SliverPersistentHeader设置pinned为true之后不跟随总体下拉

[Dabbit-Chan]

我想让黄色pinWidget和底下的list一起往下，但是只有list往下了，pinWidget还在顶上，结果就是refresh的header会在pinWidget上出现。

import 'package:easy_refresh/easy_refresh.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with AutomaticKeepAliveClientMixin {
  final SliverOverlapAbsorberHandle handle1 = SliverOverlapAbsorberHandle();
  final SliverOverlapAbsorberHandle handle2 = SliverOverlapAbsorberHandle();
  final SliverOverlapAbsorberHandle handle3 = SliverOverlapAbsorberHandle();

  @override
  bool get wantKeepAlive => true;

  @override
  Widget build(BuildContext context) {
    super.build(context);
    return DefaultTabController(
      length: 2,
      child: Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: NestedScrollView(
          // pinnedHeaderSliverHeightBuilder: () => 60,
          // onlyOneScrollInBody: true,
          headerSliverBuilder: (context, innerBoxIsScrolled) {
            return [
              SliverToBoxAdapter(child: _headerCard()),
              _pinWidget(Colors.orange, 60),
            ];
          },
          body: TabBarView(
            children: [
              EasyRefresh.builder(
                onRefresh: () {},
                childBuilder: (context, physics) {
                  return CustomScrollView(
                    physics: physics,
                    slivers: [
                      _pinWidget(Colors.yellow, 30),
                      SliverFixedExtentList(
                        itemExtent: 50,
                        delegate: SliverChildBuilderDelegate(
                              (context, index) {
                            return ListTile(title: Text('$index'));
                          },
                          childCount: 30,
                        ),
                      ),
                    ],
                  );
                },
              ),
              EasyRefresh.builder(
                onRefresh: () {},
                childBuilder: (context, physics) {
                  return CustomScrollView(
                    physics: physics,
                    slivers: [
                      _pinWidget(Colors.green, 30),
                      SliverFixedExtentList(
                        itemExtent: 50,
                        delegate: SliverChildBuilderDelegate(
                              (context, index) {
                            return ListTile(title: Text('-$index'));
                          },
                          childCount: 30,
                        ),
                      ),
                    ],
                  );
                },
              ),
            ],
          ),
        ), // This trailing comma makes auto-formatting nicer for build methods.
      ),
    );
  }

  Widget _headerCard() {
    return Container(height: 100, color: Colors.red);
  }

  Widget _pinWidget(Color color, double height) {
    return SliverPersistentHeader(
      pinned: true,
      delegate: SliverHeaderDelegate.fixedHeight(height: height, child: Container(color: color)),
    );
  }
}

typedef SliverHeaderBuilder = Widget Function(
    BuildContext context, double shrinkOffset, bool overlapsContent);

class SliverHeaderDelegate extends SliverPersistentHeaderDelegate {
  SliverHeaderDelegate({
    required this.maxHeight,
    this.minHeight = 0,
    required Widget child,
  })  : builder = ((a, b, c) => child),
        assert(minHeight <= maxHeight && minHeight >= 0);

  SliverHeaderDelegate.fixedHeight({
    required double height,
    required Widget child,
  })  : builder = ((a, b, c) => child),
        maxHeight = height,
        minHeight = height;

  SliverHeaderDelegate.builder({
    required this.maxHeight,
    this.minHeight = 0,
    required this.builder,
  });

  final double maxHeight;
  final double minHeight;
  final SliverHeaderBuilder builder;

  @override
  Widget build(
      BuildContext context,
      double shrinkOffset,
      bool overlapsContent,
      ) {
    Widget child = builder(context, shrinkOffset, overlapsContent);
    return SizedBox.expand(child: child);
  }

  @override
  double get maxExtent => maxHeight;

  @override
  double get minExtent => minHeight;

  @override
  bool shouldRebuild(SliverHeaderDelegate oldDelegate) {
    return oldDelegate.maxExtent != maxExtent || oldDelegate.minExtent != minExtent;
  }
}

[xuelongqy]

使用HeaderLocator，可以参考示例或者文档注释