TextField(
              decoration: new InputDecoration(
                focusedBorder: OutlineInputBorder(
                  borderSide: BorderSide(color: Colors.greenAccent, width: 5.0),
                ),
                enabledBorder: OutlineInputBorder(
                  borderSide: BorderSide(color: Colors.red, width: 5.0),
                ),
                hintText: 'Mobile Number',
              ),