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 // Copyright:   (c) wxWidgets Team
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef _WX_DND_H_BASE_
  12 #define _WX_DND_H_BASE_
  13
  14 #include "wx/defs.h"
  15
  16 #if wxUSE_DRAG_AND_DROP
  17
  18 #include "wx/dataobj.h"
  19 #include "wx/cursor.h"
  20
  21 // ----------------------------------------------------------------------------
  22 // constants
  23 // ----------------------------------------------------------------------------
  24
  25 // flags for wxDropSource::DoDragDrop()
  26 //
  27 // NB: wxDrag_CopyOnly must be 0 (== FALSE) and wxDrag_AllowMove must be 1
  28 //     (== TRUE) for compatibility with the old DoDragDrop(bool) method!
  29 enum
  30 {
  31     wxDrag_CopyOnly    = 0, // allow only copying
  32     wxDrag_AllowMove   = 1, // allow moving (copying is always allowed)
  33     wxDrag_DefaultMove = 3  // the default operation is move, not copy
  34 };
  35
  36 // result of wxDropSource::DoDragDrop() call
  37 enum wxDragResult
  38 {
  39     wxDragError,    // error prevented the d&d operation from completing
  40     wxDragNone,     // drag target didn't accept the data
  41     wxDragCopy,     // the data was successfully copied
  42     wxDragMove,     // the data was successfully moved (MSW only)
  43     wxDragLink,     // operation is a drag-link
  44     wxDragCancel    // the operation was cancelled by user (not an error)
  45 };
  46
  47 // return true if res indicates that something was done during a dnd operation,
  48 // i.e. is neither error nor none nor cancel
  49 WXDLLIMPEXP_CORE bool wxIsDragResultOk(wxDragResult res);
  50
  51 // ----------------------------------------------------------------------------
  52 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  53 // to initiate a drag-and-drop operation
  54 // ----------------------------------------------------------------------------
  55
  56 class WXDLLIMPEXP_CORE wxDropSourceBase
  57 {
  58 public:
  59     wxDropSourceBase(const wxCursor &cursorCopy = wxNullCursor,
  60                      const wxCursor &cursorMove = wxNullCursor,
  61                      const wxCursor &cursorStop = wxNullCursor)
  62         : m_cursorCopy(cursorCopy),
  63           m_cursorMove(cursorMove),
  64           m_cursorStop(cursorStop)
  65         { m_data = NULL; }
  66     virtual ~wxDropSourceBase() { }
  67
  68     // set the data which is transferred by drag and drop
  69     void SetData(wxDataObject& data)
  70       { m_data = &data; }
  71
  72     wxDataObject *GetDataObject()
  73       { return m_data; }
  74
  75     // set the icon corresponding to given drag result
  76     void SetCursor(wxDragResult res, const wxCursor& cursor)
  77     {
  78         if ( res == wxDragCopy )
  79             m_cursorCopy = cursor;
  80         else if ( res == wxDragMove )
  81             m_cursorMove = cursor;
  82         else
  83             m_cursorStop = cursor;
  84     }
  85
  86     // start drag action, see enum wxDragResult for return value description
  87     //
  88     // if flags contains wxDrag_AllowMove, moving (and only copying) data is
  89     // allowed, if it contains wxDrag_DefaultMove (which includes the previous
  90     // flag), it is even the default operation
  91     virtual wxDragResult DoDragDrop(int flags = wxDrag_CopyOnly) = 0;
  92
  93     // override to give feedback depending on the current operation result
  94     // "effect" and return true if you did something, false to let the library
  95     // give the default feedback
  96     virtual bool GiveFeedback(wxDragResult WXUNUSED(effect)) { return false; }
  97
  98 protected:
  99     const wxCursor& GetCursor(wxDragResult res) const
 100     {
 101         if ( res == wxDragCopy )
 102             return m_cursorCopy;
 103         else if ( res == wxDragMove )
 104             return m_cursorMove;
 105         else
 106             return m_cursorStop;
 107     }
 108
 109     // the data we're dragging
 110     wxDataObject *m_data;
 111
 112     // the cursors to use for feedback
 113     wxCursor m_cursorCopy,
 114              m_cursorMove,
 115              m_cursorStop;
 116
 117     wxDECLARE_NO_COPY_CLASS(wxDropSourceBase);
 118 };
 119
 120 // ----------------------------------------------------------------------------
 121 // wxDropTarget should be associated with a window if it wants to be able to
 122 // receive data via drag and drop.
