Outline OutlineChapterHeading

OutlineChapterHeading

The heading of a chapter whose messages show in the outline: an open chapter, or a closed one the reader has unfolded. It is a label line over the chapter's title, with an optional menu button. With closed: true it shows a "Fold" line instead of the label.

import 'package:agent_kit/agent_kit.dart';

Demo

Ongoing chapter: "Chapter · since Oct 29 · ongoing" over the title "Release notes", with the menu button at the right. The gallery's third chapter has ongoing: true, so OutlineList builds this heading instead of a card. The gallery passes chapterActions, so the button is shown.

No shot covers closed: true (the "Chapter closed · Fold" line). OutlineFoldState uses it for a chapter the reader has just unfolded while its heading is still in view (fold.deferred). The chapter keeps this heading until the reader scrolls away from it, and then it folds into a card.

Parameters

Parameter	Type	Notes
chapter	OutlineChapter (required)	Read: id, title, when, ongoing.
color	Color (required)	Passed in by OutlineList. The build does not read it: no colour is drawn from it.
onMenu	VoidCallback?	Opens the host's menu. The "More" button is left out when it is null.
closed	bool	Default false. When true, the first line reads "Chapter closed · Fold" and is tappable.
onFold	VoidCallback?	Called by a tap on "Chapter closed · Fold". Used only when closed is true.

Behaviour

• Label line: "Chapter · · ongoing" for an ongoing chapter, or "Chapter · · closed" for a closed one. With closed: true the line is "Chapter closed · Fold" instead.
• Title: one line, ellipsised, in the display face at typeScale.h2.
• The menu button (outline-chapter-menu-<id>) appears only when onMenu is not null.

OutlineList picks this widget for an ongoing chapter (ongoing is true), and for a chapter in fold.deferred (with closed: true and onFold set to fold.foldNow).

Theme roles

colors.textTertiary (label line and the Fold line), colors.textPrimary (title), typeScale.uiSmall (label line), typeScale.h2 (title, through tsDisplay), colors.iconTertiary (the menu button, through OutlineMoreButton).

Size classes

Does not read the size class. The title ellipsises on one line at any width.

Accessibility

• The menu button is OutlineMoreButton: Semantics(button: true, label: 'More') with an AppTooltip labelled "More".
• The Fold line is a Hover with onTap (key outline-chapter-fold-<id>). It has no separate semantic label.
• No reduced-motion handling in this file.

Gallery and tests

• Gallery scene: Outline (GalleryScene.outline, OutlineScene). The heading is the "Release notes" chapter, the scene's ongoing one.
• Golden: apps/gallery/test/component_shots_test.dart writes outline_chapter_heading (index 0), _light.png and _dark.png. The scene is in g_outline_1600_<theme>.png and g_outline_390_<theme>.png.
• Other tests, packages/agent_kit/test/outline/outline_test.dart: "chapter and section menus list the host actions"; "without host actions there is no menu button".

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