//  CircleAvatar 頭像 alignment和Positioned 不可同時使    用  Positioned(相當于絕對定位 主要應用于多個控件疊加的時候)
  class MyStackWidget extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Center(
    child: Column(
  children: <Widget>[
    Stack(
      // alignment: const FractionalOffset(0.5, 1),
      children: <Widget>[
        new CircleAvatar(
          backgroundImage: new NetworkImage(
              'https://dss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=1671247724,3484152546&fm=26&gp=0.jpg'),
          radius: 100.0,
        ),
        Positioned(
          top: 160,
          left: 70,
          child: Container(
            decoration: new BoxDecoration(
              color: Colors.pink,
            ),
            padding: EdgeInsets.all(10.0),
            child: Text('漂亮MM'),
          ),
        ),
        Positioned(
          top: 10,
          left: 160,
          child: Text(
            'VIP',
            style: TextStyle(
              color: Colors.blue,
              fontSize: 25,
            ),
          ),
        ),
      ],
    ),
  ],
));
}
}

效果圖

代碼內部有解釋