import 'package:flutter/cupertino.dart';

class CustomSliverPersistentHeaderDelegate extends SliverPersistentHeaderDelegate {
   final Widget child;

   CustomSliverPersistentHeaderDelegate({required this.child});

   @override
   double get minExtent => 50.0; // 最小高度

   @override
   double get maxExtent => 50.0; // 最大高度

   @override
   Widget build(BuildContext context, double shrinkOffset, bool overlapsContent) {
     return child;
   }

   @override
   bool shouldRebuild(covariant SliverPersistentHeaderDelegate oldDelegate) {
     return true;
   }

}