QDesignerPropertySheetExtension#

The QDesignerPropertySheetExtension class allows you to manipulate a widget’s properties which is displayed in Qt Designer’s property editor. More

Inheritance diagram of PySide6.QtDesigner.QDesignerPropertySheetExtension

Detailed Description#

QDesignerPropertySheetExtension provides a collection of functions that are typically used to query a widget’s properties, and to manipulate the properties’ appearance in the property editor. For example:

propertySheet = None()
manager = formEditor.extensionManager()
propertySheet = qt_extension<QDesignerPropertySheetExtension*>(manager, widget)
index = propertySheet.indexOf("margin")
propertySheet.setProperty(index, 10)
propertySheet.setChanged(index, True)
del propertySheet

Note that if you change the value of a property using the setProperty() function, the undo stack is not updated. To ensure that a property’s value can be reverted using the undo stack, you must use the setProperty() function, or its buddy setWidgetProperty() , instead.

When implementing a custom widget plugin, a pointer to Qt Designer's current QDesignerFormEditorInterface object (formEditor in the example above) is provided by the initialize() function’s parameter.

The property sheet, or any other extension, can be retrieved by querying Qt Designer's extension manager using the qt_extension() function. When you want to release the extension, you only need to delete the pointer.

All widgets have a default property sheet which populates Qt Designer's property editor with the widget’s properties (i.e the ones defined with the Q_PROPERTY() macro). But QDesignerPropertySheetExtension also provides an interface for creating custom property sheet extensions.

Keep the following limitations in mind:

  • Qt Designer uses the QDesignerPropertySheetExtension to feed its property editor. Whenever a widget is selected in its workspace, Qt Designer will query for the widget’s property sheet extension. If the selected widget has an implemented property sheet extension, this extension will override the default property sheet.

  • The data types used by the property sheet for some properties are opaque custom QVariant types containing additional information instead of plain Qt data types. For example, this is the case for enumerations, flags, icons, pixmaps and strings.

  • Qt Designer's property editor has no implementation for handling Q_PROPERTY types for custom types that have been declared with Q_DECLARE_METATYPE() .

To create a property sheet extension, your extension class must inherit from both QObject and QDesignerPropertySheetExtension . Then, since we are implementing an interface, we must ensure that it’s made known to the meta object system using the Q_INTERFACES() macro:

class MyPropertySheetExtension(QObject,
        QDesignerPropertySheetExtension = public()

    Q_OBJECT
    Q_INTERFACES(QDesignerPropertySheetExtension)
# public
    ...

This enables Qt Designer to use qobject_cast() to query for supported interfaces using nothing but a QObject pointer.

In Qt Designer the extensions are not created until they are required. For that reason, when implementing a property sheet extension, you must also create a QExtensionFactory , i.e a class that is able to make an instance of your extension, and register it using Qt Designer's extension manager .

When a property sheet extension is required, Qt Designer's extension manager will run through all its registered factories calling createExtension() for each until the first one that is able to create a property sheet extension for the selected widget, is found. This factory will then make an instance of the extension. If no such factory can be found, Qt Designer will use the default property sheet.

There are four available types of extensions in Qt Designer: QDesignerContainerExtension , QDesignerMemberSheetExtension , QDesignerPropertySheetExtension and QDesignerTaskMenuExtension . Qt Designer’s behavior is the same whether the requested extension is associated with a multi page container, a member sheet, a property sheet or a task menu.

The QExtensionFactory class provides a standard extension factory, and can also be used as an interface for custom extension factories. You can either create a new QExtensionFactory and reimplement the createExtension() function. For example:

ANewExtensionFactory::createExtension(QObject = QObject()
        iid, = QString()

    if (iid != Q_TYPEID(QDesignerPropertySheetExtension))
        return 0
    if (MyCustomWidget widget = qobject_cast<MyCustomWidget>
           (object))
        def MyPropertySheetExtension(widget,parent):
    return 0

Or you can use an existing factory, expanding the createExtension() function to make the factory able to create a property sheet extension extension as well. For example:

AGeneralExtensionFactory::createExtension(QObject = QObject()
        iid, = QString()

    widget = MyCustomWidget(object)
    if (widget and (iid == Q_TYPEID(QDesignerTaskMenuExtension))) {
        def MyTaskMenuExtension(widget,parent):
    } else if (widget and (iid == Q_TYPEID(QDesignerPropertySheetExtension))) {
        def MyPropertySheetExtension(widget,parent):
    else:
        return 0

For a complete example using an extension class, see the Task Menu Extension example . The example shows how to create a custom widget plugin for Qt Designer, and how to to use the QDesignerTaskMenuExtension class to add custom items to Qt Designer's task menu.

