ui/aura/window_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_AURA_WINDOW_OBSERVER_H_
   6 #define UI_AURA_WINDOW_OBSERVER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/strings/string16.h"
  10 #include "ui/aura/aura_export.h"
  11
  12 namespace gfx {
  13 class Rect;
  14 }  // namespace gfx
  15
  16 namespace aura {
  17
  18 class Window;
  19
  20 class AURA_EXPORT WindowObserver {
  21  public:
  22   struct HierarchyChangeParams {
  23     enum HierarchyChangePhase {
  24       HIERARCHY_CHANGING,
  25       HIERARCHY_CHANGED
  26     };
  27
  28     Window* target;     // The window that was added or removed.
  29     Window* new_parent;
  30     Window* old_parent;
  31     HierarchyChangePhase phase;
  32     Window* receiver;   // The window receiving the notification.
  33   };
  34
  35   WindowObserver();
  36
  37   // Called when a window is added or removed. Notifications are sent to the
  38   // following hierarchies in this order:
  39   // 1. |target|.
  40   // 2. |target|'s child hierarchy.
  41   // 3. |target|'s parent hierarchy in its |old_parent|
  42   //        (only for Changing notifications).
  43   // 3. |target|'s parent hierarchy in its |new_parent|.
  44   //        (only for Changed notifications).
  45   // This sequence is performed via the Changing and Changed notifications below
  46   // before and after the change is committed.
  47   virtual void OnWindowHierarchyChanging(const HierarchyChangeParams& params) {}
  48   virtual void OnWindowHierarchyChanged(const HierarchyChangeParams& params) {}
  49
  50   // Invoked when |new_window| has been added as a child of this window.
  51   virtual void OnWindowAdded(Window* new_window) {}
  52
  53   // Invoked prior to removing |window| as a child of this window.
  54   virtual void OnWillRemoveWindow(Window* window) {}
  55
  56   // Invoked when this window's parent window changes.  |parent| may be NULL.
  57   virtual void OnWindowParentChanged(Window* window, Window* parent) {}
  58
  59   // Invoked when SetProperty(), ClearProperty(), or
  60   // NativeWidgetAura::SetNativeWindowProperty() is called on the window.
  61   // |key| is either a WindowProperty<T>* (SetProperty, ClearProperty)
  62   // or a const char* (SetNativeWindowProperty). Either way, it can simply be
  63   // compared for equality with the property constant. |old| is the old property
  64   // value, which must be cast to the appropriate type before use.
  65   virtual void OnWindowPropertyChanged(Window* window,
  66                                        const void* key,
  67                                        intptr_t old) {}
  68
  69   // Invoked when SetVisible() is invoked on a window. |visible| is the
  70   // value supplied to SetVisible(). If |visible| is true, window->IsVisible()
  71   // may still return false. See description in Window::IsVisible() for details.
  72   virtual void OnWindowVisibilityChanging(Window* window, bool visible) {}
  73   virtual void OnWindowVisibilityChanged(Window* window, bool visible) {}
  74
  75   // Invoked when SetBounds() is invoked on |window|. |old_bounds| and
  76   // |new_bounds| are in parent coordinates.
  77   virtual void OnWindowBoundsChanged(Window* window,
  78                                      const gfx::Rect& old_bounds,
  79                                      const gfx::Rect& new_bounds) {}
  80
  81   // Invoked when SetTransform() is invoked on |window|.
  82   virtual void OnWindowTransforming(Window* window) {}
  83   virtual void OnWindowTransformed(Window* window) {}
  84
  85   // Invoked when |window|'s position among its siblings in the stacking order
  86   // has changed.
  87   virtual void OnWindowStackingChanged(Window* window) {}
  88
  89   // Invoked when a region of |window| has damage from a new delegated frame.
  90   virtual void OnDelegatedFrameDamage(Window* window,
  91                                       const gfx::Rect& damage_rect_in_dip) {}
  92
  93   // Invoked when the Window is being destroyed (i.e. from the start of its
  94   // destructor). This is called before the window is removed from its parent.
  95   virtual void OnWindowDestroying(Window* window) {}
  96
  97   // Invoked when the Window has been destroyed (i.e. at the end of
  98   // its destructor). This is called after the window is removed from
  99   // its parent.  Window automatically removes its WindowObservers
 100   // before calling this method, so the following code is no op.
 101   //
 102   // void MyWindowObserver::OnWindowDestroyed(aura::Window* window) {
 103   //    window->RemoveObserver(this);
 104   // }
 105   virtual void OnWindowDestroyed(Window* window) {}
 106
 107   // Called when a Window has been added to a RootWindow.
 108   virtual void OnWindowAddedToRootWindow(Window* window) {}
 109
 110   // Called when a Window is about to be removed from a root Window.
 111   // |new_root| contains the new root Window if it is being added to one
 112   // atomically.
 113   virtual void OnWindowRemovingFromRootWindow(Window* window,
 114                                               Window* new_root) {}
 115
 116   // Called when the window title has changed.
 117   virtual void OnWindowTitleChanged(Window* window) {}
 118
 119  protected:
 120   virtual ~WindowObserver();
 121
 122  private:
 123   friend class Window;
 124
 125   // Called when this is added as an observer on |window|.
 126   void OnObservingWindow(Window* window);
 127
 128   // Called when this is removed from the observers on |window|.
 129   void OnUnobservingWindow(Window* window);
 130
 131   // Tracks the number of windows being observed to track down
 132   // http://crbug.com/365364.
 133   int observing_;
 134
 135   DISALLOW_COPY_AND_ASSIGN(WindowObserver);
 136 };
 137
 138 }  // namespace aura
 139
 140 #endif  // UI_AURA_WINDOW_OBSERVER_H_