Answers for "flutter just icon button"

icon as button flutter

IconButton(
            icon: Icon(
              Icons.directions_transit,
            ),
            iconSize: 50,
            color: Colors.green,
            splashColor: Colors.purple,
            onPressed: () {},
          ),

flutter raised button with icon

FlatButton.icon(onPressed: null, icon: null, label: null);
RaisedButton.icon(onPressed: null, icon: null, label: null);