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 #include "wx/cursor.h"
  21
  22 // ----------------------------------------------------------------------------
  23 // constants
  24 // ----------------------------------------------------------------------------
  25
  26 // result of wxDropSource::DoDragDrop() call
  27 enum wxDragResult
  28 {
  29     wxDragError,    // error prevented the d&d operation from completing
  30     wxDragNone,     // drag target didn't accept the data
  31     wxDragCopy,     // the data was successfully copied
  32     wxDragMove,     // the data was successfully moved (MSW only)
  33     wxDragCancel    // the operation was cancelled by user (not an error)
  34 };
  35
  36 inline WXDLLEXPORT bool wxIsDragResultOk(wxDragResult res)
  37 {
  38     return res == wxDragCopy || res == wxDragMove;
  39 }
  40
  41 // ----------------------------------------------------------------------------
  42 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  43 // to initiate a drag-and-drop operation
  44 // ----------------------------------------------------------------------------
  45
  46 class WXDLLEXPORT wxDropSourceBase
  47 {
  48 public:
  49     wxDropSourceBase(const wxCursor &cursorCopy = wxNullCursor,
  50                      const wxCursor &cursorMove = wxNullCursor,
  51                      const wxCursor &cursorStop = wxNullCursor)
  52         : m_cursorCopy(cursorCopy),
  53           m_cursorMove(cursorMove),
  54           m_cursorStop(cursorStop)
  55         { m_data = (wxDataObject *)NULL; }
  56     virtual ~wxDropSourceBase() { }
  57
  58     // set the data which is transfered by drag and drop
  59     void SetData(wxDataObject& data)
  60       { m_data = &data; }
  61
  62     wxDataObject *GetDataObject()
  63       { return m_data; }
  64
  65     // set the icon corresponding to given drag result
  66     void SetCursor(wxDragResult res, const wxCursor& cursor)
  67     {
  68         if ( res == wxDragCopy )
  69             m_cursorCopy = cursor;
  70         else if ( res == wxDragMove )
  71             m_cursorMove = cursor;
  72         else
  73             m_cursorStop = cursor;
  74     }
  75
  76     // start drag action, see enum wxDragResult for return value description
  77     //
  78     // if bAllowMove is TRUE, data can be moved, if not - only copied
  79     virtual wxDragResult DoDragDrop(bool bAllowMove = FALSE) = 0;
  80
  81     // override to give feedback depending on the current operation result
  82     // "effect" and return TRUE if you did something, FALSE to let the library
  83     // give the default feedback
  84     virtual bool GiveFeedback(wxDragResult WXUNUSED(effect)) { return FALSE; }
  85
  86 protected:
  87     const wxCursor& GetCursor(wxDragResult res) const
  88     {
  89         if ( res == wxDragCopy )
  90             return m_cursorCopy;
  91         else if ( res == wxDragMove )
  92             return m_cursorMove;
  93         else
  94             return m_cursorStop;
  95     }
  96
  97     wxDataObject *m_data;
  98
  99     // the cursors to use for feedback
 100     wxCursor      m_cursorCopy, m_cursorMove, m_cursorStop;
 101 };
 102
 103 // ----------------------------------------------------------------------------
 104 // wxDropTarget should be associated with a window if it wants to be able to
 105 // receive data via drag and drop.
 106 //
 107 // To use this class, you should derive from wxDropTarget and implement
 108 // OnData() pure virtual method. You may also wish to override OnDrop() if you
 109 // want to accept the data only inside some region of the window (this may
 110 // avoid having to copy the data to this application which happens only when
 111 // OnData() is called)
 112 // ----------------------------------------------------------------------------
 113
 114 class WXDLLEXPORT wxDropTargetBase
 115 {
 116 public:
 117     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
 118     // by wxDropTarget and deleted by it automatically. If you don't give it
 119     // here, you can use SetDataObject() later.
