flutter 。如何在 Sliver 中使用 SliverPersistentHeaderDelegate 管理状态？

Question

我将 CustomScrollView 与 Sliver 一起使用。在 header 中，我有一些带有自动完成功能的文本字段(在数据库中搜索数据)，当输入文本等于某个值时，我需要做一些事情。我尝试使用 SliverPersistentHeader。但它不能设置状态。如何设置状态？

The declaration setState() isn't referenced

怎么了？

class MySliverAppBar extends SliverPersistentHeaderDelegate {
  final double expandedHeight;
  MySliverAppBar({@required this.expandedHeight});

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return
      StatefulBuilder(
        builder:(BuildContext context, StateSetter setState) {
          return Stack(
            overflow: Overflow.visible,
            children: [
              SizedBox(
                height: 200,
                child: AppBar(
                  backgroundColor: Colors.green,
                  leading: IconButton(
                    icon: Icon(Icons.menu),
                    onPressed: () {},
                  ),
                  elevation: 0.0,
                ),
              ),
              RaisedButton(
                child: Text("Press"),
                color: Colors.yellow,
                onPressed: (){
                  setState(){
                    // The declaration setState() isn't referenced

                  }
                },),
            ],
          );
        }
      );
  }

  @override
  double get maxExtent => expandedHeight;

  @override
  double get minExtent => kToolbarHeight;

  @override
  bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) => true;
}

Answer 1

尝试在 :

上使用它

StatefulBuilder(
            builder:(BuildContext context, StateSetter setState) {
return //Whatever you want to use here ();
},
),

如果它不起作用请评论。