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 // flags for wxDropSource::DoDragDrop()
  31 //
  32 // NB: wxDrag_CopyOnly must be 0 (== FALSE) and wxDrag_AllowMove must be 1
  33 //     (== TRUE) for compatibility with the old DoDragDrop(bool) method!
  34 enum
  35 {
  36     wxDrag_CopyOnly    = 0, // allow only copying
  37     wxDrag_AllowMove   = 1, // allow moving (copying is always allowed)
  38     wxDrag_DefaultMove = 3  // the default operation is move, not copy
  39 };
  40
  41 // result of wxDropSource::DoDragDrop() call
  42 enum wxDragResult
  43 {
  44     wxDragError,    // error prevented the d&d operation from completing
  45     wxDragNone,     // drag target didn't accept the data
  46     wxDragCopy,     // the data was successfully copied
  47     wxDragMove,     // the data was successfully moved (MSW only)
  48     wxDragLink,     // operation is a drag-link
  49     wxDragCancel    // the operation was cancelled by user (not an error)
  50 };
  51
  52 inline WXDLLEXPORT bool wxIsDragResultOk(wxDragResult res)
  53 {
  54     return res == wxDragCopy || res == wxDragMove || res == wxDragLink;
  55 }
  56
  57 // ----------------------------------------------------------------------------
  58 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  59 // to initiate a drag-and-drop operation
  60 // ----------------------------------------------------------------------------
  61
  62 class WXDLLEXPORT wxDropSourceBase
  63 {
  64 public:
  65     wxDropSourceBase(const wxCursor &cursorCopy = wxNullCursor,
  66                      const wxCursor &cursorMove = wxNullCursor,
  67                      const wxCursor &cursorStop = wxNullCursor)
  68         : m_cursorCopy(cursorCopy),
  69           m_cursorMove(cursorMove),
  70           m_cursorStop(cursorStop)
  71         { m_data = (wxDataObject *)NULL; }
  72     virtual ~wxDropSourceBase() { }
  73
  74     // set the data which is transfered by drag and drop
  75     void SetData(wxDataObject& data)
  76       { m_data = &data; }
  77
  78     wxDataObject *GetDataObject()
  79       { return m_data; }
  80
  81     // set the icon corresponding to given drag result
  82     void SetCursor(wxDragResult res, const wxCursor& cursor)
  83     {
  84         if ( res == wxDragCopy )
  85             m_cursorCopy = cursor;
  86         else if ( res == wxDragMove )
  87             m_cursorMove = cursor;
  88         else
  89             m_cursorStop = cursor;
  90     }
  91
  92     // start drag action, see enum wxDragResult for return value description
  93     //
  94     // if flags contains wxDrag_AllowMove, moving (and only copying) data is
  95     // allowed, if it contains wxDrag_DefaultMove (which includes the previous
  96     // flag), it is even the default operation
  97     virtual wxDragResult DoDragDrop(int flags = wxDrag_CopyOnly) = 0;
  98
  99     // override to give feedback depending on the current operation result
 100     // "effect" and return TRUE if you did something, FALSE to let the library
 101     // give the default feedback
 102     virtual bool GiveFeedback(wxDragResult WXUNUSED(effect)) { return FALSE; }
 103
 104 protected:
 105     const wxCursor& GetCursor(wxDragResult res) const
 106     {
 107         if ( res == wxDragCopy )
 108             return m_cursorCopy;
 109         else if ( res == wxDragMove )
 110             return m_cursorMove;
 111         else
 112             return m_cursorStop;
 113     }
 114
 115     // the data we're dragging
 116     wxDataObject *m_data;
 117
 118     // the cursors to use for feedback
 119     wxCursor m_cursorCopy,
 120              m_cursorMove,
 121              m_cursorStop;
 122 };
 123
 124 // ----------------------------------------------------------------------------
 125 // wxDropTarget should be associated with a window if it wants to be able to
 126 // receive data via drag and drop.
 127 //
 128 // To use this class, you should derive from wxDropTarget and implement
 129 // OnData() pure virtual method. You may also wish to override OnDrop() if you
 130 // want to accept the data only inside some region of the window (this may
 131 // avoid having to copy the data to this application which happens only when
 132 // OnData() is called)
 133 // ----------------------------------------------------------------------------
 134
 135 class WXDLLEXPORT wxDropTargetBase
 136 {
 137 public:
 138     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
 139     // by wxDropTarget and deleted by it automatically. If you don't give it
 140     // here, you can use SetDataObject() later.
