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