"Cannot run with sound null safety" Flutter 现有项目？

Question

我有一个要修改的现有应用程序，我正在使用以下依赖项：

  path_provider: ^2.0.8
  http: ^0.13.4
  html: ^0.15.0
  custom_pop_up_menu: ^1.2.2
  share: ^2.0.4
  connectivity: ^3.0.6
  flutter_swiper: ^1.1.6

以下错误，我什至创建了一个新的空项目并将 dart 文件添加到该项目，但它现在不起作用。

    Error: Cannot run with sound null safety, because the following dependencies
don't support null safety:

 - package:flutter_swiper
 - package:plugin_platform_interface
 - package:flutter_page_indicator
 - package:transformer_page_view

Answer 1

这是因为您使用的某些 dependencies 不支持空安全，要解决此问题，您可以 upgrade 您的 dependencies 或使用下面的 command 运行你的申请没有 null-safety.

flutter run --no-sound-null-safety

Answer 2

首先将你的 flutter 和包升级到最新，

运行 flutter pub outdated --mode=null-safety 打印所有过时的包。比，
运行这个， flutter pub upgrade --null-safety自动升级所有包

Answer 3

选项 1：升级你的 flutter 和包到最新运行 flutter pub outdated --mode=null-safety 显示所有过时的包。然后，运行 flutter pub upgrade --null-safety 升级所有没有声音的包 null safety

选项 2：运行flutter run --no-sound-null-safety

选项 3：如果你想运行你的应用程序没有健全的空安全，对于 VSCode 用户，将以下内容添加到 settings.json

"dart.flutterRunAdditionalArgs": [
    "--no-sound-null-safety"
],

"Cannot run with sound null safety" Flutter 现有项目？

"Cannot run with sound null safety" Flutter an existing Project?

flutter

dart

dart-null-safety