sliver_main_axis_group_issue.dart

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(home: DemoPageWithMainAxisGroup());
    // return MaterialApp(home: DemoPageWithoutMainAxisGroup());
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        bottom: false,
        child: CustomScrollView(
          slivers: [
            SliverMainAxisGroup(
              slivers: [
                SliverPersistentHeader(
                  pinned: true,
                  delegate: MySliverPersistentHeaderDelegate(),
                ),
                MyItemList(),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        bottom: false,
        child: CustomScrollView(
          slivers: [
            SliverPersistentHeader(
              pinned: true,
              delegate: MySliverPersistentHeaderDelegate(),
            ),
            MyItemList(),
          ],
        ),
      ),
    );
  }
}

class MySliverPersistentHeaderDelegate extends SliverPersistentHeaderDelegate {
  @override
  Widget build(
    BuildContext context,
    double shrinkOffset,
    bool overlapsContent,
  ) {
    return Container(
      color: Colors.orange,
      alignment: Alignment.center,
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 20.0),
        child: TextField(
          decoration: InputDecoration(hintText: 'Search...'),
          onTapUpOutside: (_) => FocusScope.of(context).unfocus(),
        ),
      ),
    );
  }

  @override
  double get maxExtent => 64.0;

  @override
  double get minExtent => 64.0;

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

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

  @override
  Widget build(BuildContext context) {
    return SliverList(
      delegate: SliverChildBuilderDelegate(
        (context, index) => ListTile(
          title: Text('Item #$index'),
          tileColor: Colors.primaries[index % Colors.primaries.length],
        ),
        childCount: 50,
      ),
    );
  }
}