How to keep state in the "books" example

[amitrotner]

Hi,

I am trying to add a state keeping ability to the "books" example.
I have followed https://gorouter.dev/nested-navigation#keeping-state and changed author_list.dart so the authors list will be 50 times longer (just for the demonstration) and added AutomaticKeepAliveClientMixin.

// Copyright 2021, the Flutter project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:flutter/material.dart';

import '../data.dart';

class AuthorList extends StatefulWidget {
  const AuthorList({
    required this.authors,
    this.onTap,
    Key? key,
  }) : super(key: key);

  final List<Author> authors;
  final ValueChanged<Author>? onTap;

  @override
  State<AuthorList> createState() => _AuthorListState();
}

class _AuthorListState extends State<AuthorList> with AutomaticKeepAliveClientMixin {
  @override
  Widget build(BuildContext context) {
    super.build(context);
    return ListView.builder(
      itemCount: widget.authors.length * 50,
      itemBuilder: (context, index) => ListTile(
        title: Text(
          widget.authors[index % widget.authors.length].name,
        ),
        subtitle: Text(
          '${widget.authors[index % widget.authors.length].books.length} books',
        ),
        onTap: widget.onTap != null ? () => widget.onTap!(widget.authors[index % widget.authors.length]) : null,
      ),
    );
  }

  @override
  bool get wantKeepAlive => true;
}

However, when I scroll down the authors page, move to another page and return to the authors page, the state is not preserved.

How can I modify this example to enable state preserving?

Thanks

[csells]

Interesting. That sample worked when @rydmike built it. @rydmike thoughts about why it might not be working?