[Chrome OS] Change layout of the launcher.

ui/app_list/views/start_page_view.cc

 // Copyright 2014 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/start_page_view.h"
 
+#include <algorithm>
 #include <string>
 
 #include "base/i18n/rtl.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_item.h"
 #include "ui/app_list/app_list_model.h"
 #include "ui/app_list/app_list_view_delegate.h"
 #include "ui/app_list/search_result.h"
 #include "ui/app_list/views/all_apps_tile_item_view.h"
 #include "ui/app_list/views/app_list_main_view.h"
 #include "ui/app_list/views/contents_view.h"
 #include "ui/app_list/views/custom_launcher_page_view.h"
 #include "ui/app_list/views/search_box_view.h"
 #include "ui/app_list/views/search_result_container_view.h"
 #include "ui/app_list/views/search_result_tile_item_view.h"
 #include "ui/app_list/views/tile_item_view.h"
 #include "ui/gfx/canvas.h"
 #include "ui/views/background.h"
 #include "ui/views/controls/image_view.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/textfield/textfield.h"
 #include "ui/views/layout/box_layout.h"
+#include "ui/views/layout/grid_layout.h"
 #include "ui/views/widget/widget.h"
 
 namespace app_list {
 
 namespace {
 
 // Layout constants.
 const int kInstantContainerSpacing = 24;
 const int kSearchBoxAndTilesSpacing = 35;
 const int kStartPageSearchBoxWidth = 480;
 
 // WebView constants.
 const int kWebViewWidth = 700;
 const int kWebViewHeight = 244;
 
 // Tile container constants.
-const size_t kNumStartPageTiles = 4;
 const int kTileSpacing = 7;
+const int kNumStartPageTilesCols = 5;
+const int kTilesHorizontalMarginLeft = 145;

[xiyuan, 2016/08/09 17:49:09]

nit: const int -> constexpr int here and all other consts

[xdai1, 2016/08/09 20:14:17]

Done.

 
 const int kLauncherPageBackgroundWidth = 400;
 
 // An invisible placeholder view which fills the space for the search box view
 // in a box layout. The search box view itself is a child of the AppListView
 // (because it is visible on many different pages).
 class SearchBoxSpacerView : public views::View {
  public:
   explicit SearchBoxSpacerView(const gfx::Size& search_box_size)
       : size_(kStartPageSearchBoxWidth, search_box_size.height()) {}
@@ skipping 63 matching lines @@
 
   // Overridden from SearchResultContainerView:
   int Update() override;
   void UpdateSelectedIndex(int old_selected, int new_selected) override;
   void OnContainerSelected(bool from_bottom,
                            bool directional_movement) override;
   void NotifyFirstResultYIndex(int y_index) override;
   int GetYSize() override;
 
  private:
+  void CreateAppsGrid(int apps_num);
+
   ContentsView* contents_view_;
+  AppListViewDelegate* view_delegate_;
 
   std::vector<SearchResultTileItemView*> search_result_tile_views_;
   AllAppsTileItemView* all_apps_button_;
 
   DISALLOW_COPY_AND_ASSIGN(StartPageTilesContainer);
 };
 
 StartPageView::StartPageTilesContainer::StartPageTilesContainer(
     ContentsView* contents_view,
     AllAppsTileItemView* all_apps_button,
     AppListViewDelegate* view_delegate)
-    : contents_view_(contents_view), all_apps_button_(all_apps_button) {
-  views::BoxLayout* tiles_layout_manager =
-      new views::BoxLayout(views::BoxLayout::kHorizontal, 0, 0, kTileSpacing);
-  tiles_layout_manager->set_main_axis_alignment(
-      views::BoxLayout::MAIN_AXIS_ALIGNMENT_CENTER);
-  SetLayoutManager(tiles_layout_manager);
+    : contents_view_(contents_view),
+      view_delegate_(view_delegate),
+      all_apps_button_(all_apps_button) {
   set_background(
       views::Background::CreateSolidBackground(kLabelBackgroundColor));
-
-  // Add SearchResultTileItemViews to the container.
-  for (size_t i = 0; i < kNumStartPageTiles; ++i) {
-    SearchResultTileItemView* tile_item =
-        new SearchResultTileItemView(this, view_delegate);
-    AddChildView(tile_item);
-    tile_item->SetParentBackgroundColor(kLabelBackgroundColor);
-    tile_item->SetHoverStyle(TileItemView::HOVER_STYLE_ANIMATE_SHADOW);
-    search_result_tile_views_.push_back(tile_item);
-  }
-
-  // Also add a special "all apps" button to the end of the container.
   all_apps_button_->SetHoverStyle(TileItemView::HOVER_STYLE_ANIMATE_SHADOW);
-  all_apps_button_->UpdateIcon();
   all_apps_button_->SetParentBackgroundColor(kLabelBackgroundColor);
-  AddChildView(all_apps_button_);
+  CreateAppsGrid(kNumStartPageTiles);
 }
 
