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