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