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chromium / chromium / src / e37c4b8426f19a34f7c221f7d058b41fd0e1eeb0 / . / ash / app_list
tree: e7280acbbeae5f21833558c52b9f9dbc100fa0f4 [path history] [tgz]
  1. model/
  2. resources/
  3. test/
  4. views/
  5. app_list_badge_controller.cc
  6. app_list_badge_controller.h
  7. app_list_bubble_event_filter.cc
  8. app_list_bubble_event_filter.h
  9. app_list_bubble_event_filter_unittest.cc
  10. app_list_bubble_presenter.cc
  11. app_list_bubble_presenter.h
  12. app_list_bubble_presenter_unittest.cc
  13. app_list_color_provider_impl.cc
  14. app_list_color_provider_impl.h
  15. app_list_controller_impl.cc
  16. app_list_controller_impl.h
  17. app_list_controller_impl_unittest.cc
  18. app_list_event_targeter.cc
  19. app_list_event_targeter.h
  20. app_list_feature_usage_metrics.cc
  21. app_list_feature_usage_metrics.h
  22. app_list_feature_usage_metrics_unittest.cc
  23. app_list_metrics.cc
  24. app_list_metrics.h
  25. app_list_metrics_unittest.cc
  26. app_list_model_provider.cc
  27. app_list_model_provider.h
  28. app_list_presenter_event_filter.cc
  29. app_list_presenter_event_filter.h
  30. app_list_presenter_impl.cc
  31. app_list_presenter_impl.h
  32. app_list_presenter_impl_unittest.cc
  33. app_list_presenter_unittest.cc
  34. app_list_test_api.cc
  35. app_list_test_view_delegate.cc
  36. app_list_test_view_delegate.h
  37. app_list_unittest.cc
  38. app_list_util.cc
  39. app_list_util.h
  40. app_list_view_delegate.h
  41. apps_grid_row_change_animator.cc
  42. apps_grid_row_change_animator.h
  43. BUILD.gn
  44. DEPS
  45. DIR_METADATA
  46. folder_image_unittest.cc
  47. grid_index.cc
  48. grid_index.h
  49. home_launcher_animation_info.h
  50. OWNERS
  51. paged_view_structure.cc
  52. paged_view_structure.h
  53. PRESUBMIT.py
  54. README.md
  55. test_app_list_client.cc
  56. test_app_list_client.h
ash/app_list/README.md

App List

“Launcher” is the user-visible name for this feature.

Feature summary

  • Apps exist on a list of pages. Each page can be partially full. Empty space appears at the end of each page. The app list does not support Android-style “holes” in the middle of a page.
  • Each page is a fixed-size grid (commonly 5x4).
  • Apps can be reordered by dragging. If an app is dragged below the last page, a new page is created. If a page's last app is removed, the page disappears.
  • Folders can be created by dragging an app on top of another app. Folders are one level deep (no folders inside folders). A folder that contains a large number of items shows pages which scroll horizontally.
  • Folders generally contain 2 or more items. When the second-to-last item from a folder is removed, the folder is deleted and the remaining items appears on the main app grid. Some special folders are allowed to contain 1 item (e.g. “Linux Apps”).
  • The app list is navigable with arrow keys. Apps can be reordered with Ctrl+arrow key. Folders can be created with Ctrl+Shift+arrow key. In addition to accessibility, keyboard shortcuts are helpful for quickly creating folders with large numbers of items.
  • The list of apps and their order is synced between devices. However, some built-in OEM apps do not appear on all devices (e.g. an HP-only app might not show up on an Acer Chromebook).
  • Default-installed apps may be deleted.

Code structure

//ash/app_list contains the view structure and data model. Before 2018 this code lived in //ui/app_list because the app list used to be supported on non-Chrome OS platforms.

//chrome/browser/ui/app_list contains app list code that has Profile dependencies. This includes sync support and communication with the App Service (which provides the list of installed apps).

