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 #ifdef __GNUG__
  16     #pragma interface "dndbase.h"
  17 #endif
  18
  19 #include "wx/defs.h"
  20
  21 #if wxUSE_DRAG_AND_DROP
  22
  23 #include "wx/dataobj.h"
  24 #include "wx/cursor.h"
  25
  26 // ----------------------------------------------------------------------------
  27 // constants
  28 // ----------------------------------------------------------------------------
  29
  30 // result of wxDropSource::DoDragDrop() call
  31 enum wxDragResult
  32 {
  33     wxDragError,    // error prevented the d&d operation from completing
  34     wxDragNone,     // drag target didn't accept the data
  35     wxDragCopy,     // the data was successfully copied
  36     wxDragMove,     // the data was successfully moved (MSW only)
  37     wxDragCancel    // the operation was cancelled by user (not an error)
  38 };
  39
  40 inline WXDLLEXPORT bool wxIsDragResultOk(wxDragResult res)
  41 {
  42     return res == wxDragCopy || res == wxDragMove;
  43 }
  44
  45 // ----------------------------------------------------------------------------
  46 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  47 // to initiate a drag-and-drop operation
  48 // ----------------------------------------------------------------------------
  49
  50 class WXDLLEXPORT wxDropSourceBase
  51 {
  52 public:
  53     wxDropSourceBase(const wxCursor &cursorCopy = wxNullCursor,
  54                      const wxCursor &cursorMove = wxNullCursor,
  55                      const wxCursor &cursorStop = wxNullCursor)
  56         : m_cursorCopy(cursorCopy),
  57           m_cursorMove(cursorMove),
  58           m_cursorStop(cursorStop)
  59         { m_data = (wxDataObject *)NULL; }
  60     virtual ~wxDropSourceBase() { }
  61
  62     // set the data which is transfered by drag and drop
  63     void SetData(wxDataObject& data)
  64       { m_data = &data; }
  65
  66     wxDataObject *GetDataObject()
  67       { return m_data; }
  68
  69     // set the icon corresponding to given drag result
  70     void SetCursor(wxDragResult res, const wxCursor& cursor)
  71     {
  72         if ( res == wxDragCopy )
  73             m_cursorCopy = cursor;
  74         else if ( res == wxDragMove )
  75             m_cursorMove = cursor;
  76         else
  77             m_cursorStop = cursor;
  78     }
  79
  80     // start drag action, see enum wxDragResult for return value description
  81     //
  82     // if bAllowMove is TRUE, data can be moved, if not - only copied
  83     virtual wxDragResult DoDragDrop(bool bAllowMove = FALSE) = 0;
  84
  85     // override to give feedback depending on the current operation result
  86     // "effect" and return TRUE if you did something, FALSE to let the library
  87     // give the default feedback
  88     virtual bool GiveFeedback(wxDragResult WXUNUSED(effect)) { return FALSE; }
  89
  90 protected:
  91     const wxCursor& GetCursor(wxDragResult res) const
  92     {
  93         if ( res == wxDragCopy )
  94             return m_cursorCopy;
  95         else if ( res == wxDragMove )
  96             return m_cursorMove;
  97         else
  98             return m_cursorStop;
  99     }
 100
 101     wxDataObject *m_data;
 102
 103     // the cursors to use for feedback
 104     wxCursor      m_cursorCopy, m_cursorMove, m_cursorStop;
 105 };
 106
 107 // ----------------------------------------------------------------------------
 108 // wxDropTarget should be associated with a window if it wants to be able to
 109 // receive data via drag and drop.
 110 //
 111 // To use this class, you should derive from wxDropTarget and implement
 112 // OnData() pure virtual method. You may also wish to override OnDrop() if you
 113 // want to accept the data only inside some region of the window (this may
 114 // avoid having to copy the data to this application which happens only when
 115 // OnData() is called)
 116 // ----------------------------------------------------------------------------
 117
 118 class WXDLLEXPORT wxDropTargetBase
 119 {
 120 public:
 121     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
 122     // by wxDropTarget and deleted by it automatically. If you don't give it
 123     // here, you can use SetDataObject() later.
