TextButtonThemeData

style:

flatButtonStyle

),

elevatedButtonTheme:

ElevatedButtonThemeData

style:

raisedButtonStyle

),

outlinedButtonTheme:

OutlinedButtonThemeData

style:

outlineButtonStyle

),

),

To restore the default appearance for buttons in part of an
application you can wrap a widget subtree with TextButtonTheme,
ElevatedButtonTheme, or OutlinedButtonTheme. For example:

TextButtonTheme

data:

TextButtonThemeData

style:

flatButtonStyle

),

child:

myWidgetSubtree

Migrating buttons with custom colors