 141     wxDropTargetBase(wxDataObject *dataObject = (wxDataObject*)NULL)
 142         { m_dataObject = dataObject; }
 143     // dtor deletes our data object
 144     virtual ~wxDropTargetBase()
 145         { delete m_dataObject; }
 146
 147     // get/set the associated wxDataObject
 148     wxDataObject *GetDataObject() const
 149         { return m_dataObject; }
 150     void SetDataObject(wxDataObject *dataObject)
 151         { if (m_dataObject) delete m_dataObject;
 152     m_dataObject = dataObject; }
 153
 154     // these functions are called when data is moved over position (x, y) and
 155     // may return either wxDragCopy, wxDragMove or wxDragNone depending on
 156     // what would happen if the data were dropped here.
 157     //
 158     // the last parameter is what would happen by default and is determined by
 159     // the platform-specific logic (for example, under Windows it's wxDragCopy
 160     // if Ctrl key is pressed and wxDragMove otherwise) except that it will
 161     // always be wxDragNone if the carried data is in an unsupported format.
 162
 163     // called when the mouse enters the window (only once until OnLeave())
 164     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def)
 165         { return OnDragOver(x, y, def); }
 166
 167     // called when the mouse moves in the window - shouldn't take long to
 168     // execute or otherwise mouse movement would be too slow
 169     virtual wxDragResult OnDragOver(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y),
 170                                     wxDragResult def)
 171         { return def; }
 172
 173     // called when mouse leaves the window: might be used to remove the
 174     // feedback which was given in OnEnter()
 175     virtual void OnLeave() { }
 176
 177     // this function is called when data is dropped at position (x, y) - if it
 178     // returns TRUE, OnData() will be called immediately afterwards which will
 179     // allow to retrieve the data dropped.
 180     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 181
 182     // called after OnDrop() returns TRUE: you will usually just call
 183     // GetData() from here and, probably, also refresh something to update the
 184     // new data and, finally, return the code indicating how did the operation
 185     // complete (returning default value in case of success and wxDragError on
 186     // failure is usually ok)
 187     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def) = 0;
 188
 189     // may be called *only* from inside OnData() and will fill m_dataObject
 190     // with the data from the drop source if it returns TRUE
 191     virtual bool GetData() = 0;
 192
 193 protected:
 194     wxDataObject *m_dataObject;
 195 };
 196
 197 // ----------------------------------------------------------------------------
 198 // include platform dependent class declarations
 199 // ----------------------------------------------------------------------------
 200
 201 #if defined(__WXMSW__)
 202     #include "wx/msw/ole/dropsrc.h"
 203     #include "wx/msw/ole/droptgt.h"
 204 #elif defined(__WXMOTIF__)
 205     #include "wx/motif/dnd.h"
 206 #elif defined(__WXX11__)
 207     #include "wx/x11/dnd.h"
 208 #elif defined(__WXGTK__)
 209     #include "wx/gtk/dnd.h"
 210 #elif defined(__WXMAC__)
 211     #include "wx/mac/dnd.h"
 212 #elif defined(__WXPM__)
 213     #include "wx/os2/dnd.h"
 214 #elif defined(__WXSTUBS__)
 215     #include "wx/stubs/dnd.h"
 216 #endif
 217
 218 // ----------------------------------------------------------------------------
 219 // standard wxDropTarget implementations (implemented in common/dobjcmn.cpp)
 220 // ----------------------------------------------------------------------------
 221
 222 // A simple wxDropTarget derived class for text data: you only need to
 223 // override OnDropText() to get something working
 224 class WXDLLEXPORT wxTextDropTarget : public wxDropTarget
 225 {
 226 public:
 227     wxTextDropTarget();
 228
 229     virtual bool OnDropText(wxCoord x, wxCoord y, const wxString& text) = 0;
 230
 231     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 232 };
 233
 234 // A drop target which accepts files (dragged from File Manager or Explorer)
 235 class WXDLLEXPORT wxFileDropTarget : public wxDropTarget
 236 {
 237 public:
 238     wxFileDropTarget();
 239
 240     // parameters are the number of files and the array of file names
 241     virtual bool OnDropFiles(wxCoord x, wxCoord y,
 242                              const wxArrayString& filenames) = 0;
 243
 244     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 245 };
 246
 247 #endif // wxUSE_DRAG_AND_DROP
 248
 249 #endif // _WX_DND_H_BASE_