 124     wxDropTargetBase(wxDataObject *dataObject = (wxDataObject*)NULL)
 125         { m_dataObject = dataObject; }
 126     // dtor deletes our data object
 127     virtual ~wxDropTargetBase()
 128         { delete m_dataObject; }
 129
 130     // get/set the associated wxDataObject
 131     wxDataObject *GetDataObject() const
 132         { return m_dataObject; }
 133     void SetDataObject(wxDataObject *dataObject)
 134         { if (m_dataObject) delete m_dataObject;
 135     m_dataObject = dataObject; }
 136
 137     // these functions are called when data is moved over position (x, y) and
 138     // may return either wxDragCopy, wxDragMove or wxDragNone depending on
 139     // what would happen if the data were dropped here.
 140     //
 141     // the last parameter is what would happen by default and is determined by
 142     // the platform-specific logic (for example, under Windows it's wxDragCopy
 143     // if Ctrl key is pressed and wxDragMove otherwise) except that it will
 144     // always be wxDragNone if the carried data is in an unsupported format.
 145
 146     // called when the mouse enters the window (only once until OnLeave())
 147     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def)
 148         { return OnDragOver(x, y, def); }
 149
 150     // called when the mouse moves in the window - shouldn't take long to
 151     // execute or otherwise mouse movement would be too slow
 152     virtual wxDragResult OnDragOver(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y),
 153                                     wxDragResult def)
 154         { return def; }
 155
 156     // called when mouse leaves the window: might be used to remove the
 157     // feedback which was given in OnEnter()
 158     virtual void OnLeave() { }
 159
 160     // this function is called when data is dropped at position (x, y) - if it
 161     // returns TRUE, OnData() will be called immediately afterwards which will
 162     // allow to retrieve the data dropped.
 163     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 164
 165     // called after OnDrop() returns TRUE: you will usually just call
 166     // GetData() from here and, probably, also refresh something to update the
 167     // new data and, finally, return the code indicating how did the operation
 168     // complete (returning default value in case of success and wxDragError on
 169     // failure is usually ok)
 170     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def) = 0;
 171
 172     // may be called *only* from inside OnData() and will fill m_dataObject
 173     // with the data from the drop source if it returns TRUE
 174     virtual bool GetData() = 0;
 175
 176 protected:
 177     wxDataObject *m_dataObject;
 178 };
 179
 180 // ----------------------------------------------------------------------------
 181 // include platform dependent class declarations
 182 // ----------------------------------------------------------------------------
 183
 184 #if defined(__WXMSW__)
 185     #include "wx/msw/ole/dropsrc.h"
 186     #include "wx/msw/ole/droptgt.h"
 187 #elif defined(__WXMOTIF__)
 188     #include "wx/motif/dnd.h"
 189 #elif defined(__WXGTK__)
 190     #include "wx/gtk/dnd.h"
 191 #elif defined(__WXQT__)
 192     #include "wx/qt/dnd.h"
 193 #elif defined(__WXMAC__)
 194     #include "wx/mac/dnd.h"
 195 #elif defined(__WXPM__)
 196     #include "wx/os2/dnd.h"
 197 #elif defined(__WXSTUBS__)
 198     #include "wx/stubs/dnd.h"
 199 #endif
 200
 201 // ----------------------------------------------------------------------------
 202 // standard wxDropTarget implementations (implemented in common/dobjcmn.cpp)
 203 // ----------------------------------------------------------------------------
 204
 205 // A simple wxDropTarget derived class for text data: you only need to
 206 // override OnDropText() to get something working
 207 class WXDLLEXPORT wxTextDropTarget : public wxDropTarget
 208 {
 209 public:
 210     wxTextDropTarget();
 211
 212     virtual bool OnDropText(wxCoord x, wxCoord y, const wxString& text) = 0;
 213
 214     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 215 };
 216
 217 // A drop target which accepts files (dragged from File Manager or Explorer)
 218 class WXDLLEXPORT wxFileDropTarget : public wxDropTarget
 219 {
 220 public:
 221     wxFileDropTarget();
 222
 223     // parameters are the number of files and the array of file names
 224     virtual bool OnDropFiles(wxCoord x, wxCoord y,
 225                              const wxArrayString& filenames) = 0;
 226
 227     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 228 };
 229
 230 #endif // wxUSE_DRAG_AND_DROP
 231
 232 #endif // _WX_DND_H_BASE_