I am able to set the background color of AppBar to Colors.amber. This automatically sets the text color to Black. I am aware of the accessibility i
title of AppBar uses headline6 and floatingActionBar uses color from primarySwatch. Though it is not documented in TextTheme, but I tested it. For example : to have red FloatingActionButton and blue title text in AppBar your theme inside MaterialApp should look like the following :
MaterialApp(
theme: ThemeData(
primarySwatch: Colors.red,
appBarTheme: AppBarTheme(
textTheme: TextTheme(
headline6: TextStyle(
color: Colors.blue,
fontWeight: FontWeight.bold,
fontSize: 28.0,
),
),
),
),
)