ui/views/focus/widget_focus_manager.h

   1 // Copyright (c) 2011 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_VIEWS_FOCUS_WIDGET_FOCUS_MANAGER_H_
   6 #define UI_VIEWS_FOCUS_WIDGET_FOCUS_MANAGER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/observer_list.h"
  10 #include "ui/gfx/native_widget_types.h"
  11 #include "ui/views/views_export.h"
  12
  13 namespace base {
  14 template <typename T> struct DefaultSingletonTraits;
  15 }
  16
  17 namespace views {
  18
  19 // This interface should be implemented by classes that want to be notified when
  20 // the native focus is about to change.  Listeners implementing this interface
  21 // will be invoked for all native focus changes across the entire Chrome
  22 // application.  FocusChangeListeners are only called for changes within the
  23 // children of a single top-level native-view.
  24 class WidgetFocusChangeListener {
  25  public:
  26   virtual void OnNativeFocusChanged(gfx::NativeView focused_now) = 0;
  27
  28  protected:
  29   virtual ~WidgetFocusChangeListener() {}
  30 };
  31
  32 class VIEWS_EXPORT WidgetFocusManager {
  33  public:
  34   // Returns the singleton instance.
  35   static WidgetFocusManager* GetInstance();
  36
  37   // Adds/removes a WidgetFocusChangeListener |listener| to the set of
  38   // active listeners.
  39   void AddFocusChangeListener(WidgetFocusChangeListener* listener);
  40   void RemoveFocusChangeListener(WidgetFocusChangeListener* listener);
  41
  42   // Called when native-focus shifts within, or off, a widget. |focused_now| is
  43   // null when focus is lost.
  44   void OnNativeFocusChanged(gfx::NativeView focused_now);
  45
  46   // Enable/Disable notification of registered listeners during calls
  47   // to OnNativeFocusChanged.  Used to prevent unwanted focus changes from
  48   // propagating notifications.
  49   void EnableNotifications() { enabled_ = true; }
  50   void DisableNotifications() { enabled_ = false; }
  51
  52  private:
  53   friend struct base::DefaultSingletonTraits<WidgetFocusManager>;
  54
  55   WidgetFocusManager();
  56   ~WidgetFocusManager();
  57
  58   base::ObserverList<WidgetFocusChangeListener> focus_change_listeners_;
  59
  60   bool enabled_;
  61
  62   DISALLOW_COPY_AND_ASSIGN(WidgetFocusManager);
  63 };
  64
  65 // A basic helper class that is used to disable native focus change
  66 // notifications within a scope.
  67 class VIEWS_EXPORT AutoNativeNotificationDisabler {
  68  public:
  69   AutoNativeNotificationDisabler();
  70   ~AutoNativeNotificationDisabler();
  71
  72  private:
  73   DISALLOW_COPY_AND_ASSIGN(AutoNativeNotificationDisabler);
  74 };
  75
  76 }  // namespace views
  77
  78 #endif  // UI_VIEWS_FOCUS_WIDGET_FOCUS_MANAGER_H_