use round border in flutter code example

Example 1: flutter container rounded corners

Container(
  decoration: BoxDecoration(
    border: Border.all(
      color: Colors.red[500],
    ),
    borderRadius: BorderRadius.all(Radius.circular(20))
  ),
  child: ...
)

Example 2: rounded raisedbutton in flutter

RaisedButton(
                onPressed: () {},
                color: Colors.amber,
                shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(10)),
                child: Text("Click This"),
              )

Example 3: column round border flutter

Container(
  decoration: BoxDecoration(
    border: Border.all(
      color: Colors.red[500],
    ),
    color: Colors.green[500],
    borderRadius: BorderRadius.all(Radius.circular(20))
  ),
  child: ...
)