Experimental app list: Added a current page indicator to the launcher.

ui/app_list/views/contents_switcher_view.cc

Index: ui/app_list/views/contents_switcher_view.cc
diff --git a/ui/app_list/views/contents_switcher_view.cc b/ui/app_list/views/contents_switcher_view.cc
index 95669439fdb2f06df7d6ed6533d0e8d832cb101b..fc8052fccdfe7ec961295bad70a900e3eb3a2059 100644
--- a/ui/app_list/views/contents_switcher_view.cc
+++ b/ui/app_list/views/contents_switcher_view.cc
@@ -6,17 +6,34 @@
 
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/views/contents_view.h"
+#include "ui/views/background.h"
 #include "ui/views/controls/button/custom_button.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/layout/box_layout.h"
+#include "ui/views/layout/fill_layout.h"
 
 namespace app_list {
 
 namespace {
 
-const int kPreferredHeight = 32;
+const int kPageIndicatorHeight = 1;
+const int kPreferredHeight = 32 + kPageIndicatorHeight;

[calamity, 2014/07/09 05:50:19]

Pull out 32 into kButtonImageSize.

[kcarattini, 2014/07/09 06:45:22]

Done.

 const int kButtonSpacing = 4;
 
+class ContentsPageIndicatorView : public views::View {
+ public:
+  ContentsPageIndicatorView() {};
+  virtual ~ContentsPageIndicatorView() {};
+
+  // Overridden from views::View:
+  virtual gfx::Size GetPreferredSize() const OVERRIDE {
+    return gfx::Size(0, kPageIndicatorHeight);
+  };
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ContentsPageIndicatorView);
+};
+
 }  // namespace
 
 ContentsSwitcherView::ContentsSwitcherView(ContentsView* contents_view)
@@ -37,7 +54,29 @@ void ContentsSwitcherView::AddSwitcherButton(int resource_id, int page_index) {
         ui::ResourceBundle::GetSharedInstance().GetImageSkiaNamed(resource_id));
   }
   button->set_tag(page_index);
-  buttons_->AddChildView(button);
+
+  // Add an indicator for the current launcher page.
+  app_list::ContentsPageIndicatorView* indicator =
+      new app_list::ContentsPageIndicatorView();
+  indicator->set_background(
+      views::Background::CreateSolidBackground(0, 0, 255));

[calamity, 2014/07/09 05:50:19]

Use app_list::kPagerSelectedColor.

[kcarattini, 2014/07/09 06:45:21]

Done.

+  indicator->SetFillsBoundsOpaquely(true);

[calamity, 2014/07/09 05:50:19]

I don't think this does anything. This is an option for aura layers.

[kcarattini, 2014/07/09 06:45:22]

Done.

+  indicator->SetVisible(false);
+
+  views::View* indicator_container = new views::View();

[calamity, 2014/07/09 05:50:19]

// A container view that will consume space when its child is not visible.
// TODO(calamity): Remove this once BoxLayout supports space-consuming invisible
views.

[kcarattini, 2014/07/09 06:45:21]

Done.

+  indicator_container->SetLayoutManager(new views::FillLayout());
+  indicator_container->AddChildView(indicator);
+
+  views::View* button_indicator_container = new views::View();

[calamity, 2014/07/09 05:50:19]

Maybe button_container? Either way, this should have a comment like:
// View containing the indicator view and image button.

[kcarattini, 2014/07/09 06:45:22]

Done.

+  views::BoxLayout* layout_manager =
+      new views::BoxLayout(views::BoxLayout::kVertical, 0, 0, 0);
+  layout_manager->set_main_axis_alignment(
+      views::BoxLayout::MAIN_AXIS_ALIGNMENT_CENTER);
+  button_indicator_container->SetLayoutManager(layout_manager);
+  button_indicator_container->AddChildView(indicator_container);
+  button_indicator_container->AddChildView(button);
+
+  buttons_->AddChildView(button_indicator_container);
 }
 
 gfx::Size ContentsSwitcherView::GetPreferredSize() const {
@@ -61,4 +100,16 @@ void ContentsSwitcherView::ButtonPressed(views::Button* sender,
   contents_view_->SetActivePage(sender->tag());
 }
 
+void ContentsSwitcherView::SelectedPageChanged(int old_selected,
+                                               int new_selected) {
+  if (old_selected >= 0 && old_selected < buttons_->child_count()) {
+    buttons_->child_at(old_selected)->child_at(0)->child_at(0)->SetVisible(
+        false);
+  }
+  if (new_selected >= 0 && new_selected < buttons_->child_count()) {
+    buttons_->child_at(new_selected)->child_at(0)->child_at(0)->SetVisible(
+        true);

[calamity, 2014/07/09 05:50:18]

It would be better to make a private member

// Owned by views hierarchy.
std::vector<view::View*> page_active_indicators_;

where you keep pointers to all the indicator views you create and then access
them here.

[kcarattini, 2014/07/09 06:45:21]

Done.

+  }
+}
+
 }  // namespace app_list