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) { delete m_data; m_data = &data; }
  48
  49     // start drag action, see enum wxDragResult for return value description
  50     //
  51     // if bAllowMove is TRUE, data can be moved, if not - only copied
  52     virtual wxDragResult DoDragDrop(bool bAllowMove = FALSE) = 0;
  53
  54     // override to give feedback depending on the current operation result
  55     // "effect"
  56     virtual bool GiveFeedback( wxDragResult WXUNUSED(effect),
  57                                bool WXUNUSED(bScrolling) )
  58     {
  59         return TRUE;
  60     }
  61
  62 protected:
  63     wxDataObject *m_data;
  64 };
  65
  66 // ----------------------------------------------------------------------------
  67 // wxDropTarget should be associated with a window if it wants to be able to
  68 // receive data via drag and drop.
  69 //
  70 // To use this class, you should derive from wxDropTarget and implement
  71 // OnData() pure virtual method. You may also wish to override OnDrop() if you
  72 // want to accept the data only inside some region of the window (this may
  73 // avoid having to copy the data to this application which happens only when
  74 // OnData() is called)
  75 // ----------------------------------------------------------------------------
  76
  77 class WXDLLEXPORT wxDropTargetBase
  78 {
  79 public:
  80     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
  81     // by wxDropTarget and deleted by it automatically. If you don't give it
  82     // here, you can use SetDataObject() later.
  83     wxDropTargetBase(wxDataObject *dataObject = NULL)
  84         { m_dataObject = dataObject; }
  85     // dtor deletes our data object
  86     virtual ~wxDropTargetBase()
  87         { delete m_dataObject; }
  88
  89     // get/set the associated wxDataObject
  90     wxDataObject *GetDataObject() const
  91         { return m_dataObject; }
  92     void SetDataObject(wxDataObject *dataObject)
  93         { delete m_dataObject; m_dataObject = dataObject; }
  94
  95     // called when mouse enters/leaves the window: might be used to give
  96     // some visual feedback to the user
  97     virtual void OnEnter() { }
  98     virtual void OnLeave() { }
  99
 100     // this function is called when data is dropped at position (x, y) - if it
 101     // returns TRUE, OnData() will be called immediately afterwards which will
 102     // allow to retrieve the data dropped.
 103     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 104
 105     // called after OnDrop() returns TRUE: you will usually just call
 106     // GetData() from here and, probably, also refresh something to update the
 107     // new data
 108     virtual bool OnData(wxCoord x, wxCoord y) = 0;
 109
 110     // may be called *only* from inside OnData() and will fill m_dataObject
 111     // with the data from the drop source if it returns TRUE
 112     virtual bool GetData() = 0;
 113
 114 protected:
 115     wxDataObject *m_dataObject;
 116 };
 117
 118 // ----------------------------------------------------------------------------
 119 // the platform-specific headers also define standard wxDropTarget
 120 // implementations wxTextDropTarget and wxFileDropTarget
 121 // ----------------------------------------------------------------------------
 122
 123 // ----------------------------------------------------------------------------
 124 // include platform dependent class declarations
 125 // ----------------------------------------------------------------------------
 126
 127 #if defined(__WXMSW__)
 128     #include "wx/msw/ole/dropsrc.h"
 129     #include "wx/msw/ole/droptgt.h"
 130 #elif defined(__WXMOTIF__)
 131     #include "wx/motif/dnd.h"
 132 #elif defined(__WXGTK__)
 133     #include "wx/gtk/dnd.h"
 134 #elif defined(__WXQT__)
 135     #include "wx/qt/dnd.h"
 136 #elif defined(__WXMAC__)
 137     #include "wx/mac/dnd.h"
 138 #elif defined(__WXPM__)
 139     #include "wx/os2/dnd.h"
 140 #elif defined(__WXSTUBS__)
 141     #include "wx/stubs/dnd.h"
 142 #endif
 143
 144 #endif // wxUSE_DRAG_AND_DROP
 145
 146 #endif // _WX_DND_H_BASE_