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 inline WXDLLEXPORT bool wxIsDragResultOk(wxDragResult res)
  49 {
  50     return res == wxDragCopy || res == wxDragMove || res == wxDragLink;
  51 }
  52
  53 // ----------------------------------------------------------------------------
  54 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  55 // to initiate a drag-and-drop operation
  56 // ----------------------------------------------------------------------------
  57
  58 class WXDLLEXPORT wxDropSourceBase
  59 {
  60 public:
  61     wxDropSourceBase(const wxCursor &cursorCopy = wxNullCursor,
  62                      const wxCursor &cursorMove = wxNullCursor,
  63                      const wxCursor &cursorStop = wxNullCursor)
  64         : m_cursorCopy(cursorCopy),
  65           m_cursorMove(cursorMove),
  66           m_cursorStop(cursorStop)
  67         { m_data = (wxDataObject *)NULL; }
  68     virtual ~wxDropSourceBase() { }
  69
  70     // set the data which is transfered by drag and drop
  71     void SetData(wxDataObject& data)
  72       { m_data = &data; }
  73
  74     wxDataObject *GetDataObject()
  75       { return m_data; }
  76
  77     // set the icon corresponding to given drag result
  78     void SetCursor(wxDragResult res, const wxCursor& cursor)
  79     {
  80         if ( res == wxDragCopy )
  81             m_cursorCopy = cursor;
  82         else if ( res == wxDragMove )
  83             m_cursorMove = cursor;
  84         else
  85             m_cursorStop = cursor;
  86     }
  87
  88     // start drag action, see enum wxDragResult for return value description
  89     //
  90     // if flags contains wxDrag_AllowMove, moving (and only copying) data is
  91     // allowed, if it contains wxDrag_DefaultMove (which includes the previous
  92     // flag), it is even the default operation
  93     virtual wxDragResult DoDragDrop(int flags = wxDrag_CopyOnly) = 0;
  94
  95     // override to give feedback depending on the current operation result
  96     // "effect" and return true if you did something, false to let the library
  97     // give the default feedback
  98     virtual bool GiveFeedback(wxDragResult WXUNUSED(effect)) { return false; }
  99
 100 protected:
 101     const wxCursor& GetCursor(wxDragResult res) const
 102     {
 103         if ( res == wxDragCopy )
 104             return m_cursorCopy;
 105         else if ( res == wxDragMove )
 106             return m_cursorMove;
 107         else
 108             return m_cursorStop;
 109     }
 110
 111     // the data we're dragging
 112     wxDataObject *m_data;
 113
 114     // the cursors to use for feedback
 115     wxCursor m_cursorCopy,
 116              m_cursorMove,
 117              m_cursorStop;
 118
 119     DECLARE_NO_COPY_CLASS(wxDropSourceBase)
 120 };
 121
 122 // ----------------------------------------------------------------------------
 123 // wxDropTarget should be associated with a window if it wants to be able to
 124 // receive data via drag and drop.
 125 //
 126 // To use this class, you should derive from wxDropTarget and implement
 127 // OnData() pure virtual method. You may also wish to override OnDrop() if you
 128 // want to accept the data only inside some region of the window (this may
 129 // avoid having to copy the data to this application which happens only when
 130 // OnData() is called)
 131 // ----------------------------------------------------------------------------
 132
 133 class WXDLLEXPORT wxDropTargetBase
 134 {
 135 public:
 136     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
 137     // by wxDropTarget and deleted by it automatically. If you don't give it
 138     // here, you can use SetDataObject() later.
 139     wxDropTargetBase(wxDataObject *dataObject = (wxDataObject*)NULL)
 140         { m_dataObject = dataObject; m_defaultAction = wxDragNone; }
 141     // dtor deletes our data object
 142     virtual ~wxDropTargetBase()
 143         { delete m_dataObject; }
 144
 145     // get/set the associated wxDataObject
 146     wxDataObject *GetDataObject() const
 147         { return m_dataObject; }
 148     void SetDataObject(wxDataObject *dataObject)
 149         { if (m_dataObject) delete m_dataObject;
 150     m_dataObject = dataObject; }
 151
 152     // these functions are called when data is moved over position (x, y) and
 153     // may return either wxDragCopy, wxDragMove or wxDragNone depending on
 154     // what would happen if the data were dropped here.
