QDesignerCustomWidgetCollectionInterface Class

详细描述

The QDesignerCustomWidgetCollectionInterface class allows you to include several custom widgets in one single library.

When implementing a custom widget plugin, you build it as a separate library. If you want to include several custom widget plugins in the same library, you must in addition subclass QDesignerCustomWidgetCollectionInterface.

QDesignerCustomWidgetCollectionInterface contains one single function returning a list of the collection's QDesignerCustomWidgetInterface objects. For example, if you have several custom widgets CustomWidgetOne, CustomWidgetTwo and CustomWidgetThree, the class definition may look like this:

  #include customwidgetoneinterface.h
  #include customwidgettwointerface.h
  #include customwidgetthreeinterface.h

  #include <QtDesigner/QtDesigner>
  #include <QtCore/qplugin.h>

  class MyCustomWidgets: public QObject, public QDesignerCustomWidgetCollectionInterface
  {
      Q_OBJECT
      Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QDesignerCustomWidgetCollectionInterface")
      Q_INTERFACES(QDesignerCustomWidgetCollectionInterface)

  public:
      MyCustomWidgets(QObject *parent = 0);

      QList<QDesignerCustomWidgetInterface*> customWidgets() const Q_DECL_OVERRIDE;

  private:
      QList<QDesignerCustomWidgetInterface*> widgets;
  };

In the class constructor you add the interfaces to your custom widgets to the list which you return in the customWidgets() function:

  MyCustomWidgets::MyCustomWidgets(QObject *parent)
          : QObject(parent)
  {
      widgets.append(new CustomWidgetOneInterface(this));
      widgets.append(new CustomWidgetTwoInterface(this));
      widgets.append(new CustomWidgetThreeInterface(this));
  }

  QList<QDesignerCustomWidgetInterface*> MyCustomWidgets::customWidgets() const
  {
      return widgets;
  }

Note that instead of exporting each custom widget plugin using the Q_PLUGIN_METADATA() macro, you export the entire collection. The Q_PLUGIN_METADATA() macro ensures that Qt Designer can access and construct the custom widgets. Without this macro, there is no way for Qt Designer to use them.