CODE EXAMPLE FOR DART

flutter container rounded top corners

Container(
  height: 200.0,
  color: Colors.transparent,
  child: Container(
    decoration:  BoxDecoration(
      color: Colors.red,
      borderRadius: BorderRadius.only(
        topLeft: const Radius.circular(20.0),
        topRight: const Radius.circular(20.0),
      )
    ),
    child: Text("Text ...."),
 ),
),