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) wxWidgets Team
   9 // Licence:     wxWindows licence
  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 // flags for wxDropSource::DoDragDrop()
  27 //
  28 // NB: wxDrag_CopyOnly must be 0 (== FALSE) and wxDrag_AllowMove must be 1
  29 //     (== TRUE) for compatibility with the old DoDragDrop(bool) method!
  30 enum
  31 {
  32     wxDrag_CopyOnly    = 0, // allow only copying
  33     wxDrag_AllowMove   = 1, // allow moving (copying is always allowed)
  34     wxDrag_DefaultMove = 3  // the default operation is move, not copy
  35 };
  36
  37 // result of wxDropSource::DoDragDrop() call
  38 enum wxDragResult
  39 {
  40     wxDragError,    // error prevented the d&d operation from completing
  41     wxDragNone,     // drag target didn't accept the data
  42     wxDragCopy,     // the data was successfully copied
  43     wxDragMove,     // the data was successfully moved (MSW only)
  44     wxDragLink,     // operation is a drag-link
  45     wxDragCancel    // the operation was cancelled by user (not an error)
  46 };
  47
  48 // return true if res indicates that something was done during a dnd operation,
  49 // i.e. is neither error nor none nor cancel
  50 WXDLLIMPEXP_CORE bool wxIsDragResultOk(wxDragResult res);
  51
  52 // ----------------------------------------------------------------------------
  53 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  54 // to initiate a drag-and-drop operation
  55 // ----------------------------------------------------------------------------
  56
  57 class WXDLLIMPEXP_CORE wxDropSourceBase
  58 {
  59 public:
  60     wxDropSourceBase(const wxCursor &cursorCopy = wxNullCursor,
  61                      const wxCursor &cursorMove = wxNullCursor,
  62                      const wxCursor &cursorStop = wxNullCursor)
  63         : m_cursorCopy(cursorCopy),
  64           m_cursorMove(cursorMove),
  65           m_cursorStop(cursorStop)
  66         { m_data = (wxDataObject *)NULL; }
  67     virtual ~wxDropSourceBase() { }
  68
  69     // set the data which is transfered by drag and drop
  70     void SetData(wxDataObject& data)
  71       { m_data = &data; }
  72
  73     wxDataObject *GetDataObject()
  74       { return m_data; }
  75
  76     // set the icon corresponding to given drag result
  77     void SetCursor(wxDragResult res, const wxCursor& cursor)
  78     {
  79         if ( res == wxDragCopy )
  80             m_cursorCopy = cursor;
  81         else if ( res == wxDragMove )
  82             m_cursorMove = cursor;
  83         else
  84             m_cursorStop = cursor;
  85     }
  86
  87     // start drag action, see enum wxDragResult for return value description
  88     //
  89     // if flags contains wxDrag_AllowMove, moving (and only copying) data is
  90     // allowed, if it contains wxDrag_DefaultMove (which includes the previous
  91     // flag), it is even the default operation
  92     virtual wxDragResult DoDragDrop(int flags = wxDrag_CopyOnly) = 0;
  93
  94     // override to give feedback depending on the current operation result
  95     // "effect" and return true if you did something, false to let the library
  96     // give the default feedback
  97     virtual bool GiveFeedback(wxDragResult WXUNUSED(effect)) { return false; }
  98
  99 protected:
 100     const wxCursor& GetCursor(wxDragResult res) const
 101     {
 102         if ( res == wxDragCopy )
 103             return m_cursorCopy;
 104         else if ( res == wxDragMove )
 105             return m_cursorMove;
 106         else
 107             return m_cursorStop;
 108     }
 109
 110     // the data we're dragging
 111     wxDataObject *m_data;
 112
 113     // the cursors to use for feedback
 114     wxCursor m_cursorCopy,
 115              m_cursorMove,
 116              m_cursorStop;
 117
 118     DECLARE_NO_COPY_CLASS(wxDropSourceBase)
 119 };
 120
 121 // ----------------------------------------------------------------------------
 122 // wxDropTarget should be associated with a window if it wants to be able to
 123 // receive data via drag and drop.
 124 //
 125 // To use this class, you should derive from wxDropTarget and implement
 126 // OnData() pure virtual method. You may also wish to override OnDrop() if you
 127 // want to accept the data only inside some region of the window (this may
 128 // avoid having to copy the data to this application which happens only when
 129 // OnData() is called)
 130 // ----------------------------------------------------------------------------
 131
 132 class WXDLLIMPEXP_CORE wxDropTargetBase
 133 {
 134 public:
 135     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
 136     // by wxDropTarget and deleted by it automatically. If you don't give it
 137     // here, you can use SetDataObject() later.
