title: How to create a round CheckBox in Flutter ? Or change the CheckBox's style , such as selected image in Flutter?
body: <p>I want to create a round CheckBox like this </p>
  
  <p><a href="https://i.stack.imgur.com/bGgyE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/bGgyE.png" alt="enter image description here"></a></p>
  
  <p>I've tried multiple variations of this, but none of them seem to work. Including I tried to use ClipRRect . </p>
  
  <p>Because there are more code, I only select part of it to show here.</p>
  
  <pre><code>new Row(
        children: &lt;Widget&gt;[
          //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)
                ),
              )
          ),
  
        ],
      ),
  </code></pre>
  
  <p>I am new to Flutter.Thanks in advance. </p>