Ios 我如何确保用户继续他们在应用程序中停止的地方

您可以使用sharedPference来存储和检索LastLeftOverPageIndex. You can download the library from here个

当用户退出应用程序时，必须保存当前页码，或者使用停用方法导航到不同的屏幕，并使用initState方法进入屏幕时恢复存储的先前存储的索引；

我已经修改了你的代码

class BookDemo extends StatefulWidget {
  const BookDemo({super.key});

  @override
  State<BookDemo> createState() => _BookDemoState();
}

class _BookDemoState extends State<BookDemo> {
  final _controller = GlobalKey<PageFlipWidgetState>();

  // sharedPreferences to store lastLeftOverPage Index
  final Future<SharedPreferences> _prefs = SharedPreferences.getInstance();

  // last left over page index
  int lastLeftOverPageIndex = 0;

  // SharedPreference key to retrieve the  value of lastLeftOverPageIndex
  String lastLeftOverPageNoPrefKey = "_lastLeftOverPageNoPrefKey";

  final List<String> imagesPath = [
    "assets/images/image_1.png",
    "assets/images/image_2.png",
    "assets/images/image_3.png"
  ];

  Widget _buildDemoPage(String imagePath) {
    return Scaffold(
      body: Image.asset(
        imagePath,
        fit: BoxFit.cover,
      ),
    );
  }

  @override
  void initState() {
    // restore the previous lastLeftOverPageIndex;
    _restoreLeftOverPage();
    super.initState();
  }

  Future<void> _restoreLeftOverPage() async {
    SharedPreferences pref = await _prefs;
    lastLeftOverPageIndex =
        pref.getInt(lastLeftOverPageNoPrefKey)?.toInt() ?? 0;
    // navigate the book page index to lastLeftOverPageIndex
    _controller.currentState?.goToPage(lastLeftOverPageIndex);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: PageFlipWidget(
        key: _controller,
        backgroundColor: Colors.white,
        initialIndex: lastLeftOverPageIndex,
        lastPage: Container(
            color: Colors.white, child: const Center(child: Text('The End!'))),
        children: [
          for (var imagePath in imagesPath) _buildDemoPage(imagePath),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        child: const Icon(Icons.looks_one_outlined),
        onPressed: () {
          _controller.currentState?.goToPage(1);
        },
      ),
    );
  }

  @override
  void dispose() {
    super.dispose();
  }

  @override
  void deactivate() {
// before disposing the widget save the current page no
    var currentPageNo = _controller.currentState?.pageNumber.toInt() ?? 0;
    saveLastLeftOverPaqePref(currentPageNo);
  }

  Future<void> saveLastLeftOverPaqePref(var lastPage) async {
    SharedPreferences pref = await _prefs;
    pref.setInt(lastLeftOverPageNoPrefKey, lastPage);
  }
}

如果我的回答对你有效，别忘了做个记号.