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