问 未处理的异常ScrollController未附加到任何滚动视图

EN

调用 PageView 时， _pageController.animateToPage 还没有准备好

您可以使用 addPostFrameCallback 并检查 _pageController.hasClients

代码段

@override
void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      Timer.periodic(Duration(seconds: 4), (Timer timer) {
        if (_currentPage < 3) {
          _currentPage++;
        } else {
          _currentPage = 0;
        if(_pageController.hasClients) {
          _pageController.animateToPage(
            _currentPage,
            duration: Duration(milliseconds: 400),
            curve: Curves.easeInCubic,
}

模拟这种情况的工作演示

​

​

全测试代码

import 'package:flutter/material.dart';
import 'dart:async';
class Feature {
  String name;
  Color color;
  String header;
  String subHeader;
  String imgUrl;
  Feature({this.name, this.color, this.header, this.subHeader, this.imgUrl});
List<Feature> featuredList = [
  Feature(
      name: "a",
      color: Colors.pink,
      header: "ah",
      subHeader: "a sub",
      imgUrl: "https://picsum.photos/250?image=9"),
  Feature(
      name: "b",
      color: Colors.blue,
      header: "bh",
      subHeader: "b sub",
      imgUrl: "https://picsum.photos/250?image=10"),
  Feature(
      name: "c",
      color: Colors.yellow,
      header: "ch",
      subHeader: "c sub",
      imgUrl: "https://picsum.photos/250?image=11")
class WidgetFeatured extends StatefulWidget {
  @override
  _WidgetFeaturedState createState() => _WidgetFeaturedState();
class _WidgetFeaturedState extends State<WidgetFeatured> {
  int _currentPage = 0;
  final PageController _pageController = PageController(
    initialPage: 0,
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      Timer.periodic(Duration(seconds: 4), (Timer timer) {
        if (_currentPage < 3) {
          _currentPage++;
        } else {
          _currentPage = 0;
        if(_pageController.hasClients) {
          _pageController.animateToPage(
            _currentPage,
            duration: Duration(milliseconds: 400),
            curve: Curves.easeInCubic,
  @override
  void dispose() {
    super.dispose();
    _pageController.dispose();
  _onPageChanged(int index) {
    setState(() {
      _currentPage = index;
  @override
  Widget build(BuildContext context) {
    return Container(
      height: 200,
      child: PageView.builder(
        physics: BouncingScrollPhysics(),
        scrollDirection: Axis.horizontal,
        controller: _pageController,
        onPageChanged: _onPageChanged,
        itemBuilder: (context, index) => WidgetFeaturedItem(index),
        itemCount: featuredList.length,
class WidgetFeaturedItem extends StatelessWidget {
  final int indexItem;
  WidgetFeaturedItem(this.indexItem);
  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(20),
      color: featuredList[indexItem].color,
      width: double.infinity,
      height: 180,
      child: Stack(
        children: <Widget>[
            children: <Widget>[
              Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  Text(
                    featuredList[indexItem].header,
                    style: TextStyle(
                      fontSize: 20,
                      fontWeight: FontWeight.bold,
                      color: Colors.white,
                  Text(
                    featuredList[indexItem].subHeader,
                    style: TextStyle(
                      fontSize: 16,
                      fontWeight: FontWeight.bold,
                      color: Colors.white,
                  FlatButton(
                    onPressed: () {},
                    padding: const EdgeInsets.symmetric(
                      horizontal: 15,
                      vertical: 3,
                    color: Theme.of(context).primaryColor,
                    child: Text(
                      'Order now',
                      style: TextStyle(
                        color: Colors.white,
                        fontSize: 12,
                        fontWeight: FontWeight.w100,
              Image.network(
                featuredList[indexItem].imgUrl,
                height: 120,
                width: 120,
                //width: 335,
                fit: BoxFit.cover,
void main() {
  runApp(MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      home: MyHomePage(title: 'Flutter Demo Home Page'),
class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;
  @override
  _MyHomePageState createState() => _MyHomePageState();
class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  void _incrementCounter() {
    setState(() {
      _counter++;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(child: WidgetFeatured()),
            Text(
              'You have pushed the button this many times:',
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,