AnimatedPositionedDirectional constructor Null safety

const AnimatedPositionedDirectional(
  1. {Key? key,
  2. required Widget child,
  3. double? start,
  4. double? top,
  5. double? end,
  6. double? bottom,
  7. double? width,
  8. double? height,
  9. Curve curve = Curves.linear,
  10. required Duration duration,
  11. VoidCallback? onEnd}
)

Creates a widget that animates its position implicitly.

Only two out of the three horizontal values (start, end, width), and only two out of the three vertical values (top, bottom, height), can be set. In each case, at least one of the three must be null.

The curve and duration arguments must not be null.

Implementation

const AnimatedPositionedDirectional({
  super.key,
  required this.child,
  this.start,
  this.top,
  this.end,
  this.bottom,
  this.width,
  this.height,
  super.curve,
  required super.duration,
  super.onEnd,
}) : assert(start == null || end == null || width == null),
     assert(top == null || bottom == null || height == null);