Show separator in SearchResultTileItemListView

ui/app_list/views/search_result_tile_item_list_view.cc

Index: ui/app_list/views/search_result_tile_item_list_view.cc
diff --git a/ui/app_list/views/search_result_tile_item_list_view.cc b/ui/app_list/views/search_result_tile_item_list_view.cc
index 446d70041c6298ad5d511d61838ac3ecd9143691..71b6d83912cb146ebea1ff9b38093eacb8e55235 100644
--- a/ui/app_list/views/search_result_tile_item_list_view.cc
+++ b/ui/app_list/views/search_result_tile_item_list_view.cc
@@ -11,6 +11,7 @@
 #include "ui/app_list/app_list_features.h"
 #include "ui/app_list/app_list_view_delegate.h"
 #include "ui/app_list/search_result.h"
+#include "ui/app_list/views/search_result_separator.h"
 #include "ui/app_list/views/search_result_tile_item_view.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/views/background.h"
@@ -27,6 +28,7 @@ constexpr int kBetweenTileSpacing = 2;
 constexpr int kTopBottomPadding = 8;
 
 // Layout constants used when fullscreen app list feature is enabled.
+constexpr size_t kMaxNumSearchResultTiles = 6;
 constexpr int kItemListVerticalSpacing = 16;
 constexpr int kItemListHorizontalSpacing = 12;
 constexpr int kBetweenItemSpacing = 8;
@@ -39,7 +41,8 @@ SearchResultTileItemListView::SearchResultTileItemListView(
     views::Textfield* search_box,
     AppListViewDelegate* view_delegate)
     : search_box_(search_box),
-      is_fullscreen_app_list_enabled_(features::IsFullscreenAppListEnabled()) {
+      is_fullscreen_app_list_enabled_(features::IsFullscreenAppListEnabled()),
+      view_delegate_(view_delegate) {
   if (is_fullscreen_app_list_enabled_) {
     SetLayoutManager(new views::BoxLayout(
         views::BoxLayout::kHorizontal,
@@ -51,16 +54,16 @@ SearchResultTileItemListView::SearchResultTileItemListView(
         kBetweenTileSpacing));
   }
 
-  for (size_t i = 0; i < kNumSearchResultTiles; ++i) {
-    SearchResultTileItemView* tile_item =
-        new SearchResultTileItemView(this, view_delegate);
-    tile_item->SetParentBackgroundColor(kCardBackgroundColor);
-    if (!is_fullscreen_app_list_enabled_) {
+  if (!is_fullscreen_app_list_enabled_) {
+    for (size_t i = 0; i < kNumSearchResultTiles; ++i) {
+      SearchResultTileItemView* tile_item =
+          new SearchResultTileItemView(this, view_delegate);
+      tile_item->SetParentBackgroundColor(kCardBackgroundColor);
       tile_item->SetBorder(
           views::CreateEmptyBorder(kTopBottomPadding, 0, kTopBottomPadding, 0));
+      tile_views_.push_back(tile_item);
+      AddChildView(tile_item);
     }
-    tile_views_.push_back(tile_item);
-    AddChildView(tile_item);
   }
 }
 
@@ -92,11 +95,47 @@ int SearchResultTileItemListView::GetYSize() {
 int SearchResultTileItemListView::DoUpdate() {
   std::vector<SearchResult*> display_results =
       AppListModel::FilterSearchResultsByDisplayType(
-          results(), SearchResult::DISPLAY_TILE, kNumSearchResultTiles);
-  for (size_t i = 0; i < kNumSearchResultTiles; ++i) {
-    SearchResult* item =
-        i < display_results.size() ? display_results[i] : nullptr;
-    tile_views_[i]->SetSearchResult(item);
+          results(), SearchResult::DISPLAY_TILE,
+          is_fullscreen_app_list_enabled_ ? kMaxNumSearchResultTiles
+                                          : kNumSearchResultTiles);
+
+  if (is_fullscreen_app_list_enabled_) {
+    tile_views_.clear();
+    RemoveAllChildViews(true);

[xiyuan, 2017/06/23 15:43:09]

Removing then adding views is heavy and could result in UI flickering. That is
why current code pre-creates the tile views and update them in-place.

How about keeping this, adding separators between all tiles initially and
updating separators visibility here (and Layout())? 

[weidongg, 2017/06/23 18:32:20]

That's a better idea. Thanks. Done.

+    SearchResult::ResultType previous_type = SearchResult::RESULT_UNKNOWN;
+
+    for (size_t i = 0; i < display_results.size() &&
+                       tile_views_.size() < kMaxNumSearchResultTiles;
+         ++i) {
+      SearchResult* item = display_results[i];
+
+      if (item->result_type() != SearchResult::RESULT_UNKNOWN) {
+        SearchResultTileItemView* tile_item =
+            new SearchResultTileItemView(this, view_delegate_);
+        tile_item->SetParentBackgroundColor(kCardBackgroundColor);
+        tile_item->SetSearchResult(item);
+
+        if (item->result_type() != previous_type &&
+            previous_type != SearchResult::RESULT_UNKNOWN) {
+          // Add a separator to separate search results of different types.
+          // The strategy here is to only add a separator only if current search
+          // result type is different from the previous one. The strategy is
+          // based on the assumption that the search results are already
+          // separated in groups based on their result types.
+          AddChildView(new SearchResultSeparator);
+        }
+
+        tile_views_.push_back(tile_item);
+        AddChildView(tile_item);
+        previous_type = item->result_type();
+      }
+    }
+  } else {
+    for (size_t i = 0; i < kNumSearchResultTiles; ++i) {
+      SearchResult* item =
+          i < display_results.size() ? display_results[i] : nullptr;
+      tile_views_[i]->SetSearchResult(item);
+    }
   }
 
   set_container_score(