view_observer.h revision 6e8cce623b6e4fe0c9e4af605d675dd9d0338c38 
1// Copyright 2014 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 MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_OBSERVER_H_
6#define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_OBSERVER_H_
7
8#include <vector>
9
10#include "base/basictypes.h"
11
12#include "mojo/services/public/cpp/view_manager/view.h"
13#include "mojo/services/public/interfaces/input_events/input_events.mojom.h"
14
15namespace gfx {
16class Rect;
17}
18
19namespace mojo {
20
21class View;
22
23// A note on -ing and -ed suffixes:
24//
25// -ing methods are called before changes are applied to the local view model.
26// -ed methods are called after changes are applied to the local view model.
27//
28// If the change originated from another connection to the view manager, it's
29// possible that the change has already been applied to the service-side model
30// prior to being called, so for example in the case of OnViewDestroying(), it's
31// possible the view has already been destroyed on the service side.
32
33class ViewObserver {
34 public:
35  struct TreeChangeParams {
36    TreeChangeParams();
37    View* target;
38    View* old_parent;
39    View* new_parent;
40    View* receiver;
41  };
42
43  virtual void OnTreeChanging(const TreeChangeParams& params) {}
44  virtual void OnTreeChanged(const TreeChangeParams& params) {}
45
46  virtual void OnViewReordering(View* view,
47                                View* relative_view,
48                                OrderDirection direction) {}
49  virtual void OnViewReordered(View* view,
50                               View* relative_view,
51                               OrderDirection direction) {}
52
53  virtual void OnViewDestroying(View* view) {}
54  virtual void OnViewDestroyed(View* view) {}
55
56  virtual void OnViewBoundsChanging(View* view,
57                                    const gfx::Rect& old_bounds,
58                                    const gfx::Rect& new_bounds) {}
59  virtual void OnViewBoundsChanged(View* view,
60                                   const gfx::Rect& old_bounds,
61                                   const gfx::Rect& new_bounds) {}
62
63  virtual void OnViewFocusChanged(View* gained_focus, View* lost_focus) {}
64
65  virtual void OnViewInputEvent(View* view, const EventPtr& event) {}
66
67 protected:
68  virtual ~ViewObserver() {}
69};
70
71}  // namespace mojo
72
73#endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_OBSERVER_H_
74