 138     wxDropTargetBase(wxDataObject *dataObject = (wxDataObject*)NULL)
 139         { m_dataObject = dataObject; m_defaultAction = wxDragNone; }
 140     // dtor deletes our data object
 141     virtual ~wxDropTargetBase()
 142         { delete m_dataObject; }
 143
 144     // get/set the associated wxDataObject
 145     wxDataObject *GetDataObject() const
 146         { return m_dataObject; }
 147     void SetDataObject(wxDataObject *dataObject)
 148         { if (m_dataObject) delete m_dataObject;
 149     m_dataObject = dataObject; }
 150
 151     // these functions are called when data is moved over position (x, y) and
 152     // may return either wxDragCopy, wxDragMove or wxDragNone depending on
 153     // what would happen if the data were dropped here.
 154     //
 155     // the last parameter is what would happen by default and is determined by
 156     // the platform-specific logic (for example, under Windows it's wxDragCopy
 157     // if Ctrl key is pressed and wxDragMove otherwise) except that it will
 158     // always be wxDragNone if the carried data is in an unsupported format.
 159
 160     // called when the mouse enters the window (only once until OnLeave())
 161     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def)
 162         { return OnDragOver(x, y, def); }
 163
 164     // called when the mouse moves in the window - shouldn't take long to
 165     // execute or otherwise mouse movement would be too slow
 166     virtual wxDragResult OnDragOver(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y),
 167                                     wxDragResult def)
 168         { return def; }
 169
 170     // called when mouse leaves the window: might be used to remove the
 171     // feedback which was given in OnEnter()
 172     virtual void OnLeave() { }
 173
 174     // this function is called when data is dropped at position (x, y) - if it
 175     // returns true, OnData() will be called immediately afterwards which will
 176     // allow to retrieve the data dropped.
 177     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 178
 179     // called after OnDrop() returns TRUE: you will usually just call
 180     // GetData() from here and, probably, also refresh something to update the
 181     // new data and, finally, return the code indicating how did the operation
 182     // complete (returning default value in case of success and wxDragError on
 183     // failure is usually ok)
 184     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def) = 0;
 185
 186     // may be called *only* from inside OnData() and will fill m_dataObject
 187     // with the data from the drop source if it returns true
 188     virtual bool GetData() = 0;
 189
 190     // sets the default action for drag and drop:
 191     // use wxDragMove or wxDragCopy to set deafult action to move or copy
 192     // and use wxDragNone (default) to set default action specified by
 193     // initialization of draging (see wxDropSourceBase::DoDragDrop())
 194     void SetDefaultAction(wxDragResult action)
 195         { m_defaultAction = action; }
 196
 197     // returns default action for drag and drop or
 198     // wxDragNone if this not specified
 199     wxDragResult GetDefaultAction()
 200         { return m_defaultAction; }
 201
 202 protected:
 203     wxDataObject *m_dataObject;
 204     wxDragResult m_defaultAction;
 205
 206     DECLARE_NO_COPY_CLASS(wxDropTargetBase)
 207 };
 208
 209 // ----------------------------------------------------------------------------
 210 // include platform dependent class declarations
 211 // ----------------------------------------------------------------------------
 212
 213 #if defined(__WXMSW__)
 214     #include "wx/msw/ole/dropsrc.h"
 215     #include "wx/msw/ole/droptgt.h"
 216 #elif defined(__WXMOTIF__)
 217     #include "wx/motif/dnd.h"
 218 #elif defined(__WXX11__)
 219     #include "wx/x11/dnd.h"
 220 #elif defined(__WXGTK20__)
 221     #include "wx/gtk/dnd.h"
 222 #elif defined(__WXGTK__)
 223     #include "wx/gtk1/dnd.h"
 224 #elif defined(__WXMAC__)
 225     #include "wx/mac/dnd.h"
 226 #elif defined(__WXPM__)
 227     #include "wx/os2/dnd.h"
 228 #endif
 229
 230 // ----------------------------------------------------------------------------
 231 // standard wxDropTarget implementations (implemented in common/dobjcmn.cpp)
 232 // ----------------------------------------------------------------------------
 233
 234 // A simple wxDropTarget derived class for text data: you only need to
 235 // override OnDropText() to get something working
 236 class WXDLLIMPEXP_CORE wxTextDropTarget : public wxDropTarget
 237 {
 238 public:
 239     wxTextDropTarget();
 240
 241     virtual bool OnDropText(wxCoord x, wxCoord y, const wxString& text) = 0;
 242
 243     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 244
 245 private:
 246     DECLARE_NO_COPY_CLASS(wxTextDropTarget)
 247 };
 248
 249 // A drop target which accepts files (dragged from File Manager or Explorer)
 250 class WXDLLIMPEXP_CORE wxFileDropTarget : public wxDropTarget
 251 {
 252 public:
 253     wxFileDropTarget();
 254
 255     // parameters are the number of files and the array of file names
 256     virtual bool OnDropFiles(wxCoord x, wxCoord y,
 257                              const wxArrayString& filenames) = 0;
 258
 259     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 260
 261 private:
 262     DECLARE_NO_COPY_CLASS(wxFileDropTarget)
 263 };
 264
 265 #endif // wxUSE_DRAG_AND_DROP
 266
 267 #endif // _WX_DND_H_BASE_