Описание тега flutter-appbar
A material design app bar.
The AppBar displays the toolbar widgets, leading, title, and actions, above the bottom (if any). The bottom is usually used for a TabBar.
An app bar consists of a toolbar and potentially other widgets, such as a TabBar and a FlexibleSpaceBar. App bars typically expose one or more common actions with IconButtons which are optionally followed by a PopupMenuButton for less common operations (sometimes called the "overflow menu").
App bars are typically used in the Scaffold.appBar property, which places the app bar as a fixed-height widget at the top of the screen. For a scrollable app bar, see SliverAppBar, which embeds an AppBar in a sliver for use in a CustomScrollView.