“Unknown artifact. Not resolved or indexed” error

问题:

I'm trying to modify the build.sbt file to add scalatest dependencies in IntelliJ IDEA. There's no error log in the console but I got a Unknown artifact. Not resolved or indexed. when I hovered my mouse over the underline. How do I solve this? Many thanks in advance!

This is the line I used to add dependency: libraryDependencies += "org.scalatest" % "scalatest_2.11" % "3.0.1" % "test"

And here is what my screen looks like:

回答1:

If you just added the dependency, it might not have been downloaded yet. Refresh/reimport the project to do so.

If it has already been downloaded, press Alt+Enter in IntelliJ on the lines with the warning and select the "update project resolvers' indexes" quickfix, then select the "local cache" index and click "update".

You can verify that the update worked by checking the date in the "Updated" column:

回答2:

I had the same problem. File -> Invalidate Caches/Restart... fixed the issue for me.
Just updating/refreshing project didn't work in my case.

回答3:

In my situation, I tried:

1. Alt + Enter then Refresh Project.
2. Update Resolvers' Local cache.
3. File -> Invalidate Caches/Restart.

None of the above worked. So for future reference, here is my solution for this issue:

4. Ensure Maven Integration plugin is enabled, and instead of updating Resolvers's Local cache, update the public which is Never Updated.

This process may take some time to finish download if it's a newly installed IntelliJ IDEA.