一天前，我遇到了这样的问题.这可能是您的依赖项中的支持库和androidx之间的冲突.看看此问题.以我为例，我解决了这个问题，从pubspec中的项目中手动删除了所有依赖项，并使用已经使用androidx的新更新版本逐一添加，并且也迁移了我的项目.好吧，我尝试IDE androidX迁移工具，但没有成功.最后，要了解第三部分库，其中一些需要花费一些时间来更新和创建类似的问题.

Man i had a problem like this just one day ago. This is probably conflict between support library and androidx in your dependencies. Take a look at this issue. In my case i solve this manually removing all dependencies from my project in pubspec and add one by one with new updated version that already use androidx and migrate my project too. Well i try IDE androidX migration tool but without success. Finally be aware with thrid part libraries some of them take a time to update and create problems like this.