AppBar constructor

AppBar({Key key, Widget leading, bool automaticallyImplyLeading: true, Widget title, List<Widget> actions, Widget flexibleSpace, PreferredSizeWidget bottom, double elevation: 4.0, Color backgroundColor, Brightness brightness, IconThemeData iconTheme, TextTheme textTheme, bool primary: true, bool centerTitle, double titleSpacing: NavigationToolbar.kMiddleSpacing, double toolbarOpacity: 1.0, double bottomOpacity: 1.0 })

Creates a material design app bar.

The arguments elevation, primary, toolbarOpacity, bottomOpacity and automaticallyImplyLeading must not be null.

Typically used in the Scaffold.appBar property.

Implementation 

AppBar({
  Key key,
  this.leading,
  this.automaticallyImplyLeading = true,
  this.title,
  this.actions,
  this.flexibleSpace,
  this.bottom,
  this.elevation = 4.0,
  this.backgroundColor,
  this.brightness,
  this.iconTheme,
  this.textTheme,
  this.primary = true,
  this.centerTitle,
  this.titleSpacing = NavigationToolbar.kMiddleSpacing,
  this.toolbarOpacity = 1.0,
  this.bottomOpacity = 1.0,
}) : assert(automaticallyImplyLeading != null),
     assert(elevation != null),
     assert(primary != null),
     assert(titleSpacing != null),
     assert(toolbarOpacity != null),
     assert(bottomOpacity != null),
     preferredSize = Size.fromHeight(kToolbarHeight + (bottom?.preferredSize?.height ?? 0.0)),
     super(key: key);