Infinity pageView how to use nextPage method?

[liuchuancong]

I have an Infinity PageView,When i use

pageController.nextPage(duration: new Duration(microseconds: 300),curve: Curves.linear);

i received a problem

[ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: 'package:flutter/src/widgets/page_view.dart': Failed assertion: line 97 pos 7: 'positions.isNotEmpty': PageController.page cannot be accessed before a PageView is built with it.

flutter doctor -v

[✓] Flutter (Channel stable, v1.5.4-hotfix.2, on Mac OS X 10.14.5 18F132, locale zh-Hans-CN)
    • Flutter version 1.5.4-hotfix.2 at /Users/duiduikeji/flutter
    • Framework revision 7a4c33425d (9 weeks ago), 2019-04-29 11:05:24 -0700
    • Engine revision 52c7a1e849
    • Dart version 2.3.0 (build 2.3.0-dev.0.5 a1668566e5)

 
[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
    • Android SDK at /Users/duiduikeji/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-28, build-tools 28.0.3
    • ANDROID_HOME = /Users/duiduikeji/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
    • All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 10.2.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 10.2.1, Build version 10E1001
    • ios-deploy 1.9.4
    • CocoaPods version 1.7.0.rc.1

[✓] Android Studio (version 3.4)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 36.1.1
    • Dart plugin version 183.6270
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[✓] VS Code (version 1.35.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.1.0

[✓] Connected device (1 available)
    • EML L29 • UBV0218710000805 • android-arm64 • Android 9 (API 28)

• No issues found!

there is my code

      child: Scaffold(
        body: PageView.custom(
          physics: CustomScrollPhysics(),
          scrollDirection: Axis.vertical,
          childrenDelegate: new SliverChildBuilderDelegate(
            (context, index) {
              return FriendsItem(
                key: PageStorageKey(index),
                parentPageController:controller
              );
            },
          ),
        ),
      ),

[BondarenkoStas]

This is a question better suited for StackOverflow, since there doesn’t seem to be anything wrong with Flutter itself. Closing, as this is not an issue report. See https://flutter.dev/community for support options.

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.