CustomScrollView如何定位到类似于SliverToBoxAdapter之类的其他Sliver组件。

[JDongKhan]

您好，有些场景不知道如何使用，能帮忙看一下吗？ 谢谢。

Platforms

Android, iOS

Description

从demo上都在在解决CustomScrollView里面SliverList和SliverGrid的问题，没有看到有关其他sliver组件的解决方案。

My code

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

import 'custom_scrollview_demo_page.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  final ScrollController _scrollController = ScrollController();
  late SliverObserverController observerController;

  void _incrementCounter() {
    // 动画滚动至下标位置
    observerController.animateTo(
      index: 8,
      duration: const Duration(seconds: 1),
      curve: Curves.ease,
    );
  }

  @override
  void initState() {
    observerController = SliverObserverController(controller: _scrollController);
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: SliverViewObserver(
        controller: observerController,
        child: CustomScrollView(
          controller: _scrollController,
          slivers: List.generate(
            10,
            (index) => SliverToBoxAdapter(
              child: GestureDetector(
                onTap: () {
                  Navigator.of(context).push(
                    MaterialPageRoute(
                      builder: (_) => CustomScrollViewDemoPage(),
                    ),
                  );
                },
                child: Container(
                  color: Colors.grey,
                  margin: const EdgeInsets.all(12),
                  child: Text(index.toString()),
                  height: 100,
                ),
              ),
            ),
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

Try do it

这样搞没有效果，还需要额外实现其他方法吗？

[LinXunFeng]

scrollview_observer 没有提供滚动到指定 sliver 位置的功能，不过你可以通过如下代码实现

  final ScrollController _scrollController = ScrollController();
  late SliverObserverController observerController;

  Map<int, BuildContext> _sliverContextMap = {};

  void _incrementCounter() {
    final renderObj = ObserverUtils.findRenderObject(_sliverContextMap[8]);
    if (renderObj is! RenderSliver) return;
    // 动画滚动至下标位置
    _scrollController.animateTo(
      renderObj.constraints.precedingScrollExtent,
      duration: const Duration(seconds: 1),
      curve: Curves.ease,
    );
  }

...

        child: CustomScrollView(
          controller: _scrollController,
          slivers: List.generate(
            10,
            (index) {
              Widget resultWidget = SliverToBoxAdapter(
                child: GestureDetector(
                  onTap: () {
                    Navigator.of(context).push(
                      MaterialPageRoute(
                        builder: (_) => CustomScrollViewDemoPage(),
                      ),
                    );
                  },
                  child: Container(
                    color: Colors.grey,
                    margin: const EdgeInsets.all(12),
                    child: Text(index.toString()),
                    height: 100,
                  ),
                ),
              );
              resultWidget = SliverObserveContext(
                onObserve: (ctx) {
                  _sliverContextMap[index] = ctx;
                },
                child: resultWidget,
              );
              return resultWidget;
            },
          ),
        ),

[JDongKhan]

多谢，我试试。