Data model

Apps

The list of installed apps is provided by the App Service. It includes a variety of app types:

  • Built-in apps
  • Progressive web apps (PWAs)
  • Android apps (via ARC++)
  • Linux apps (via Crostini)
  • Deprecated platform apps (“Chrome Apps”, turning down in 2022)
  • Extension-based apps (a.k.a. bookmark apps)
  • “Remote” apps (used in enterprise environments, see bug for details)

Some of a user's apps might not be supported on their current device. For example, a user might have a device that does not support Crostini. Likewise, they might have a device on a new OS version (e.g. dev channel) that includes a new built-in app but also have devices on older OS versions that do not support that app.

Unsupported apps are not shown in the app list.

Sync data

See the AppListSpecifics protocol buffer

  • A sync item can be an app, a “remove default app” request, a folder, or a page break.
  • Items have an extension-style string id (e.g. Chrome Web Store is “ahfgeienlihckogmohjhadlkjgocpleb”)
  • The sync data does not contain an ordered list of items. Instead, each individual item has a string “ordinal” that the client uses to sort the views.
  • Pagination is handled via page break items.
  • Items that appear in folders store the id of the containing folder.
  • OEM apps always appear in the OEM folder, even though they might have a different parent (or no parent) in the sync data. One reason is because the same app might be considered an OEM app on device A, but not an OEM app on device B.
  • Items have a “pin ordinal”, used to pin and sort pinned apps on the shelf.

Note that the sync data does not contain which page an app is on, nor the app's position within a page.

Ordinals

For the app list, an ordinal is a string type that allows ordering and insertion without rewriting existing items. For example, with ordinals “aa” and “bb” you can create an ordinal “am” that sorts to the middle, without changing “aa” or “bb”.

App list model

ash::AppListModel is the core data model. There is a single copy of this model, owned by ash.

AppListModel owns an AppListItemList for the top-level grid of apps. AppListItemList contains items in the order they appear in the app list, across across all pages.

Each AppListItem contains AppListItemMetadata. The data is similar to the data provided by sync, but is more focused on display. As of March 2021 the data includes:

  • id (extension-style string, matching the sync item id)
  • name
  • app_status (e.g. ready/blocked/paused)
  • folder_id (a UUID, e.g. 5e47865b-c00b-4fd9-ac90-e174e1d28aad)
  • position (a string ordinal)
  • icon
  • type information (folder, persistent folder, page break)

The ash data model is not directly exposed to code in //chrome. Chrome has its own data about each item, with ChromeAppListModelUpdater owning a map of ChromeAppListItem. These items use the same metadata as AppListItem. This separation is left over from the mustash project, where code in //ash and //chrome used to run in separate processes, and hence could not directly share a model. See go/move-applist.

Folders

AppListFolderItem is a subclass of AppListItem. Each folder has its own AppListItemList. Items inside of folders do not appear in the top-level item list.

Folders do not contain page breaks. Each page must be filled before the next page is created.

While items inside a folder can be reordered, the order data is not persisted to sync.

Views

An AppListItemView represents each app. It is a button and has an image icon and a name label.

AppsGridView displays a grid of AppListItemViews. An AppsGridView is used to show the main app grid. A separate AppsGridView is used to show the contents of a folder.

AppsGridView has an AppListItemView for each app in the main list, even those that are not on the current page (and hence are not visible). AppsGridView also contains a PaginationModel, which has a list of views for each visual page.

When a folder is open, its AppListFolderView is stacked on top of the main apps grid view. Only one folder can be open at a time. The folder view contains its own AppsGridView.

Therefore the view hierarchy is approximately this:

  • AppsContainerView
    • (Suggestion related views)
    • AppsGridView
      • AppListItemView
      • AppListItemView
      • ...
    • (Page switcher related views)
    • AppListFolderView
      • AppsGridView
        • AppListItemView
        • AppListItemView
        • ...

You can run chrome with --ash-debug-shortcuts, open the launcher, and press Ctrl-Alt-Shift-V to see the full view hierarchy.

Testing

App list tests live in ash_unittests. Run the unit tests with:

testing/xvfb.py out/Default/ash_unittests

Tests for high level user actions (reordering icons, creating folders, etc.) are generally part of apps_grid_view_unittest.cc or app_list_presenter_delegate_unittest.cc.

Historical notes

The old demo binary in //ash/app_list/demo was removed in 2021.

The shelf was originally called the launcher (circa 2012).