由于deviceType没有被传递到ListItems类中的Sizer小部件中。因此尝试提供设备类型或从Sizer小部件中删除设备参数。

class ListItems extends StatelessWidget {
  final String child;

  const ListItems({Key? key, required this.child}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Sizer(
      builder: ((context, orientation, [deviceType = DeviceType.mobile]) {
        return Padding(
          padding: const EdgeInsets.all(8.0),
          child: ConstrainedBox(
            constraints: const BoxConstraints(
              minHeight: 100,
              maxHeight: 100,
            ),
            child: Container(
              color: Colors.blueGrey,
              child: Center(child: Text(child)),
            ),
          ),
        );
      }),
    );
  }
}