[Swiper] ScrollPosition.viewportDimension 为空报错

[BigTimo]

[ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Null check operator used on a null value
E/flutter (24234): #0 ScrollPosition.viewportDimension (package:flutter/src/widgets/scroll_position.dart:175:53)
E/flutter (24234): #1 _PagePosition.getPixelsFromPage (package:flutter/src/widgets/page_view.dart:382:19)
E/flutter (24234): #2 PageController.animateToPage (package:flutter/src/widgets/page_view.dart:197:16)
E/flutter (24234): #3 _SwiperState.animateToPage (package:flukit/src/swiper.dart:447:11)
E/flutter (24234): #4 _SwiperState._start. (package:flukit/src/swiper.dart:408:7)
E/flutter (24234): #5 _rootRunUnary (dart:async/zone.dart:1436:47)
E/flutter (24234): #6 _CustomZone.runUnary (dart:async/zone.dart:1335:19)
E/flutter (24234): #7 _CustomZone.runUnaryGuarded (dart:async/zone.dart:1244:7)
E/flutter (24234): #8 _CustomZone.bindUnaryCallbackGuarded. (dart:async/zone.dart:1281:26)
E/flutter (24234): #9 _rootRunUnary (dart:async/zone.dart:1444:13)
E/flutter (24234): #10 _CustomZone.runUnary (dart:async/zone.dart:1335:19)
E/flutter (24234): #11 _CustomZone.bindUnaryCallback. (dart:async/zone.dart:1265:26)
E/flutter (24234): #12 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:395:19)
E/flutter (24234): #13 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:426:5)
E/flutter (24234): #14 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

[GraceJoJo]

i met the same error when use "_tabController?.index =index;", if u see the comment ,can you share your solution for this error, i am looking forward your response.