 StartPageView::StartPageTilesContainer::~StartPageTilesContainer() {
 }
 
 TileItemView* StartPageView::StartPageTilesContainer::GetTileItemView(
     int index) {
   DCHECK_GT(num_results(), index);
   if (index == num_results() - 1)
     return all_apps_button_;
 
   return search_result_tile_views_[index];
 }
 
 int StartPageView::StartPageTilesContainer::Update() {
   // Ignore updates and disable buttons when transitioning to a different
   // state.
   if (contents_view_->GetActiveState() != AppListModel::STATE_START) {
     for (auto* view : search_result_tile_views_)
       view->SetEnabled(false);
 
     return num_results();
   }
 
   std::vector<SearchResult*> display_results =
       AppListModel::FilterSearchResultsByDisplayType(
           results(), SearchResult::DISPLAY_RECOMMENDATION, kNumStartPageTiles);
+  if (display_results.size() != search_result_tile_views_.size()) {
+    // We should recreate the grid layout in this case.
+    for (size_t i = 0; i < search_result_tile_views_.size(); i++) {
+      RemoveChildView(search_result_tile_views_[i]);

[xiyuan, 2016/08/09 17:49:09]

Not necessary. Deleting a view would remove it from its parent [1].

[1] https://cs.chromium.org/chromium/src/ui/views/view.cc?rcl=0&l=127

[xdai1, 2016/08/09 20:14:18]

Done.

+      delete search_result_tile_views_[i];
+    }
+    search_result_tile_views_.clear();
+    RemoveChildView(all_apps_button_);
+    CreateAppsGrid(std::min(kNumStartPageTiles, display_results.size()));
+  }
 
   // Update the tile item results.
   for (size_t i = 0; i < search_result_tile_views_.size(); ++i) {
-    SearchResult* item = NULL;
+    SearchResult* item = nullptr;
     if (i < display_results.size())
       item = display_results[i];
     search_result_tile_views_[i]->SetSearchResult(item);
     search_result_tile_views_[i]->SetEnabled(true);
   }
 
   Layout();
   parent()->Layout();
   // Add 1 to the results size to account for the all apps button.
   return display_results.size() + 1;
@@ skipping 18 matching lines @@
 void StartPageView::StartPageTilesContainer::NotifyFirstResultYIndex(
     int /*y_index*/) {
   NOTREACHED();
 }
 
 int StartPageView::StartPageTilesContainer::GetYSize() {
   NOTREACHED();
   return 0;
 }
 
+void StartPageView::StartPageTilesContainer::CreateAppsGrid(int apps_num) {
+  DCHECK(search_result_tile_views_.empty());
+  views::GridLayout* tiles_layout_manager = new views::GridLayout(this);
+  SetLayoutManager(tiles_layout_manager);
+
+  views::ColumnSet* column_set = tiles_layout_manager->AddColumnSet(0);
+  column_set->AddPaddingColumn(0, kTilesHorizontalMarginLeft);
+  for (int col = 0; col < kNumStartPageTilesCols; col++) {

[xiyuan, 2016/08/09 17:49:09]

nit: col++ -> ++col

[xdai1, 2016/08/09 20:14:17]

I think they're same?

[xiyuan, 2016/08/09 20:22:12]

Haha... This used to be an interview question asked by Google. :)

It maybe true that modern compiler would optimize and makes the two forms to
have the same efficiency. But google prefers ++i when you can, see C++ style
guide:

https://google.github.io/styleguide/cppguide.html#Preincrement_and_Predecrement

[xdai1, 2016/08/09 20:33:06]

I see. Thanks!

+    column_set->AddColumn(views::GridLayout::FILL, views::GridLayout::FILL, 0,
+                          views::GridLayout::USE_PREF, 0, 0);
+    column_set->AddPaddingColumn(0, kTileSpacing);
+  }
+
+  // Add SearchResultTileItemViews to the container.
+  int i = 0;
+  for (; i < apps_num; i++) {

[xiyuan, 2016/08/09 17:49:09]

nit: i++ -> ++i

[xdai1, 2016/08/09 20:14:17]

same?

+    SearchResultTileItemView* tile_item =
+        new SearchResultTileItemView(this, view_delegate_);
+    if (i % kNumStartPageTilesCols == 0)
+      tiles_layout_manager->StartRow(0, 0);
+    tiles_layout_manager->AddView(tile_item);
+    AddChildView(tile_item);
+    tile_item->SetParentBackgroundColor(kLabelBackgroundColor);
+    tile_item->SetHoverStyle(TileItemView::HOVER_STYLE_ANIMATE_SHADOW);
+    search_result_tile_views_.push_back(tile_item);
+  }
+
+  // Also add a special "all apps" button to the end of the container.
+  all_apps_button_->UpdateIcon();
+  if (i % kNumStartPageTilesCols == 0)
+    tiles_layout_manager->StartRow(0, 0);
+  tiles_layout_manager->AddView(all_apps_button_);
+  AddChildView(all_apps_button_);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // StartPageView implementation:
 StartPageView::StartPageView(AppListMainView* app_list_main_view,
                              AppListViewDelegate* view_delegate)
     : app_list_main_view_(app_list_main_view),
       view_delegate_(view_delegate),
       search_box_spacer_view_(new SearchBoxSpacerView(
           app_list_main_view->search_box_view()->GetPreferredSize())),
       instant_container_(new views::View),
       custom_launcher_page_background_(new CustomLauncherPageBackgroundView(
@@ skipping 247 matching lines @@
   // is enabled).
   if (event->type() == ui::ET_SCROLL && event->y_offset() < 0)
     MaybeOpenCustomLauncherPage();
 }
 
 TileItemView* StartPageView::GetTileItemView(size_t index) {
   return tiles_container_->GetTileItemView(index);
 }
 
 }  // namespace app_list