foregroundColor property
The default foreground color for icons and text within the button.
If this property is null, then the FloatingActionButtonThemeData.foregroundColor of ThemeData.floatingActionButtonTheme is used. If that property is also null, then the ColorScheme.onSecondary color of ThemeData.colorScheme is used.
Although the color of theme's accentIconTheme currently provides a
default that supersedes the onSecondary color, this dependency
has been deprecated: https://flutter.dev/go/remove-fab-accent-theme-dependency.
It will be removed in the future.
Implementation
final Color? foregroundColor;