An imported Android item appears with a red exclamation mark

The import package exists in the cause project, and after the project is imported, the package path that classpath points to has an error that requires a re-bulidpath

"Workaround" Right-click the project name buildpath-> Configure Build Path, and then there are several tabs above to find the package with the Red Cross in libraries as the path error. Modify the current path of the corresponding package to Classpath, which is the path to your SDK. And then go back to eclipse. F5 Refresh Project

"Note" If there is an error, it is the Android SDK version error

An imported Android item appears with a red exclamation mark