Refactor app list event handling and prerendering.

ui/app_list/views/apps_container_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/apps_container_view.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/command_line.h"
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_folder_item.h"
 #include "ui/app_list/app_list_switches.h"
+#include "ui/app_list/pagination_model.h"
 #include "ui/app_list/views/app_list_folder_view.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_grid_view.h"
 #include "ui/app_list/views/folder_background_view.h"
 #include "ui/events/event.h"
 
 namespace app_list {
 
+namespace {
+
+const int kMinMouseWheelToSwitchPage = 20;
+const int kMinScrollToSwitchPage = 20;
+const int kMinHorizVelocityToSwitchPage = 800;
+
+const double kFinishTransitionThreshold = 0.33;
+
+}  // namespace
+
 AppsContainerView::AppsContainerView(AppListMainView* app_list_main_view,
                                      AppListModel* model)
     : model_(model),
       show_state_(SHOW_NONE),
       top_icon_animation_pending_count_(0) {
   apps_grid_view_ = new AppsGridView(app_list_main_view);
   int cols = kPreferredCols;
   int rows = kPreferredRows;
   // ShouldCenterWindow also implies that it is wide instead of tall.
   if (app_list_main_view->ShouldCenterWindow()) {
@@ skipping 97 matching lines @@
   }
 }
 
 bool AppsContainerView::OnKeyPressed(const ui::KeyEvent& event) {
   if (show_state_ == SHOW_APPS)
     return apps_grid_view_->OnKeyPressed(event);
   else
     return app_list_folder_view_->OnKeyPressed(event);
 }
 
+bool AppsContainerView::OnMouseWheel(const ui::MouseWheelEvent& event) {
+  int offset;
+  if (abs(event.x_offset()) > abs(event.y_offset()))
+    offset = event.x_offset();
+  else
+    offset = event.y_offset();
+
+  if (abs(offset) > kMinMouseWheelToSwitchPage) {
+    if (!GetPaginationModel()->has_transition()) {
+      GetPaginationModel()->SelectPageRelative(offset > 0 ? -1 : 1, true);
+    }
+    return true;
+  }
+
+  return false;
+}
+
+void AppsContainerView::OnGestureEvent(ui::GestureEvent* event) {
+  switch (event->type()) {
+    case ui::ET_GESTURE_SCROLL_BEGIN:
+      GetPaginationModel()->StartScroll();
+      event->SetHandled();
+      return;
+    case ui::ET_GESTURE_SCROLL_UPDATE:
+      // event->details.scroll_x() > 0 means moving contents to right. That is,
+      // transitioning to previous page.
+      GetPaginationModel()->UpdateScroll(event->details().scroll_x() /
+                                         GetContentsBounds().width());
+      event->SetHandled();
+      return;
+    case ui::ET_GESTURE_SCROLL_END:
+      GetPaginationModel()->EndScroll(
+          GetPaginationModel()->transition().progress <
+          kFinishTransitionThreshold);
+      event->SetHandled();
+      return;
+    case ui::ET_SCROLL_FLING_START: {
+      GetPaginationModel()->EndScroll(true);
+      if (fabs(event->details().velocity_x()) > kMinHorizVelocityToSwitchPage) {
+        GetPaginationModel()->SelectPageRelative(
+            event->details().velocity_x() < 0 ? 1 : -1, true);
+      }
+      event->SetHandled();
+      return;
+    }
+    default:
+      break;
+  }
+}
+
+void AppsContainerView::OnScrollEvent(ui::ScrollEvent* event) {
+  if (event->type() == ui::ET_SCROLL_FLING_CANCEL)
+    return;
+
+  float offset;
+  if (std::abs(event->x_offset()) > std::abs(event->y_offset()))
+    offset = event->x_offset();
+  else
+    offset = event->y_offset();
+
+  if (std::abs(offset) > kMinScrollToSwitchPage) {
+    if (!GetPaginationModel()->has_transition()) {
+      GetPaginationModel()->SelectPageRelative(offset > 0 ? -1 : 1, true);
+    }
+    event->SetHandled();
+    event->StopPropagation();
+  }
+}
+
 void AppsContainerView::OnTopIconAnimationsComplete() {
   --top_icon_animation_pending_count_;
 
   if (!top_icon_animation_pending_count_) {
     // Clean up the transitional views used for top item icon animation.
     top_icon_views_.clear();
 
     // Show the folder icon when closing the folder.
     if ((show_state_ == SHOW_APPS || show_state_ == SHOW_ITEM_REPARENT) &&
         apps_grid_view_->activated_folder_item_view()) {
@@ skipping 43 matching lines @@
   // Get the active folder's icon bounds relative to AppsContainerView.
   AppListItemView* folder_item_view =
       apps_grid_view_->activated_folder_item_view();
   gfx::Rect to_grid_view = folder_item_view->ConvertRectToParent(
       folder_item_view->GetIconBounds());
   gfx::Rect to_container = apps_grid_view_->ConvertRectToParent(to_grid_view);
 
   return AppListFolderItem::GetTopIconsBounds(to_container);
 }
 
+PaginationModel* AppsContainerView::GetPaginationModel() {
+  return apps_grid_view_->pagination_model();
+}
+
 void AppsContainerView::CreateViewsForFolderTopItemsAnimation(
     AppListFolderItem* active_folder,
     bool open_folder) {
   top_icon_views_.clear();
   std::vector<gfx::Rect> top_items_bounds =
       GetTopItemIconBoundsInActiveFolder();
   top_icon_animation_pending_count_ =
       std::min(kNumFolderTopItems, active_folder->item_list()->item_count());
   for (size_t i = 0; i < top_icon_animation_pending_count_; ++i) {
     if (active_folder->GetTopIcon(i).isNull())
@@ skipping 17 matching lines @@
 void AppsContainerView::PrepareToShowApps(AppListFolderItem* folder_item) {
   if (folder_item)
     CreateViewsForFolderTopItemsAnimation(folder_item, false);
 
   // Hide the active folder item until the animation completes.
   if (apps_grid_view_->activated_folder_item_view())
     apps_grid_view_->activated_folder_item_view()->SetVisible(false);
 }
 
 }  // namespace app_list