 155     //
 156     // the last parameter is what would happen by default and is determined by
 157     // the platform-specific logic (for example, under Windows it's wxDragCopy
 158     // if Ctrl key is pressed and wxDragMove otherwise) except that it will
 159     // always be wxDragNone if the carried data is in an unsupported format.
 160
 161     // called when the mouse enters the window (only once until OnLeave())
 162     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def)
 163         { return OnDragOver(x, y, def); }
 164
 165     // called when the mouse moves in the window - shouldn't take long to
 166     // execute or otherwise mouse movement would be too slow
 167     virtual wxDragResult OnDragOver(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y),
 168                                     wxDragResult def)
 169         { return def; }
 170
 171     // called when mouse leaves the window: might be used to remove the
 172     // feedback which was given in OnEnter()
 173     virtual void OnLeave() { }
 174
 175     // this function is called when data is dropped at position (x, y) - if it
 176     // returns true, OnData() will be called immediately afterwards which will
 177     // allow to retrieve the data dropped.
 178     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 179
 180     // called after OnDrop() returns TRUE: you will usually just call
 181     // GetData() from here and, probably, also refresh something to update the
 182     // new data and, finally, return the code indicating how did the operation
 183     // complete (returning default value in case of success and wxDragError on
 184     // failure is usually ok)
 185     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def) = 0;
 186
 187     // may be called *only* from inside OnData() and will fill m_dataObject
 188     // with the data from the drop source if it returns true
 189     virtual bool GetData() = 0;
 190
 191     // sets the default action for drag and drop:
 192     // use wxDragMove or wxDragCopy to set deafult action to move or copy
 193     // and use wxDragNone (default) to set default action specified by
 194     // initialization of draging (see wxDropSourceBase::DoDragDrop())
 195     void SetDefaultAction(wxDragResult action)
 196         { m_defaultAction = action; }
 197
 198     // returns default action for drag and drop or
 199     // wxDragNone if this not specified
 200     wxDragResult GetDefaultAction()
 201         { return m_defaultAction; }
 202
 203 protected:
 204     wxDataObject *m_dataObject;
 205     wxDragResult m_defaultAction;
 206
 207     DECLARE_NO_COPY_CLASS(wxDropTargetBase)
 208 };
 209
 210 // ----------------------------------------------------------------------------
 211 // include platform dependent class declarations
 212 // ----------------------------------------------------------------------------
 213
 214 #if defined(__WXMSW__)
 215     #include "wx/msw/ole/dropsrc.h"
 216     #include "wx/msw/ole/droptgt.h"
 217 #elif defined(__WXMOTIF__)
 218     #include "wx/motif/dnd.h"
 219 #elif defined(__WXX11__)
 220     #include "wx/x11/dnd.h"
 221 #elif defined(__WXGTK__)
 222     #include "wx/gtk/dnd.h"
 223 #elif defined(__WXMAC__)
 224     #include "wx/mac/dnd.h"
 225 #elif defined(__WXPM__)
 226     #include "wx/os2/dnd.h"
 227 #endif
 228
 229 // ----------------------------------------------------------------------------
 230 // standard wxDropTarget implementations (implemented in common/dobjcmn.cpp)
 231 // ----------------------------------------------------------------------------
 232
 233 // A simple wxDropTarget derived class for text data: you only need to
 234 // override OnDropText() to get something working
 235 class WXDLLEXPORT wxTextDropTarget : public wxDropTarget
 236 {
 237 public:
 238     wxTextDropTarget();
 239
 240     virtual bool OnDropText(wxCoord x, wxCoord y, const wxString& text) = 0;
 241
 242     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 243
 244 private:
 245     DECLARE_NO_COPY_CLASS(wxTextDropTarget)
 246 };
 247
 248 // A drop target which accepts files (dragged from File Manager or Explorer)
 249 class WXDLLEXPORT wxFileDropTarget : public wxDropTarget
 250 {
 251 public:
 252     wxFileDropTarget();
 253
 254     // parameters are the number of files and the array of file names
 255     virtual bool OnDropFiles(wxCoord x, wxCoord y,
 256                              const wxArrayString& filenames) = 0;
 257
 258     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 259
 260 private:
 261     DECLARE_NO_COPY_CLASS(wxFileDropTarget)
 262 };
 263
 264 #endif // wxUSE_DRAG_AND_DROP
 265
 266 #endif // _WX_DND_H_BASE_