InkWell
A rectangular area of a Material that responds to touch.
Example
double sideLength = 50; Widget build(BuildContext context) { return Center( child: AnimatedContainer( height: sideLength, width: sideLength, duration: Duration(seconds: 2), curve: Curves.easeIn, child: Material( color: Colors.yellow, child: InkWell( onTap: () { setState(() { sideLength == 50 ? sideLength = 100 : sideLength = 50; }); }, ), ), ), ); }