QExtensionFactory Class Reference
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QtDesigner

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The QExtensionFactory class allows you to create a factory that is able to make instances of custom extensions in Qt Designer. 更多...

继承 QObject and QAbstractExtensionFactory .

方法

__init__ ( self , QExtensionManager parent = None)
QObject createExtension ( self , QObject object , QString iid , QObject parent )
QObject extension ( self , QObject object , QString iid )
QExtensionManager extensionManager ( self )

详细描述

The QExtensionFactory class allows you to create a factory that is able to make instances of custom extensions in Qt Designer.

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

QExtensionManager class provides extension management facilities for Qt Designer. When an extension is required, Qt Designer's extension manager will run through all its registered factories calling QExtensionFactory.createExtension () for each until the first one that is able to create a requested extension for the selected object, is found. This factory will then make an instance of the extension.

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.

You can either create a new QExtensionFactory and reimplement the QExtensionFactory.createExtension () function. For example:

         QObject *ANewExtensionFactory.createExtension(QObject *object,
                 const QString &iid, QObject *parent) const
         {
             if (iid != Q_TYPEID(QDesignerContainerExtension))
                 return 0;
             if (MyCustomWidget *widget = qobject_cast<MyCustomWidget*>
                    (object))
                 return new MyContainerExtension(widget, parent);
             return 0;
         }

Or you can use an existing factory, expanding the QExtensionFactory.createExtension () function to make the factory able to create your extension as well. 例如：

         QObject *AGeneralExtensionFactory.createExtension(QObject *object,
                 const QString &iid, QObject *parent) const
         {
             MyCustomWidget *widget = qobject_cast<MyCustomWidget*>(object);
             if (widget && (iid == Q_TYPEID(QDesignerTaskMenuExtension))) {
                 return new MyTaskMenuExtension(widget, parent);
             } else if (widget && (iid == Q_TYPEID(QDesignerContainerExtension))) {
                 return new MyContainerExtension(widget, parent);
             } else {
                 return 0;
             }
         }

For a complete example using the QExtensionFactory 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.

方法文档编制

QExtensionFactory.init ( self , QExtensionManager parent = None)

parent argument, if not None, causes self to be owned by Qt instead of PyQt.

Constructs an extension factory with the given parent .

QObject QExtensionFactory.createExtension ( self , QObject object , QString iid , QObject parent )

parent argument, if not None, causes self to be owned by Qt instead of PyQt.

Creates an extension specified by iid 为给定 object . The extension object is created as a child of the specified parent .

另请参阅 extension ().

QObject QExtensionFactory.extension ( self , QObject object , QString iid )

重实现自 QAbstractExtensionFactory.extension ().

Returns the extension specified by iid 为给定 object .

另请参阅 createExtension ().

QExtensionManager QExtensionFactory.extensionManager ( self )

Returns the extension manager for the extension factory.

QExtensionFactory Class Reference [ QtDesigner module]

方法