Chrome SessionRail

SessionRail

The session list: the workspace header, the chats grouped under labelled headings, and a footer. This sheet also covers SessionRow (one chat in the list) and SessionGroup (the labelled run of chats in rail_model.dart).

import 'package:agent_kit/agent_kit.dart';

Demo

Column: the rail at 240 px wide, with grouped rows, a selected row, status marks and the footer.

Compact, 390 px: the same rail as a sliding screen. It is opened by the header's Sessions button and closes when a session is picked.

Parameters

Parameter	Type	Notes
workspaceName	String	Required. The name in the header, and in the Switch project label.
groups	List<SessionGroup>	Required. The chats, in groups.
selectedId	String?	The selected chat's id. The row is drawn selected.
detailFor	String? Function(ChatSummary chat)?	Returns the detail line for a chat's row.
now	DateTime?	The clock for row ages.
initials	String	Default ''. Initials for the avatar.
onSelect	ValueChanged<ChatSummary>?	Called when a row is tapped. The compact screen closes after it.
onNewChat	VoidCallback?	The New session button.
onSearch	VoidCallback?	The Search button.
onSwitchWorkspace	VoidCallback?	The workspace button.
onSettings	VoidCallback?	The Settings button.
onHide	VoidCallback?	The Hide sidebar button.
hasMore	bool	Default false. Shows the load-more row at the end of the list.
loadingMore	bool	Default false. The load-more row shows its loading label and ignores presses.
loadMoreFailed	bool	Default false. The load-more row shows its failure label and offers another try.
onLoadMore	VoidCallback?	Called by the load-more row.

SessionGroup

Parameter	Type	Notes
label	String	A heading such as "Today" or "Earlier".
chats	List<ChatSummary>	The chats in the group.

SessionRow

Parameter	Type	Notes
chat	ChatSummary	Required. The chat: its title and status.
detail	String?	The meta line.
selected	bool	Default false. Draws the selected background and the edge bar.
onTap	VoidCallback?	Tap callback.

Theme roles

BbTheme roles read in session_rail.dart:

• rail, railHover, railSelected, railInk, railMuted, railLine
• accent (the avatar background when no moss space colour is found)
• colors.bgPrimary, colors.textPrimary (the avatar text)
• dangerInk (the failed load-more label)
• radii.ctl, typeScale.ui, brightness, formFactor
• The row's status mark uses status (BbStatusStyle per ChatStatus) through StatusMark.

Size classes

• Compact (scope.sizeClass.isCompact, below 600 px): the rail is the sliding screen opened from the header's Sessions button. select() sets scope.controller.open = false, so the screen closes after a pick (session_rail.dart:96).
• Medium and expanded: the rail is the 240 px column (Layout.sidebarWidth, see RailLayout).
• The Search button's shortcut hint is shown when formFactor != FormFactor.mobile (session_rail.dart:431), and the Search button's hint is Ctrl K through commandKeyHint.

Accessibility

• Button labels (tooltips and semantics): New session (rail-new-chat), Hide sidebar with shortcut Ctrl+B (rail-hide), Switch project, <name> (rail-workspace), Search with hint Ctrl K (rail-search), Settings (rail-settings).
• Load-more row (rail-load-more): Loading older sessions… while loading, Could not load older sessions. Try again after a failure, Show older sessions otherwise. Presses are ignored while loading.
• A selected row has a 3 px railInk edge bar and a title in weight 700 (unselected 500) (SessionRow).
• Row keys: rail-row-<chat id>.

Gallery and tests

• Gallery scene: the Components scene (apps/gallery/lib/src/components_scene.dart). Specimens: ChromeSpecimens in apps/gallery/lib/components/chrome.dart (the 240 px column is the first frame; the 390 px sliding screen is _SlidingRail).
• Golden shots: apps/gallery/test/component_shots_test.dart writes session_rail_column (SessionRail 0) and session_rail_compact (SessionRail 1) to apps/gallery/test/goldens/shots/. scenes_golden_test.dart covers the sheet as components_1000_light.png and components_1000_dark.png.
• packages/agent_kit/test/chrome/chrome_test.dart, group SessionRail: groups, rows with status meta and the footer; the load-more row; "says it is loading and ignores presses meanwhile"; "after a failure the row offers another try"; and the compact sliding screen.
• packages/agent_kit/test/chrome/chrome_golden_test.dart: chrome_rail_<brightness>.png, chrome_rail_more_<brightness>.png and chrome_rail_compact_390_<brightness>.png in packages/agent_kit/test/goldens/.
• packages/agent_kit/test/chrome/chrome_test.dart (group command key hints) covers the hint text.

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Generated from docs/components/chrome/SessionRail.md. Edit the file there; changes made on the wiki are overwritten.