include/wx/dnd.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/dnd.h
   3 // Purpose:     Drag and drop classes declarations
   4 // Author:      Vadim Zeitlin, Robert Roebling
   5 // Modified by:
   6 // Created:     26.05.99
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) wxWindows Team
   9 // Licence:     wxWindows license
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_DND_H_BASE_
  13 #define _WX_DND_H_BASE_
  14
  15 #include "wx/defs.h"
  16
  17 #if wxUSE_DRAG_AND_DROP
  18
  19 #include "wx/dataobj.h"
  20
  21 // ----------------------------------------------------------------------------
  22 // constants
  23 // ----------------------------------------------------------------------------
  24
  25 // result of wxDropSource::DoDragDrop() call
  26 enum wxDragResult
  27 {
  28     wxDragError,    // error prevented the d&d operation from completing
  29     wxDragNone,     // drag target didn't accept the data
  30     wxDragCopy,     // the data was successfully copied
  31     wxDragMove,     // the data was successfully moved (MSW only)
  32     wxDragCancel    // the operation was cancelled by user (not an error)
  33 };
  34
  35 // ----------------------------------------------------------------------------
  36 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  37 // to initiate a drag-and-drop operation
  38 // ----------------------------------------------------------------------------
  39
  40 class WXDLLEXPORT wxDropSourceBase
  41 {
  42 public:
  43     wxDropSourceBase() { m_data = (wxDataObject *)NULL; }
  44     virtual ~wxDropSourceBase() { }
  45
  46     // set the data which is transfered by drag and drop
  47     void SetData(wxDataObject& data)
  48       { if (m_data) delete m_data;
  49         m_data = &data; }
  50
  51     // start drag action, see enum wxDragResult for return value description
  52     //
  53     // if bAllowMove is TRUE, data can be moved, if not - only copied
  54     virtual wxDragResult DoDragDrop(bool bAllowMove = FALSE) = 0;
  55
  56     // override to give feedback depending on the current operation result
  57     // "effect"
  58     virtual bool GiveFeedback( wxDragResult WXUNUSED(effect),
  59                                bool WXUNUSED(bScrolling) )
  60     {
  61         return TRUE;
  62     }
  63
  64 protected:
  65     wxDataObject *m_data;
  66 };
  67
  68 // ----------------------------------------------------------------------------
  69 // wxDropTarget should be associated with a window if it wants to be able to
  70 // receive data via drag and drop.
  71 //
  72 // To use this class, you should derive from wxDropTarget and implement
  73 // OnData() pure virtual method. You may also wish to override OnDrop() if you
  74 // want to accept the data only inside some region of the window (this may
  75 // avoid having to copy the data to this application which happens only when
  76 // OnData() is called)
  77 // ----------------------------------------------------------------------------
  78
  79 class WXDLLEXPORT wxDropTargetBase
  80 {
  81 public:
  82     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
  83     // by wxDropTarget and deleted by it automatically. If you don't give it
  84     // here, you can use SetDataObject() later.
  85     wxDropTargetBase(wxDataObject *dataObject = (wxDataObject*)NULL)
  86         { m_dataObject = dataObject; }
  87     // dtor deletes our data object
  88     virtual ~wxDropTargetBase()
  89         { delete m_dataObject; }
  90
  91     // get/set the associated wxDataObject
  92     wxDataObject *GetDataObject() const
  93         { return m_dataObject; }
  94     void SetDataObject(wxDataObject *dataObject)
  95         { if (m_dataObject) delete m_dataObject;
  96           m_dataObject = dataObject; }
  97
  98     // called when mouse enters/leaves the window: might be used to give
  99     // some visual feedback to the user
 100     virtual void OnLeave() { }
 101
 102     // this function is called when data enters over position (x, y) - if it
 103     // returns TRUE, the dragging icon can indicate that the window would
 104     // accept a drop here
 105     virtual bool OnEnter(wxCoord x, wxCoord y) = 0;
 106
 107     // this function is called when data is move over position (x, y) - if it
 108     // returns TRUE, the dragging icon can indicate that the window would
 109     // accept a drop here
 110     virtual bool OnMove(wxCoord x, wxCoord y) = 0;
 111
 112     // this function is called when data is dropped at position (x, y) - if it
 113     // returns TRUE, OnData() will be called immediately afterwards which will
 114     // allow to retrieve the data dropped.
 115     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 116
 117     // called after OnDrop() returns TRUE: you will usually just call
 118     // GetData() from here and, probably, also refresh something to update the
 119     // new data
 120     virtual bool OnData(wxCoord x, wxCoord y) = 0;
 121
 122     // may be called *only* from inside OnData() and will fill m_dataObject
 123     // with the data from the drop source if it returns TRUE
 124     virtual bool GetData() = 0;
 125
 126 protected:
 127     wxDataObject *m_dataObject;
 128 };
 129
 130 // ----------------------------------------------------------------------------
 131 // the platform-specific headers also define standard wxDropTarget
 132 // implementations wxTextDropTarget and wxFileDropTarget
 133 // ----------------------------------------------------------------------------
 134
 135 // ----------------------------------------------------------------------------
 136 // include platform dependent class declarations
 137 // ----------------------------------------------------------------------------
 138
 139 #if defined(__WXMSW__)
 140     #include "wx/msw/ole/dropsrc.h"
 141     #include "wx/msw/ole/droptgt.h"
 142 #elif defined(__WXMOTIF__)
 143     #include "wx/motif/dnd.h"
 144 #elif defined(__WXGTK__)
 145     #include "wx/gtk/dnd.h"
 146 #elif defined(__WXQT__)
 147     #include "wx/qt/dnd.h"
 148 #elif defined(__WXMAC__)
 149     #include "wx/mac/dnd.h"
 150 #elif defined(__WXPM__)
 151     #include "wx/os2/dnd.h"
 152 #elif defined(__WXSTUBS__)
 153     #include "wx/stubs/dnd.h"
 154 #endif
 155
 156 #endif // wxUSE_DRAG_AND_DROP
 157
 158 #endif // _WX_DND_H_BASE_