const IconButton({Key key, double size: 24.0, EdgeInsets padding: const EdgeInsets.all(8.0), FractionalOffset alignment: FractionalOffset.center, @required Widget icon, Color color, Color disabledColor, @required VoidCallback onPressed, String tooltip })

Creates an icon button.

Icon buttons are commonly used in the actions field, but they can be used in many other places as well.

Requires one of its ancestors to be a Material widget.

The size, padding, and alignment arguments must not be null (though they each have default values).

The icon argument must be specified, and is typically either an Icon or an ImageIcon.

Source 

const IconButton({
  Key key,
  this.size: 24.0,
  this.padding: const EdgeInsets.all(8.0),
  this.alignment: FractionalOffset.center,
  @required this.icon,
  this.color,
  this.disabledColor,
  @required this.onPressed,
  this.tooltip
}) : super(key: key);