There is an error when importing a new project
The type Java.lang.Class cannot be resolved. It is indirectly referenced from required. class files
And there is no androidx.x folder underneath the item (which contains the jar package)
Solution
Right-click your project name in Package Explorer,
Select Build Path,config build Path,
On the left is a list of Android,
The Android x.x version is displayed in project build target, and a different one, such as android6.0, is selected, and the android6.0 folder is created under the project, which has a jar package
Re-modify back to androidx.x, androidx.x folder will be generated
Open the Project,clean of the menu bar, select your project name, make sure that cleanup deletes the Gen folder, and then automatically rebuilds project (there is a hint in the lower right corner), the Gen folder is regenerated, and the problem is solved