I'm also new to Eclipse, and I've been having a similar problem where Eclipse just won't recognize an import statement, even though all signs point to the dependency having been successfully downloaded.
You should check that your dependency file has actually been downloaded by going to the command line and typing
If you see your package there, then but Eclipse doesn't acknowledge it, the thing that works for me (sometimes) is to go to the terminal, cd into the project folder, and type
Finally refresh project in eclipse
I don't know why this works, and sometimes it doesn't work once, then doing it again does work... so worth a try!