 123 //
 124 // To use this class, you should derive from wxDropTarget and implement
 125 // OnData() pure virtual method. You may also wish to override OnDrop() if you
 126 // want to accept the data only inside some region of the window (this may
 127 // avoid having to copy the data to this application which happens only when
 128 // OnData() is called)
 129 // ----------------------------------------------------------------------------
 130
 131 class WXDLLIMPEXP_CORE wxDropTargetBase
 132 {
 133 public:
 134     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
 135     // by wxDropTarget and deleted by it automatically. If you don't give it
 136     // here, you can use SetDataObject() later.
 137     wxDropTargetBase(wxDataObject *dataObject = NULL)
 138         { m_dataObject = dataObject; m_defaultAction = wxDragNone; }
 139     // dtor deletes our data object
 140     virtual ~wxDropTargetBase()
 141         { delete m_dataObject; }
 142
 143     // get/set the associated wxDataObject
 144     wxDataObject *GetDataObject() const
 145         { return m_dataObject; }
 146     void SetDataObject(wxDataObject *dataObject)
 147         { if (m_dataObject) delete m_dataObject;
 148     m_dataObject = dataObject; }
 149
 150     // these functions are called when data is moved over position (x, y) and
 151     // may return either wxDragCopy, wxDragMove or wxDragNone depending on
 152     // what would happen if the data were dropped here.
 153     //
 154     // the last parameter is what would happen by default and is determined by
 155     // the platform-specific logic (for example, under Windows it's wxDragCopy
 156     // if Ctrl key is pressed and wxDragMove otherwise) except that it will
 157     // always be wxDragNone if the carried data is in an unsupported format.
 158
 159     // called when the mouse enters the window (only once until OnLeave())
 160     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def)
 161         { return OnDragOver(x, y, def); }
 162
 163     // called when the mouse moves in the window - shouldn't take long to
 164     // execute or otherwise mouse movement would be too slow
 165     virtual wxDragResult OnDragOver(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y),
 166                                     wxDragResult def)
 167         { return def; }
 168
 169     // called when mouse leaves the window: might be used to remove the
 170     // feedback which was given in OnEnter()
 171     virtual void OnLeave() { }
 172
 173     // this function is called when data is dropped at position (x, y) - if it
 174     // returns true, OnData() will be called immediately afterwards which will
 175     // allow to retrieve the data dropped.
 176     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 177
 178     // called after OnDrop() returns TRUE: you will usually just call
 179     // GetData() from here and, probably, also refresh something to update the
 180     // new data and, finally, return the code indicating how did the operation
 181     // complete (returning default value in case of success and wxDragError on
 182     // failure is usually ok)
 183     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def) = 0;
 184
 185     // may be called *only* from inside OnData() and will fill m_dataObject
 186     // with the data from the drop source if it returns true
 187     virtual bool GetData() = 0;
 188
 189     // sets the default action for drag and drop:
 190     // use wxDragMove or wxDragCopy to set deafult action to move or copy
 191     // and use wxDragNone (default) to set default action specified by
 192     // initialization of draging (see wxDropSourceBase::DoDragDrop())
 193     void SetDefaultAction(wxDragResult action)
 194         { m_defaultAction = action; }
 195
 196     // returns default action for drag and drop or
 197     // wxDragNone if this not specified
 198     wxDragResult GetDefaultAction()
 199         { return m_defaultAction; }
 200
 201 protected:
 202     wxDataObject *m_dataObject;
 203     wxDragResult m_defaultAction;
 204
 205     wxDECLARE_NO_COPY_CLASS(wxDropTargetBase);
 206 };
 207
 208 // ----------------------------------------------------------------------------
 209 // include platform dependent class declarations
 210 // ----------------------------------------------------------------------------
 211
 212 #if defined(__WXMSW__)
 213     #include "wx/msw/ole/dropsrc.h"
 214     #include "wx/msw/ole/droptgt.h"
 215 #elif defined(__WXMOTIF__)
 216     #include "wx/motif/dnd.h"
 217 #elif defined(__WXX11__)
 218     #include "wx/x11/dnd.h"
 219 #elif defined(__WXGTK20__)
 220     #include "wx/gtk/dnd.h"
 221 #elif defined(__WXGTK__)
 222     #include "wx/gtk1/dnd.h"
 223 #elif defined(__WXMAC__)
 224     #include "wx/osx/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 WXDLLIMPEXP_CORE 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     wxDECLARE_NO_COPY_CLASS(wxTextDropTarget);
 246 };
 247
 248 // A drop target which accepts files (dragged from File Manager or Explorer)
 249 class WXDLLIMPEXP_CORE 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     wxDECLARE_NO_COPY_CLASS(wxFileDropTarget);
 262 };
 263
 264 #endif // wxUSE_DRAG_AND_DROP
 265
 266 #endif // _WX_DND_H_BASE_