ui/aura/client/drag_drop_delegate.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_AURA_CLIENT_DRAG_DROP_DELEGATE_H_
   6 #define UI_AURA_CLIENT_DRAG_DROP_DELEGATE_H_
   7
   8 #include "ui/aura/aura_export.h"
   9
  10 namespace ui {
  11 class DropTargetEvent;
  12 }
  13
  14 namespace aura {
  15 class Window;
  16 namespace client {
  17
  18 // Delegate interface for drag and drop actions on aura::Window.
  19 class AURA_EXPORT DragDropDelegate {
  20  public:
  21   // OnDragEntered is invoked when the mouse enters this window during a drag &
  22   // drop session. This is immediately followed by an invocation of
  23   // OnDragUpdated, and eventually one of OnDragExited or OnPerformDrop.
  24   virtual void OnDragEntered(const ui::DropTargetEvent& event) = 0;
  25
  26   // Invoked during a drag and drop session while the mouse is over the window.
  27   // This should return a bitmask of the DragDropTypes::DragOperation supported
  28   // based on the location of the event. Return 0 to indicate the drop should
  29   // not be accepted.
  30   virtual int OnDragUpdated(const ui::DropTargetEvent& event) = 0;
  31
  32   // Invoked during a drag and drop session when the mouse exits the window, or
  33   // when the drag session was canceled and the mouse was over the window.
  34   virtual void OnDragExited() = 0;
  35
  36   // Invoked during a drag and drop session when OnDragUpdated returns a valid
  37   // operation and the user release the mouse.
  38   virtual int OnPerformDrop(const ui::DropTargetEvent& event) = 0;
  39
  40  protected:
  41   virtual ~DragDropDelegate() {}
  42 };
  43
  44 AURA_EXPORT void SetDragDropDelegate(Window* window,
  45                                      DragDropDelegate* delegate);
  46 AURA_EXPORT DragDropDelegate* GetDragDropDelegate(Window* window);
  47
  48 }  // namespace client
  49 }  // namespace aura
  50
  51 #endif  // UI_AURA_CLIENT_DRAG_DROP_DELEGATE_H_