The QWidgetFactory class provides for the dynamic creation of widgets
from Qt Designer .ui files.
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Detailed Description
The QWidgetFactory class provides for the dynamic creation of widgets
from Qt Designer .ui files.
This class basically offers two things:
- Dynamically creating widgets from Qt
Designer user interface description files.
You can do this using the static function QWidgetFactory::create().
This function also performs signal and slot connections, tab
ordering, etc., as defined in the .ui file, and returns the
top-level widget in the .ui file. After creating the widget you can
use QObject::child() and QObject::queryList() to access child
widgets of this returned widget.
- Adding additional widget factories to be able to create custom
widgets. See createWidget() for details.
This class is not included in the Qt library itself. To use it you
must link against libqui.so (Unix) or qui.lib (Windows), which is
built into INSTALL/lib if you built Qt Designer (INSTALL is
the directory where Qt is installed ).
If you create a QMainWindow using a QWidgetFactory, be aware that
it already has a central widget. Therefore, you need to delete this
one before setting another one.
See the "Creating Dynamic Dialogs from .ui Files" section of the Qt Designer manual for an example. See
also the QWidgetPlugin class and the Plugins documentation.
Member Function Documentation
QWidgetFactory::QWidgetFactory ()
Constructs a QWidgetFactory.
QWidgetFactory::~QWidgetFactory () [virtual]
Destructor.
void QWidgetFactory::addWidgetFactory ( QWidgetFactory * factory ) [static]
Installs a widget factory factory, which normally contains
additional widgets that can then be created using a QWidgetFactory.
See createWidget() for further details.
QWidget * QWidgetFactory::create ( const QString & uiFile, QObject * connector = 0, QWidget * parent = 0, const char * name = 0 ) [static]
Loads the Qt Designer user interface description file uiFile
and returns the top-level widget in that description. parent and
name are passed to the constructor of the top-level widget.
This function also performs signal and slot connections, tab
ordering, etc., as described in the .ui file. In Qt Designer it
is possible to add custom slots to a form and connect to them. If
you want these connections to be made, you must create a class
derived from QObject, which implements all these slots. Then pass an
instance of the object as connector to this function. If you do
this, the connections to the custom slots will be done using the connector as slot.
If something fails, 0 is returned.
The ownership of the returned widget is passed to the caller.
QWidget * QWidgetFactory::create ( QIODevice * dev, QObject * connector = 0, QWidget * parent = 0, const char * name = 0 ) [static]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Loads the user interface description from device dev.
QWidget * QWidgetFactory::createWidget ( const QString & className, QWidget * parent, const char * name ) const [virtual]
Creates a widget of the type className passing parent and name to its constructor.
If className is a widget in the Qt library, it is directly
created by this function. If the widget isn't in the Qt library,
each of the installed widget plugins is asked, in turn, to create
the widget. As soon as a plugin says it can create the widget it
is asked to do so. It may occur that none of the plugins can
create the widget, in which case each installed widget factory is
asked to create the widget (see addWidgetFactory()). If the widget
cannot be created by any of these means, 0 is returned.
If you have a custom widget, and want it to be created using the
widget factory, there are two approaches you can use:
- Write a widget plugin. This allows you to use the widget in
Qt Designer and in this QWidgetFactory. See the widget plugin
documentation for further details. (See the "Creating Custom
Widgets with Plugins" section of the Qt
Designer manual for an example.
- Subclass QWidgetFactory. Then reimplement this function to
create and return an instance of your custom widget if className equals the name of your widget, otherwise return 0. Then
at the beginning of your program where you want to use the widget
factory to create widgets do a:
QWidgetFactory::addWidgetFactory( new MyWidgetFactory );
where MyWidgetFactory is your QWidgetFactory subclass.
void QWidgetFactory::loadImages ( const QString & dir ) [static]
If you use a pixmap collection (which is the default for new
projects) rather than saving the pixmaps within the .ui XML file,
you must load the pixmap collection. QWidgetFactory looks in the
default QMimeSourceFactory for the pixmaps. Either add it there
manually, or call this function and specify the directory where
the images can be found, as dir. This is normally the
directory called images in the project's directory.
bool QWidgetFactory::supportsWidget ( const QString & widget ) [static]
Returns TRUE if the widget factory can create the specified widget;
otherwise returns FALSE.
QStringList QWidgetFactory::widgets () [static]
Returns the names of the widgets this factory can create.
This file is part of the Qt toolkit.
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