 120     wxDropTargetBase(wxDataObject *dataObject = (wxDataObject*)NULL)
 121         { m_dataObject = dataObject; }
 122     // dtor deletes our data object
 123     virtual ~wxDropTargetBase()
 124         { delete m_dataObject; }
 125
 126     // get/set the associated wxDataObject
 127     wxDataObject *GetDataObject() const
 128         { return m_dataObject; }
 129     void SetDataObject(wxDataObject *dataObject)
 130         { if (m_dataObject) delete m_dataObject;
 131     m_dataObject = dataObject; }
 132
 133     // these functions are called when data is moved over position (x, y) and
 134     // may return either wxDragCopy, wxDragMove or wxDragNone depending on
 135     // what would happen if the data were dropped here.
 136     //
 137     // the last parameter is what would happen by default and is determined by
 138     // the platform-specific logic (for example, under Windows it's wxDragCopy
 139     // if Ctrl key is pressed and wxDragMove otherwise) except that it will
 140     // always be wxDragNone if the carried data is in an unsupported format.
 141
 142     // called when the mouse enters the window (only once until OnLeave())
 143     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def)
 144         { return OnDragOver(x, y, def); }
 145
 146     // called when the mouse moves in the window - shouldn't take long to
 147     // execute or otherwise mouse movement would be too slow
 148     virtual wxDragResult OnDragOver(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y),
 149                                     wxDragResult def)
 150         { return def; }
 151
 152     // called when mouse leaves the window: might be used to remove the
 153     // feedback which was given in OnEnter()
 154     virtual void OnLeave() { }
 155
 156     // this function is called when data is dropped at position (x, y) - if it
 157     // returns TRUE, OnData() will be called immediately afterwards which will
 158     // allow to retrieve the data dropped.
 159     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 160
 161     // called after OnDrop() returns TRUE: you will usually just call
 162     // GetData() from here and, probably, also refresh something to update the
 163     // new data and, finally, return the code indicating how did the operation
 164     // complete (returning default value in case of success and wxDragError on
 165     // failure is usually ok)
 166     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def) = 0;
 167
 168     // may be called *only* from inside OnData() and will fill m_dataObject
 169     // with the data from the drop source if it returns TRUE
 170     virtual bool GetData() = 0;
 171
 172 protected:
 173     wxDataObject *m_dataObject;
 174 };
 175
 176 // ----------------------------------------------------------------------------
 177 // include platform dependent class declarations
 178 // ----------------------------------------------------------------------------
 179
 180 #if defined(__WXMSW__)
 181     #include "wx/msw/ole/dropsrc.h"
 182     #include "wx/msw/ole/droptgt.h"
 183 #elif defined(__WXMOTIF__)
 184     #include "wx/motif/dnd.h"
 185 #elif defined(__WXGTK__)
 186     #include "wx/gtk/dnd.h"
 187 #elif defined(__WXQT__)
 188     #include "wx/qt/dnd.h"
 189 #elif defined(__WXMAC__)
 190     #include "wx/mac/dnd.h"
 191 #elif defined(__WXPM__)
 192     #include "wx/os2/dnd.h"
 193 #elif defined(__WXSTUBS__)
 194     #include "wx/stubs/dnd.h"
 195 #endif
 196
 197 // ----------------------------------------------------------------------------
 198 // standard wxDropTarget implementations (implemented in common/dobjcmn.cpp)
 199 // ----------------------------------------------------------------------------
 200
 201 // A simple wxDropTarget derived class for text data: you only need to
 202 // override OnDropText() to get something working
 203 class WXDLLEXPORT wxTextDropTarget : public wxDropTarget
 204 {
 205 public:
 206     wxTextDropTarget();
 207
 208     virtual bool OnDropText(wxCoord x, wxCoord y, const wxString& text) = 0;
 209
 210     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 211 };
 212
 213 // A drop target which accepts files (dragged from File Manager or Explorer)
 214 class WXDLLEXPORT wxFileDropTarget : public wxDropTarget
 215 {
 216 public:
 217     wxFileDropTarget();
 218
 219     // parameters are the number of files and the array of file names
 220     virtual bool OnDropFiles(wxCoord x, wxCoord y,
 221                              const wxArrayString& filenames) = 0;
 222
 223     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 224 };
 225
 226 #endif // wxUSE_DRAG_AND_DROP
 227
 228 #endif // _WX_DND_H_BASE_