A null check operator error caused a crash | 一个判定空值的符号错误导致了程序无法编译成功

[lilpard-mk]

When I was openning my build App, the App board was totally blank, and the error info is below:

Debug service listening on ws://127.0.0.1:50935/nmjD2HWXneA=/ws
Syncing files to device macOS...
[ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Null check operator used on a null value
#0 new BotToastWidgetsBindingObserver._ (package:bot_toast/src/bot_toast_init.dart:15:28)
#1 BotToastWidgetsBindingObserver._singleton (package:bot_toast/src/bot_toast_init.dart:21:38)
#2 BotToastWidgetsBindingObserver._singleton (package:bot_toast/src/bot_toast_init.dart)
#3 BotToastInit (package:bot_toast/src/bot_toast_init.dart:49:34)
#4 main (package:new_flutter_app/main.dart:86:14)
#5 _runMainZoned.. (dart:ui/hooks.dart:146:25)
#6 _rootRun (dart:async/zone.dart:1354:13)
#7 _CustomZone.run (dart:async/zone.dart:1258:19)
#8 _runZoned (dart:async/zone.dart:1789:10)
#9 runZonedGuarded (dart:async/zone.dart:1777:12)
#10 _runMainZoned. (dart:ui/hooks.dart:139:5)
#11 _delayEntrypointInvocation. (dart:isolate-patch/isolate_patch.dart:283:19)
#12 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

Then I changed the null check operator '!' to '?' on 'bot_toast/src/bot_toast_init.dart:15:28' , and then everything is just fine.

Wish this bug would be fixed in future.

[MMMzq]

你可以试试下面这种方式或者升级Flutter:

void main() {
  WidgetsFlutterBinding.ensureInitialized(); //添加这行
  runApp(MyApp());
}

[lilpard-mk]

已更改，flutter是最新版，目前一切正常，感谢回复！！！