Flutter 布局参考手册：Stack

Stack

非常适合将 widget 堆叠在一起

@override
Widget build(BuildContext context) {
  Widget main = Scaffold(
    appBar: AppBar(title: Text('Stack')),
  );

  return Stack(
    fit: StackFit.expand,
    children: <Widget>[
      main,
      Banner(
        message: "Top Start",
        location: BannerLocation.topStart,
      ),
      Banner(
        message: "Top End",
        location: BannerLocation.topEnd,
      ),
      Banner(
        message: "Bottom Start",
        location: BannerLocation.bottomStart,
      ),
      Banner(
        message: "Bottom End",
        location: BannerLocation.bottomEnd,
      ),
    ],
  );
}
复制代码

如果您想使用自己的 widget，请将它们放在里面 Placed 如果您不这样做不想猜top或bottom的值，可以使用LayoutBuilder来获取它们

Widget build(BuildContext context) {
  const iconSize = 50;
  return Scaffold(
    appBar: AppBar(title: Text('Stack with LayoutBuilder')),
    body: LayoutBuilder(
      builder: (context, constraints) =>
        Stack(
          fit: StackFit.expand,
          children: <Widget>[
            Material(color: Colors.yellowAccent),
            Positioned(
              top: 0,
              child: Icon(Icons.star, size: iconSize),
            ),
            Positioned(
              top: constraints.maxHeight - iconSize,
              left: constraints.maxWidth - iconSize,
              child: Icon(Icons.call, size: iconSize),
            ),
          ],
        ),
    ),
  );
}

作者：Yuqi
链接：https://juejin.im/post/5cfe0d136fb9a07efc497d7d
来源：掘金
版权归作者所有。商业转载请联系作者获得批准。非商业转载请注明出处。