error and can't swipe and white while init #19
Description
[ERROR:flutter/shell/common/shell.cc(181)] Dart Error: Unhandled exception:
E/flutter (29329): NoSuchMethodError: The method '>' was called on null.
E/flutter (29329): Receiver: null
E/flutter (29329): Tried calling: >(411428571428.5715)
E/flutter (29329): #0 Object.noSuchMethod (dart:core/runtime/libobject_patch.dart:48:5)
E/flutter (29329): #1 double.< (dart:core/runtime/libdouble.dart:65:18)
E/flutter (29329): #2 double.<= (dart:core/runtime/libdouble.dart:78:37)
E/flutter (29329): #3 PageScrollPhysics.createBallisticSimulation (package:flutter/src/widgets/page_view.dart:366:45)
E/flutter (29329): #4 ScrollPositionWithSingleContext.goBallistic (package:flutter/src/widgets/scroll_position_with_single_context.dart:147:43)
E/flutter (29329): #5 DrivenScrollActivity._end (package:flutter/src/widgets/scroll_activity.dart:634:15)
E/flutter (29329): #6 _RootZone.run (dart:async/zone.dart:1374:54)
E/flutter (29329): #7 _FutureListener.handleWhenComplete (dart:async/future_impl.dart:153:18)
E/flutter (29329): #8 Future._propagateToListeners.handleWhenCompleteCallback (dart:async/future_impl.dart:612:39)
E/flutter (29329): #9 Future._propagateToListeners (dart:async/future_impl.dart:668:37)
E/flutter (29329): #10 Future._completeWithValue (dart:async/future_impl.dart:486:5)
E/flutter (29329): #11 Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:516:7)
E/flutter (29329): #12 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
E/flutter (29329): #13 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
I/flutter (29329): Another exception was thrown: NoSuchMethodError: The method '<=' was called on null.
I/chatty (29329): uid=10517(com.yimaguquan) 2.ui identical 17 lines
I/flutter (29329): Another exception was thrown: NoSuchMethodError: The method '<=' was called on null.
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel unknown, v0.8.3, on Mac OS X 10.12.6 16G29, locale zh-Hans-CN)
[✓] Android toolchain - develop for Android devices (Android SDK 28.0.2)
[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
[✓] Android Studio
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
[✓] Android Studio (version 3.1)
[✓] IntelliJ IDEA Ultimate Edition (version 2017.1.4)
[✓] Connected devices (1 available)
• No issues found!