See also

QDesignerDynamicPropertySheetExtension QExtensionFactory QExtensionManager Creating Custom Widget Extensions

class PySide6.QtDesigner.QDesignerPropertySheetExtension#
PySide6.QtDesigner.QDesignerPropertySheetExtension.count()#
Return type

int

Returns the selected widget’s number of properties.

PySide6.QtDesigner.QDesignerPropertySheetExtension.hasReset(index)#
Parameters

index – int

Return type

bool

Returns true if the property at the given index has a reset button in Qt Designer's property editor, otherwise false.

See also

indexOf() reset()

PySide6.QtDesigner.QDesignerPropertySheetExtension.indexOf(name)#
Parameters

name – str

Return type

int

Returns the index for a given property name.

See also

propertyName()

PySide6.QtDesigner.QDesignerPropertySheetExtension.isAttribute(index)#
Parameters

index – int

Return type

bool

Returns true if the property at the given index is an attribute, which will be excluded from the UI file, otherwise false.

PySide6.QtDesigner.QDesignerPropertySheetExtension.isChanged(index)#
Parameters

index – int

Return type

bool

Returns true if the value of the property at the given index differs from the property’s default value, otherwise false.

PySide6.QtDesigner.QDesignerPropertySheetExtension.isEnabled(index)#
Parameters

index – int

Return type

bool

Returns true if the property at the given index is enabled in Qt Designer's property editor, otherwise false.

See also

indexOf()

PySide6.QtDesigner.QDesignerPropertySheetExtension.isVisible(index)#
Parameters

index – int

Return type

bool

Returns true if the property at the given index is visible in Qt Designer's property editor, otherwise false.

PySide6.QtDesigner.QDesignerPropertySheetExtension.property(index)#
Parameters

index – int

Return type

object

Returns the value of the property at the given index.

PySide6.QtDesigner.QDesignerPropertySheetExtension.propertyGroup(index)#
Parameters

index – int

Return type

str

Returns the property group for the property at the given index.

Qt Designer's property editor supports property groups, i.e. sections of related properties. A property can be related to a group using the setPropertyGroup() function. The default group of any property is the name of the class that defines it. For example, the objectName property appears within the QObject property group.

PySide6.QtDesigner.QDesignerPropertySheetExtension.propertyName(index)#
Parameters

index – int

Return type

str

Returns the name of the property at the given index.

See also

indexOf()

PySide6.QtDesigner.QDesignerPropertySheetExtension.reset(index)#
Parameters

index – int

Return type

bool

Resets the value of the property at the given index, to the default value. Returns true if a default value could be found, otherwise false.

PySide6.QtDesigner.QDesignerPropertySheetExtension.setAttribute(index, b)#
Parameters
  • index – int

  • b – bool

If attribute is true, the property at the given index is made an attribute which will be excluded from the UI file; otherwise it will be included.

PySide6.QtDesigner.QDesignerPropertySheetExtension.setChanged(index, changed)#
Parameters
  • index – int

  • changed – bool

Sets whether the property at the given index is different from its default value, or not, depending on the changed parameter.

PySide6.QtDesigner.QDesignerPropertySheetExtension.setProperty(index, value)#
Parameters
  • index – int

  • value – object

Sets the value of the property at the given index.

Warning

If you change the value of a property using this function, the undo stack is not updated. To ensure that a property’s value can be reverted using the undo stack, you must use the setProperty() function, or its buddy setWidgetProperty() , instead.

PySide6.QtDesigner.QDesignerPropertySheetExtension.setPropertyGroup(index, group)#
Parameters
  • index – int

  • group – str

Sets the property group for the property at the given index to group.

Relating a property to a group makes it appear within that group’s section in the property editor. The default property group of any property is the name of the class that defines it. For example, the objectName property appears within the QObject property group.

PySide6.QtDesigner.QDesignerPropertySheetExtension.setVisible(index, b)#
Parameters
  • index – int

  • b – bool

If visible is true, the property at the given index is visible in Qt Designer's property editor; otherwise the property is hidden.