Implement animation UI for opening/closing an app list folder.

ui/app_list/views/app_list_folder_view.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/app_list/views/app_list_folder_view.h"
 
 #include <algorithm>
 
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_folder_item.h"
 #include "ui/app_list/app_list_model.h"
 #include "ui/app_list/pagination_model.h"
+#include "ui/app_list/views/app_list_item_view.h"
 #include "ui/app_list/views/app_list_main_view.h"
 #include "ui/app_list/views/apps_container_view.h"
 #include "ui/app_list/views/apps_grid_view.h"
 #include "ui/app_list/views/contents_view.h"
 #include "ui/app_list/views/folder_header_view.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/events/event.h"
 #include "ui/views/view_model.h"
 #include "ui/views/view_model_utils.h"
 
 namespace app_list {
 
 namespace {
 
 // Indexes of interesting views in ViewModel of AppListFolderView.
 const int kIndexFolderHeader = 0;
 const int kIndexChildItems = 1;
 
 }  // namespace
 
 AppListFolderView::AppListFolderView(AppsContainerView* container_view,
                                      AppListModel* model,
                                      AppListMainView* app_list_main_view,
                                      content::WebContents* start_page_contents)
     : container_view_(container_view),
       folder_header_view_(new FolderHeaderView(this)),
       view_model_(new views::ViewModel),
       folder_item_(NULL),
-      pagination_model_(new PaginationModel) {
+      pagination_model_(new PaginationModel),
+      animate_to_show_(false) {
   AddChildView(folder_header_view_);
   view_model_->Add(folder_header_view_, kIndexFolderHeader);
 
   items_grid_view_ = new AppsGridView(
       app_list_main_view, pagination_model_.get(), NULL);
   items_grid_view_->set_is_root_level(false);
   items_grid_view_->SetLayout(kPreferredIconDimension,
                               kPreferredCols,
                               kPreferredRows);
   items_grid_view_->SetModel(model);
   AddChildView(items_grid_view_);
   view_model_->Add(items_grid_view_, kIndexChildItems);
+
+#if defined(USE_AURA)
+  SetPaintToLayer(true);
+  SetFillsBoundsOpaquely(false);
+#endif
 }
 
 AppListFolderView::~AppListFolderView() {
   // Make sure |items_grid_view_| is deleted before |pagination_model_|.
   RemoveAllChildViews(true);
 }
 
 void AppListFolderView::SetAppListFolderItem(AppListFolderItem* folder) {
   folder_item_ = folder;
   items_grid_view_->SetItemList(folder_item_->item_list());
   folder_header_view_->SetFolderItem(folder_item_);
 }
 
+void AppListFolderView::ScheduleAnimationToShow(bool show) {
+  // Stop any previous animation.
+  layer()->GetAnimator()->StopAnimating();
+
+  animate_to_show_ = show;
+
+  // Hide the top items temporarily if showing the view for opening the folder.
+  if (show)
+    items_grid_view_->ShowTopItemViews(false);
+
+  // Set initial state.
+  SetVisible(true);
+  layer()->SetOpacity(show ? 0.0f : 1.0f);
+
+  ui::ScopedLayerAnimationSettings animation(layer()->GetAnimator());
+  animation.SetTweenType(gfx::Tween::EASE_IN_2);
+  animation.AddObserver(this);
+  animation.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
+      show ? kFolderTransitionInDurationMs : kFolderTransitionOutDurationMs));
+
+  layer()->SetOpacity(show ? 1.0f : 0.0f);
+}
+
 gfx::Size AppListFolderView::GetPreferredSize() {
   const gfx::Size header_size = folder_header_view_->GetPreferredSize();
   const gfx::Size grid_size = items_grid_view_->GetPreferredSize();
   int width = std::max(header_size.width(), grid_size.width());
   int height = header_size.height() + grid_size.height();
   return gfx::Size(width, height);
 }
 
 void AppListFolderView::Layout() {
   CalculateIdealBounds();
   views::ViewModelUtils::SetViewBoundsToIdealBounds(*view_model_);
 }
 
 bool AppListFolderView::OnKeyPressed(const ui::KeyEvent& event) {
   return items_grid_view_->OnKeyPressed(event);
 }
 
+void AppListFolderView::OnImplicitAnimationsCompleted() {
+  // Show the top items when the opening folder animation is done.
+  if (animate_to_show_) {

[xiyuan, 2014/01/16 01:46:48]

Can we check layer()->opacity to find it out? If so, we can probably get rid of
|animate_to_show_|.

[jennyz, 2014/01/16 17:49:52]

Done.

+    items_grid_view_->ShowTopItemViews(true);
+  }
+
+  if (!animate_to_show_)
+    SetVisible(false);
+}
+
 void AppListFolderView::CalculateIdealBounds() {
   gfx::Rect rect(GetContentsBounds());
   if (rect.IsEmpty())
     return;
 
   gfx::Rect header_frame(rect);
   gfx::Size size = folder_header_view_->GetPreferredSize();
   header_frame.set_height(size.height());
   view_model_->set_ideal_bounds(kIndexFolderHeader, header_frame);
 
   gfx::Rect grid_frame(rect);
   grid_frame.set_y(header_frame.height());
   view_model_->set_ideal_bounds(kIndexChildItems, grid_frame);
 }
 
+gfx::Rect AppListFolderView::GetItemIconBoundsAt(int index) {
+  AppListItemView* item_view = items_grid_view_->GetItemViewAt(index);
+  // Icon bounds relative to AppListItemView.
+  const gfx::Rect icon_bounds = item_view->GetIconBounds();
+  gfx::Rect to_apps_grid_view = item_view->ConvertRectToParent(icon_bounds);
+  gfx::Rect to_folder =
+      items_grid_view_->ConvertRectToParent(to_apps_grid_view);
+
+  // Get the icon image's bound.
+  to_folder.ClampToCenteredSize(
+      gfx::Size(kPreferredIconDimension, kPreferredIconDimension));
+
+  return to_folder;
+}
+
 void AppListFolderView::NavigateBack(AppListFolderItem* item,
                                      const ui::Event& event_flags) {
-  container_view_->ShowApps();
+  container_view_->ShowApps(item);
 }
 
 }  // namespace app_list