You need to change the nature of the project (this has already been answered, but nobody gave the actual string you need for that.)
- Close eclipse
- Open the .project file in your project
-
Make the natures section look like:
<natures> <nature>com.android.ide.eclipse.adt.AndroidNature</nature> <nature>org.eclipse.jdt.core.javanature</nature> </natures>
Start eclipse again, have fun.
Note: If you are using maven you can configure the project’s nature in your pom, see the maven eclipse plugin doc