | ( | ) |
Loads code from the project into the function editor.
Definition at line 585 of file qgsexpressionbuilderwidget.cpp.
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inline |
Definition at line 102 of file qgsexpressionbuilderwidget.h.
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inline |
Definition at line 105 of file qgsexpressionbuilderwidget.h.
void QgsExpressionBuilderWidget::loadFieldsAndValues | ( | const QMap< QString, QStringList > & | fieldValues | ) |
Loads field names and values from the specified map.
Definition at line 602 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::loadFunctionCode | ( | const QString & | code | ) |
Loads code into the function editor.
Definition at line 590 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::loadRecent | ( | const QString & | collection = QStringLiteral( "generic" ) | ) |
Loads the recent expressions from the given collection.
By default it is loaded from the collection "generic".
Definition at line 717 of file qgsexpressionbuilderwidget.cpp.
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slot |
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).
Definition at line 1014 of file qgsexpressionbuilderwidget.cpp.
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slot |
Load sample values into the sample value area.
Including available values, in case the formatter can provide them (eg. RelationReference).
Definition at line 974 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::loadUserExpressions | ( | ) |
Loads the user expressions.
Definition at line 728 of file qgsexpressionbuilderwidget.cpp.
QStandardItemModel * QgsExpressionBuilderWidget::model | ( | ) |
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.
Definition at line 801 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::newFunctionFile | ( | const QString & | fileName = "scratch" | ) |
Creates a new file in the function editor.
Definition at line 451 of file qgsexpressionbuilderwidget.cpp.
bool QgsExpressionBuilderWidget::parserError | ( | ) | const |
Will be set to true
if the current expression text reports a parser error with the context.
Definition at line 786 of file qgsexpressionbuilderwidget.cpp.
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signal |
Will be set to true
if the current expression text reported a parser error with the context.
QgsProject * QgsExpressionBuilderWidget::project | ( | ) |
Returns the project currently associated with the widget.
Definition at line 808 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::removeFromUserExpressions | ( | const QString & | label | ) |
Removes the expression label from the user stored expressions.
Definition at line 738 of file qgsexpressionbuilderwidget.cpp.
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slot |
Removes the selected expression from the stored user expressions, the selected expression must be a user stored expression.
Definition at line 1133 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::saveFunctionFile | ( | QString | fileName | ) |
Saves the current function editor text to the given file.
Definition at line 380 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::saveProjectFunctionsEntry | ( | ) |
Saves the current function editor text to a project entry.
Definition at line 406 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::saveToRecent | ( | const QString & | collection = "generic" | ) |
Adds the current expression to the given collection.
By default it is saved to the collection "generic".
Definition at line 712 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::saveToUserExpressions | ( | const QString & | label, |
const QString & | expression, | ||
const QString & | helpText | ||
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Stores the user expression with given label and helpText.
Definition at line 733 of file qgsexpressionbuilderwidget.cpp.
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inlineslot |
Enabled or disable auto saving.
When enabled Python scripts will be auto saved when text changes.
enabled | true to enable auto saving. |
Definition at line 380 of file qgsexpressionbuilderwidget.h.
void QgsExpressionBuilderWidget::setCustomPreviewGenerator | ( | const QString & | label, |
const QList< QPair< QString, QVariant > > & | choices, | ||
const std::function< QgsExpressionContext(const QVariant &) > & | previewContextGenerator | ||
) |
Sets the widget to run using a custom preview generator.
In this mode, the widget will call a callback function to generate a new QgsExpressionContext as the previewed object changes. This can be used to provide custom preview values for different objects (i.e. for objects which aren't vector layer features).
label | The label to display for the combo box presenting choices of objects. This should be a representative name, eg "Band" if the widget is showing choices of raster layer bands |
choices | A list of choices to present to the user. Each choice is a pair of a human-readable label and a QVariant representing the object to preview. |
previewContextGenerator | A function which takes a QVariant representing the object to preview, and returns a QgsExpressionContext to use for previewing the object. |
Definition at line 707 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::setExpectedOutputFormat | ( | const QString & | expected | ) |
The set expected format string.
This is pure text format and no expression validation is done against it.
expected | The expected value format for the expression. |
Definition at line 764 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::setExpressionContext | ( | const QgsExpressionContext & | context | ) |
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.
context | expression context |
Definition at line 770 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::setExpressionPreviewVisible | ( | bool | isVisible | ) |
Sets whether the expression preview is visible.
Definition at line 791 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::setExpressionText | ( | const QString & | expression | ) |
Sets the expression string for the widget.
Definition at line 754 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::setGeomCalculator | ( | const QgsDistanceArea & | da | ) |
Sets geometry calculator used in distance/area calculations.
Definition at line 744 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::setLayer | ( | QgsVectorLayer * | layer | ) |
Sets layer in order to get the fields and values.
Definition at line 280 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::setProject | ( | QgsProject * | project | ) |
Sets the project currently associated with the widget.
This controls which layers and relations and other project-specific items are shown in the widget.
Definition at line 813 of file qgsexpressionbuilderwidget.cpp.
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overrideprotected |
Definition at line 819 of file qgsexpressionbuilderwidget.cpp.
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slot |
Adds the current expressions to the stored user expressions.
Definition at line 1094 of file qgsexpressionbuilderwidget.cpp.
void QgsExpressionBuilderWidget::updateFunctionFileList | ( | const QString & | path | ) |
Updates the list of function files found at the given path.
Definition at line 411 of file qgsexpressionbuilderwidget.cpp.