extendBody property
Whether the body extends behind the app bar and bottom bar.
Defaults to true, matching iOS 26's design where content scrolls
behind the transparent navigation bar. When false, the body occupies
only the area between the bars (no overlap, no edge fading).
Set to false when the body widget manages its own internal layout
and does not know to add a manual top spacer for the app bar — for
example, a third-party chat widget, a full-screen form, or any widget
that renders to the full height of the space it is given. With
extendBody: false the scaffold positions the body precisely between
the bottom of the app bar and the top of the bottom bar, so the widget
fills exactly the visible content area without being obscured.
Implementation
final bool extendBody;