KParts is
the framework for KDE parts, based on standard KDE/Qt objects, such as QWidget and KTMainWindow. It defines a very simple set of classes: part, plugin, mainwindow, and part
manager. A part,
as previously described, is the name for a KDE component. To define a new part, you need to provide the widget, of course, but also the actions that give access to the part's functionality and an XML file that describes the layout of those actions in the user interface. A plugin
is a small piece of functionality that is not implemented by an embedded widget, but that defines some actions to be merged in the application's user interface, such as the calculator plugin for KSpread. It can be graphical, however, like a dialog box or a separate window popping up, or it can be an application-specific plugin and act on the application itself—a spell checker for a word processor, for example.
A KParts mainwindow
is a special KTMainWindow whose user interface is described in XML and with actions so that it is able to embed parts. The reason it has to use XML is because merging user interfaces is implemented by merging XML documents. A part manager
is a more abstract object whose task is to handle the activation and the deactivation of the parts. Of course, this is useful only for mainwindows that embed more than one part, such as KOffice documents (where the main document is also a part), or Konqueror (where each view is a part). KWrite, which embeds only its own part, doesn't need a part manager.
In the following sections, you create a part for a simple text editor, a main window able to embed an existing PostScript-viewer part, a part manager to embed more than one part, and even a plug-in; thus, you will know everything about KParts.
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