material flutter shape rounded corners code example

Example: flutter squared avatar rounded borders

ClipRRect(
  borderRadius: BorderRadius.circular(20.0),//or 15.0
  child: Container(
    height: 70.0,
    width: 70.0,
    color: Color(0xffFF0E58),
    child: Icon(Icons.volume_up, color: Colors.white, size: 50.0),
  ),
),