components/mus/public/cpp/view_observer.h

   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 COMPONENTS_MUS_PUBLIC_CPP_VIEW_OBSERVER_H_
   6 #define COMPONENTS_MUS_PUBLIC_CPP_VIEW_OBSERVER_H_
   7
   8 #include <vector>
   9
  10 #include "components/mus/public/cpp/view.h"
  11 #include "ui/mojo/events/input_events.mojom.h"
  12
  13 namespace mojo {
  14
  15 class View;
  16
  17 // A note on -ing and -ed suffixes:
  18 //
  19 // -ing methods are called before changes are applied to the local view model.
  20 // -ed methods are called after changes are applied to the local view model.
  21 //
  22 // If the change originated from another connection to the view manager, it's
  23 // possible that the change has already been applied to the service-side model
  24 // prior to being called, so for example in the case of OnViewDestroying(), it's
  25 // possible the view has already been destroyed on the service side.
  26
  27 class ViewObserver {
  28  public:
  29   struct TreeChangeParams {
  30     TreeChangeParams();
  31     View* target;
  32     View* old_parent;
  33     View* new_parent;
  34     View* receiver;
  35   };
  36
  37   virtual void OnTreeChanging(const TreeChangeParams& params) {}
  38   virtual void OnTreeChanged(const TreeChangeParams& params) {}
  39
  40   virtual void OnViewReordering(View* view,
  41                                 View* relative_view,
  42                                 OrderDirection direction) {}
  43   virtual void OnViewReordered(View* view,
  44                                View* relative_view,
  45                                OrderDirection direction) {}
  46
  47   virtual void OnViewDestroying(View* view) {}
  48   virtual void OnViewDestroyed(View* view) {}
  49
  50   virtual void OnViewBoundsChanging(View* view,
  51                                     const Rect& old_bounds,
  52                                     const Rect& new_bounds) {}
  53   virtual void OnViewBoundsChanged(View* view,
  54                                    const Rect& old_bounds,
  55                                    const Rect& new_bounds) {}
  56
  57   virtual void OnViewViewportMetricsChanged(
  58       View* view,
  59       const ViewportMetrics& old_metrics,
  60       const ViewportMetrics& new_metrics) {}
  61
  62   virtual void OnViewFocusChanged(View* gained_focus, View* lost_focus) {}
  63
  64   virtual void OnViewInputEvent(View* view, const EventPtr& event) {}
  65
  66   virtual void OnViewVisibilityChanging(View* view) {}
  67   virtual void OnViewVisibilityChanged(View* view) {}
  68
  69   // Invoked when this View's shared properties have changed. This can either
  70   // be caused by SetSharedProperty() being called locally, or by us receiving
  71   // a mojo message that this property has changed. If this property has been
  72   // added, |old_data| is null. If this property was removed, |new_data| is
  73   // null.
  74   virtual void OnViewSharedPropertyChanged(
  75       View* view,
  76       const std::string& name,
  77       const std::vector<uint8_t>* old_data,
  78       const std::vector<uint8_t>* new_data) {}
  79
  80   // Invoked when SetProperty() or ClearProperty() is called on the window.
  81   // |key| is either a WindowProperty<T>* (SetProperty, ClearProperty). Either
  82   // way, it can simply be compared for equality with the property
  83   // constant. |old| is the old property value, which must be cast to the
  84   // appropriate type before use.
  85   virtual void OnViewLocalPropertyChanged(View* view,
  86                                           const void* key,
  87                                           intptr_t old) {}
  88
  89   virtual void OnViewEmbeddedAppDisconnected(View* view) {}
  90
  91   // Sent when the drawn state changes. This is only sent for the root nodes
  92   // when embedded.
  93   virtual void OnViewDrawnChanging(View* view) {}
  94   virtual void OnViewDrawnChanged(View* view) {}
  95
  96  protected:
  97   virtual ~ViewObserver() {}
  98 };
  99
 100 }  // namespace mojo
 101
 102 #endif  // COMPONENTS_MUS_PUBLIC_CPP_VIEW_OBSERVER_H_