QDragObject(3qt)QDragObject(3qt)NAMEQDragObject - Encapsulates MIME-based information transfer
#include <qdragobject.h>
Inherits QMimeSource and QObject.
Inherited by QIconDrag, QImageDrag, QStoredDrag and
QTextDrag.
Public Members
QDragObject ( QWidget * dragSource = 0, const char * name
= 0 )
virtual ~QDragObject ()
bool drag ()
bool dragMove ()
void dragCopy ()
virtual void setPixmap ( QPixmap )
virtual void setPixmap ( QPixmap, QPoint hotspot )
QPixmap pixmap () const
QPoint pixmapHotSpot () const
QWidget* source ()
enum DragMode { DragDefault, DragCopy, DragMove,
DragCopyOrMove }
Static Public Members
QWidget* target ()
void setTarget ( QWidget * ) (internal)
Protected Members
virtual bool drag ( DragMode )
DESCRIPTION
The QDragObject class encapsulates MIME-based information
transfer.
QDragObject is the base class for all data that needs to
be transferred between and within applications, both for
drag-and-drop and for the clipboard.
See the Drag-and-drop documentation for an overview of how
to provide drag-and-drop in your application.
See the QClipboard documentation for an overview of how to
provide cut-and-paste in your application.
Member Type Documentation
QDragObject::DragMode
This enum type decides which of several types of drag each
individual drag is. The available types are:
DragDefault - the mode is determined heuristically.
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DragCopy - the data is copied, never moved.
DragMove - the data is moved, if dragged at all.
DragCopyOrMove - the user chooses the mode by using
control key to switch from the default.
MEMBER FUNCTION DOCUMENTATIONQDragObject::QDragObject ( QWidget * dragSource = 0, const char *
name = 0 )
Constructs a drag object which is a child of dragSource
and named name.
Note that the drag object will be deleted when dragSource
is.
QDragObject::~QDragObject () [virtual]
Destructs the drag object, canceling any drag-and-drop
operation in which it is involved, and frees up the
storage used.
bool QDragObject::drag ()
Starts a drag operation using the contents of this object,
using DragDefault mode.
The function returns TRUE if the caller should delete the
original copy of the dragged data (but also note
target()).
Note that if the drag contains references to information
(eg. file names is a QUriDrag are references) then the
return value should always be ignored, as the target is
expected to manipulate the referred-to content directly.
On X11 the return value should always be correct anyway,
but on Windows this is not necessarily the case (eg. the
file manager starts a background process to move files, so
the source must not delete the files!).
bool QDragObject::drag ( DragMode mode ) [virtual protected]
Starts a drag operation using the contents of this object.
At this point, the object becomes owned by Qt, not the
application. You should not delete the drag object nor
anything it references. The actual transfer of data to the
target application will be done during future event
processing - after that time the drag object will be
deleted.
Returns TRUE if the dragged data was dragged as a move,
indicating that the caller should remove the original
source of the data (the drag object must continue to have
a copy).
Normally one of simpler drag(), dragMove(), or dragCopy()Trolltech AS 13 June 2001 2
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functions would be used instead.
Warning: in Qt 1.x, drag operations all return FALSE. This
will change in later versions - the functions are provided
in this way to assist preemptive development - code both
move and copy with Qt 1.x to be prepared.
void QDragObject::dragCopy ()
Starts a drag operation using the contents of this object,
using DragCopy mode.
See drag(DragMove) for important further information.
bool QDragObject::dragMove ()
Starts a drag operation using the contents of this object,
using DragMove mode.
QPixmap QDragObject::pixmap () const
Returns the currently set pixmap (which isNull() if none
is set).
QPoint QDragObject::pixmapHotSpot () const
Returns the currently set pixmap hotspot.
void QDragObject::setPixmap ( QPixmap pm, QPoint hotspot )
[virtual]
Set the pixmap pm to display while dragging the object.
The platform-specific implementation will use this in a
loose fashion - so provide a small masked pixmap, but do
not require that the user ever sees it in all its
splendor. In particular, cursors on Windows 95 are of
limited size.
The hotspot is the point on (or off) the pixmap that
should be under the cursor as it is dragged. It is
relative to the top-left pixel of the pixmap.
void QDragObject::setPixmap ( QPixmap pm ) [virtual]
This is an overloaded member function, provided for
convenience. It differs from the above function only in
what argument(s) it accepts.
Uses a hotspot that positions the pixmap below and to the
right of the mouse pointer. This allows the user to
clearly see the point on the window which they are
dragging the data onto.
QWidget * QDragObject::source ()
Returns a pointer to the drag source where this object
originated.
QWidget * QDragObject::target () [static]
After the drag completes, this function will return the
QWidget which received the drop, or 0 if the data was
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QDragObject(3qt)QDragObject(3qt)
dropped on some other program.
This can be useful for detecting the case where drag-and-
drop is to and from the same widget.
void QDragObject::setTarget ( QWidget * t ) [static]
For internal use only.
SEE ALSO
http://doc.trolltech.com/qdragobject.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2001 Trolltech AS,
http://www.trolltech.com. See the license file included
in the distribution for a complete license statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports
make our job much simpler. Thank you.
In case of content or formattting problems with this
manual page, please report them to qt-bugs@trolltech.com.
Please include the name of the manual page
(qdragobject.3qt) and the Qt version (2.3.1).
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