2008-02-18 19:04:03 -05:00
|
|
|
/////////////////////////////////////////////////////////////////////////////
|
2008-02-22 17:05:22 -05:00
|
|
|
// Name: dnd.h
|
2008-02-18 19:04:03 -05:00
|
|
|
// Purpose: topic overview
|
|
|
|
// Author: wxWidgets team
|
|
|
|
// RCS-ID: $Id$
|
2010-07-13 09:29:13 -04:00
|
|
|
// Licence: wxWindows licence
|
2008-02-18 19:04:03 -05:00
|
|
|
/////////////////////////////////////////////////////////////////////////////
|
|
|
|
|
2008-03-12 04:50:42 -04:00
|
|
|
/**
|
2008-02-19 08:28:24 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@page overview_dnd Drag and Drop Overview
|
2008-02-19 08:28:24 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
Classes: wxDataObject, wxTextDataObject, wxDropSource, wxDropTarget,
|
|
|
|
wxTextDropTarget, wxFileDropTarget
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
Note that @c wxUSE_DRAG_AND_DROP must be defined in @c setup.h in order
|
|
|
|
to use drag and drop in wxWidgets.
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
See also: @ref overview_dataobject and @ref page_samples_dnd.
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
It may be noted that data transfer to and from the clipboard is quite
|
|
|
|
similar to data transfer with drag and drop and the code to implement
|
|
|
|
these two types is almost the same. In particular, both data transfer
|
|
|
|
mechanisms store data in some kind of wxDataObject and identify its format(s)
|
|
|
|
using the wxDataFormat class.
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
To be a @e drag source, i.e. to provide the data which may be dragged by
|
|
|
|
the user elsewhere, you should implement the following steps:
|
2008-02-19 08:28:24 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@li @b Preparation: First of all, a data object must be created and
|
|
|
|
initialized with the data you wish to drag. For example:
|
2008-03-20 09:45:17 -04:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@code
|
|
|
|
wxTextDataObject my_data("This text will be dragged.");
|
|
|
|
@endcode
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@li <b>Drag start</b>: To start the dragging process (typically in response to a
|
|
|
|
mouse click) you must call wxDropSource::DoDragDrop like this:
|
2008-03-20 09:45:17 -04:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@code
|
|
|
|
wxDropSource dragSource( this );
|
|
|
|
dragSource.SetData( my_data );
|
|
|
|
wxDragResult result = dragSource.DoDragDrop( true );
|
|
|
|
@endcode
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@li @b Dragging: The call to DoDragDrop() blocks the program until the user releases
|
|
|
|
the mouse button (unless you override the wxDropSource::GiveFeedback function to
|
|
|
|
do something special). When the mouse moves in a window of a program which understands
|
|
|
|
the same drag-and-drop protocol (any program under Windows or any program supporting
|
|
|
|
the XDnD protocol under X Windows), the corresponding wxDropTarget methods
|
|
|
|
are called - see below.
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@li <b>Processing the result</b>: DoDragDrop() returns an @e effect code which
|
|
|
|
is one of the values of @c wxDragResult enum (explained in wxDropTarget page):
|
2008-02-22 17:05:22 -05:00
|
|
|
|
2008-03-22 13:42:29 -04:00
|
|
|
@code
|
|
|
|
switch (result)
|
|
|
|
{
|
2008-03-20 09:45:17 -04:00
|
|
|
case wxDragCopy:
|
2008-02-22 17:05:22 -05:00
|
|
|
// copy the data
|
|
|
|
break;
|
|
|
|
case wxDragMove:
|
|
|
|
// move the data
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
// do nothing
|
|
|
|
break;
|
2008-03-22 13:42:29 -04:00
|
|
|
}
|
|
|
|
@endcode
|
|
|
|
|
|
|
|
|
|
|
|
To be a @e drop target, i.e. to receive the data dropped by the user you should
|
|
|
|
follow the instructions below:
|
|
|
|
|
|
|
|
@li @b Initialization: For a window to be a drop target, it needs to have
|
|
|
|
an associated wxDropTarget object. Normally, you will call wxWindow::SetDropTarget
|
|
|
|
during window creation associating your drop target with it. You must derive a class
|
|
|
|
from wxDropTarget and override its pure virtual methods. Alternatively, you may
|
|
|
|
derive from wxTextDropTarget or wxFileDropTarget and override their OnDropText()
|
|
|
|
or OnDropFiles() method.
|
|
|
|
|
|
|
|
@li @b Drop: When the user releases the mouse over a window, wxWidgets
|
|
|
|
asks the associated wxDropTarget object if it accepts the data. For this,
|
|
|
|
a wxDataObject must be associated with the drop target and this data object will
|
|
|
|
be responsible for the format negotiation between the drag source and the drop target.
|
|
|
|
If all goes well, then wxDropTarget::OnData will get called and the wxDataObject belonging
|
|
|
|
to the drop target can get filled with data.
|
|
|
|
|
|
|
|
@li <b>The end</b>: After processing the data, DoDragDrop() returns either
|
|
|
|
wxDragCopy or wxDragMove depending on the state of the keys Ctrl, Shift
|
|
|
|
and Alt at the moment of the drop. There is currently no way for the drop
|
|
|
|
target to change this return code.
|
2008-02-22 17:05:22 -05:00
|
|
|
|
|
|
|
*/
|
2008-02-19 08:28:24 -05:00
|
|
|
|