ui/wm/public/activation_change_observer.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_WM_PUBLIC_ACTIVATION_CHANGE_OBSERVER_H_
   6 #define UI_WM_PUBLIC_ACTIVATION_CHANGE_OBSERVER_H_
   7
   8 #include "ui/aura/aura_export.h"
   9
  10 namespace aura {
  11 class Window;
  12
  13 namespace client {
  14
  15 class AURA_EXPORT ActivationChangeObserver {
  16  public:
  17   // The reason or cause of a window activation change.
  18   enum class ActivationReason {
  19     // When a window is activated due to a call to the ActivationClient API.
  20     ACTIVATION_CLIENT,
  21     // When a user clicks or taps a window in the 2-dimensional screen space.
  22     INPUT_EVENT,
  23     // When a new window is activated as a side effect of a window
  24     // disposition changing.
  25     WINDOW_DISPOSITION_CHANGED,
  26   };
  27
  28   // Called when |gained_active| gains focus, or there is no active window
  29   // (|gained_active| is NULL in this case.) |lost_active| refers to the
  30   // previous active window or NULL if there was no previously active
  31   // window. |reason| specifies the cause of the activation change.
  32   virtual void OnWindowActivated(ActivationReason reason,
  33                                  Window* gained_active,
  34                                  Window* lost_active) = 0;
  35
  36   // Called when during window activation the currently active window is
  37   // selected for activation. This can happen when a window requested for
  38   // activation cannot be activated because a system modal window is active.
  39   virtual void OnAttemptToReactivateWindow(aura::Window* request_active,
  40                                            aura::Window* actual_active) {}
  41
  42  protected:
  43   virtual ~ActivationChangeObserver() {}
  44 };
  45
  46 // Gets/Sets the ActivationChangeObserver for a specific window. This observer
  47 // is notified after the ActivationClient notifies all registered observers.
  48 AURA_EXPORT void SetActivationChangeObserver(
  49     Window* window,
  50     ActivationChangeObserver* observer);
  51 AURA_EXPORT ActivationChangeObserver* GetActivationChangeObserver(
  52     Window* window);
  53
  54 }  // namespace client
  55 }  // namespace aura
  56
  57 #endif  // UI_WM_PUBLIC_ACTIVATION_CHANGE_OBSERVER_H_