相关疑难解决方法(0)

升级到 flutter 3.0.0 后，运行应用程序时开始出现问题，

（该应用程序可以运行，但终端中出现错误（警告））。

这似乎是一个绑定问题。

错误（警告）说：\n警告：null 感知操作 \'!\' 的操作数具有类型 \'WidgetsBinding\'，其中排除 null。

: Warning: Operand of null-aware operation \'!\' has type \'WidgetsBinding\' which excludes null.\n../\xe2\x80\xa6/src/keyboard_visibility.dart:21\n- \'WidgetsBinding\' is from \'package:flutter/src/widgets/binding.dart\' (\'../../../fvm/versions/3.0.0/packages/flutter/lib/src/widgets/binding.dart\').\npackage:flutter/\xe2\x80\xa6/widgets/binding.dart:1\n    WidgetsBinding.instance!.addObserver(this);\n\n                   ^\n: Warning: Operand of null-aware operation \'!\' has type \'WidgetsBinding\' which excludes null.\n../\xe2\x80\xa6/src/keyboard_visibility.dart:37\n- \'WidgetsBinding\' is from \'package:flutter/src/widgets/binding.dart\' (\'../../../fvm/versions/3.0.0/packages/flutter/lib/src/widgets/binding.dart\').\npackage:flutter/\xe2\x80\xa6/widgets/binding.dart:1\n    WidgetsBinding.instance!.removeObserver(this);\n                   ^\n: Warning: Operand of null-aware operation \'!\' has type \'WidgetsBinding\' which excludes null.\n../\xe2\x80\xa6/src/bot_toast_init.dart:15\n- \'WidgetsBinding\' is from \'package:flutter/src/widgets/binding.dart\' (\'../../../fvm/versions/3.0.0/packages/flutter/lib/src/widgets/binding.dart\').\npackage:flutter/\xe2\x80\xa6/widgets/binding.dart:1\n    WidgetsBinding.instance!.addObserver(this);\n                   ^\n: Warning: Operand of null-aware operation \'!\' …

更新 Flutter 3.0 后出现以下编译错误。此错误没有引用我的代码。它指的是框架。

Launching lib/main.dart on Chrome in debug mode...\nlib/main.dart:1\n: Warning: Operand of null-aware operation '!' has type 'SchedulerBinding' which excludes null.\n../\xe2\x80\xa6/src/framework.dart:275\n- 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../snap/flutter/common/flutter/packages/flutter/lib/src/scheduler/binding.dart').\npackage:flutter/\xe2\x80\xa6/scheduler/binding.dart:1\n    if (SchedulerBinding.instance!.schedulerPhase ==\n