change raised button shape flutter code example

Example 1: rounded button flutter

FlatButton(
              color: Colors.red,
              shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(18.0)),
              child: new Text('round button'),
              onPressed: () {},
            ),

Example 2: A circuler border button in flutter

Padding(  padding: EdgeInsets.only(left: 150.0, right: 0.0),  child: RaisedButton(    textColor: Colors.white,    color: Colors.black,    child: Text("Search"),    onPressed: () {},    shape: new RoundedRectangleBorder(      borderRadius: new BorderRadius.circular(30.0),    ),  ),)