AnimatedTheme({Key key, @required ThemeData data, bool isMaterialAppTheme: false, Curve curve: Curves.linear, Duration duration: kThemeAnimationDuration, Widget child })

Creates an animated theme.

By default, the theme transition uses a linear curve. The data and child arguments must not be null.

Source 

AnimatedTheme({
  Key key,
  @required this.data,
  this.isMaterialAppTheme: false,
  Curve curve: Curves.linear,
  Duration duration: kThemeAnimationDuration,
  this.child
}) : super(key: key, curve: curve, duration: duration) {
  assert(child != null);
  assert(data != null);
}