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 OnNativeFocusChange(gfx::NativeView focused_before,
  25                                    gfx::NativeView focused_now) = 0;
  26
  27  protected:
  28   virtual ~WidgetFocusChangeListener() {}
  29 };
  30
  31 class VIEWS_EXPORT WidgetFocusManager {
  32  public:
  33   // Returns the singleton instance.
  34   static WidgetFocusManager* GetInstance();
  35
  36   // Adds/removes a WidgetFocusChangeListener |listener| to the set of
  37   // active listeners.
  38   void AddFocusChangeListener(WidgetFocusChangeListener* listener);
  39   void RemoveFocusChangeListener(WidgetFocusChangeListener* listener);
  40
  41   // To be called when native-focus shifts from |focused_before| to
  42   // |focused_now|.
  43   // TODO(port) : Invocations to this routine are only implemented for
  44   // the Win32 platform.  Calls need to be placed appropriately for
  45   // non-Windows environments.
  46   void OnWidgetFocusEvent(gfx::NativeView focused_before,
  47                           gfx::NativeView focused_now);
  48
  49   // Enable/Disable notification of registered listeners during calls
  50   // to OnWidgetFocusEvent.  Used to prevent unwanted focus changes from
  51   // propagating notifications.
  52   void EnableNotifications() { enabled_ = true; }
  53   void DisableNotifications() { enabled_ = false; }
  54
  55  private:
  56   friend struct DefaultSingletonTraits<WidgetFocusManager>;
  57
  58   WidgetFocusManager();
  59   ~WidgetFocusManager();
  60
  61   ObserverList<WidgetFocusChangeListener> focus_change_listeners_;
  62
  63   bool enabled_;
  64
  65   DISALLOW_COPY_AND_ASSIGN(WidgetFocusManager);
  66 };
  67
  68 // A basic helper class that is used to disable native focus change
  69 // notifications within a scope.
  70 class VIEWS_EXPORT AutoNativeNotificationDisabler {
  71  public:
  72   AutoNativeNotificationDisabler();
  73   ~AutoNativeNotificationDisabler();
  74
  75  private:
  76   DISALLOW_COPY_AND_ASSIGN(AutoNativeNotificationDisabler);
  77 };
  78
  79 }  // namespace views
  80
  81 #endif  // UI_VIEWS_FOCUS_WIDGET_FOCUS_MANAGER_H_