How to create a round CheckBox in Flutter ? Or change the CheckBox's style , such as selected image in Flutter?

I want to create a round CheckBox like this

I've tried multiple variations of this, but none of them seem to work. Including I tried to use ClipRRect .

Because there are more code, I only select part of it to show here.

new Row(
      children: <Widget>[
        //new ClipRRect(
        // borderRadius: BorderRadius.all(Radius.circular(90.0)),
        //  child:
          new Checkbox(
              tristate: true,
              value: true,
              onChanged: (bool newValue){
                setState(() {

                });
              },
            activeColor: Color(0xff06bbfb),
          ),
       // ),

        new Expanded(
            child: new Text('将此手机号码和QQ号绑定，提高账号安全性。',
              style: new TextStyle(
                  color: Color(0xff797979)
              ),
            )
        ),

      ],
    ),

I am new to Flutter.Thanks in advance.