1 // Copyright (c) 2013 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_V2_PUBLIC_VIEW_OBSERVER_H_ 6 #define UI_V2_PUBLIC_VIEW_OBSERVER_H_ 7 8 #include "ui/v2/public/v2_export.h" 9 10 namespace gfx { 11 class Rect; 12 } 13 14 namespace v2 { 15 16 class View; 17 18 // Observe View disposition changes. -ing methods are called before the change 19 // is committed, -ed methods are called after. 20 class V2_EXPORT ViewObserver { 21 public: 22 // Whether a notification is being sent before or after some property has 23 // changed. 24 enum DispositionChangePhase { 25 DISPOSITION_CHANGING, 26 DISPOSITION_CHANGED 27 }; 28 29 // Tree. 30 struct TreeChangeParams { 31 TreeChangeParams(); 32 View* target; 33 View* old_parent; 34 View* new_parent; 35 View* receiver; 36 DispositionChangePhase phase; 37 }; 38 39 // Called when a node is added or removed. Notifications are sent to the 40 // following hierarchies in this order: 41 // 1. |target|. 42 // 2. |target|'s child hierarchy. 43 // 3. |target|'s parent hierarchy in its |old_parent| 44 // (only for Changing notifications). 45 // 3. |target|'s parent hierarchy in its |new_parent|. 46 // (only for Changed notifications). 47 // This sequence is performed via the OnTreeChange notification below before 48 // and after the change is committed. OnViewTreeChange(const TreeChangeParams & params)49 virtual void OnViewTreeChange(const TreeChangeParams& params) {} 50 51 // Disposition. OnViewDestroy(View * view,DispositionChangePhase phase)52 virtual void OnViewDestroy(View* view, DispositionChangePhase phase) {} OnViewBoundsChanged(View * view,const gfx::Rect & old_bounds,const gfx::Rect & new_bounds)53 virtual void OnViewBoundsChanged(View* view, 54 const gfx::Rect& old_bounds, 55 const gfx::Rect& new_bounds) {} OnViewVisibilityChange(View * view,DispositionChangePhase phase)56 virtual void OnViewVisibilityChange(View* view, 57 DispositionChangePhase phase) {} 58 59 protected: ~ViewObserver()60 virtual ~ViewObserver() {} 61 }; 62 63 } // namespace v2 64 65 #endif // UI_V2_PUBLIC_VIEW_OBSERVER_H_ 66