Unresolved inclusion in OpenCV+Android tutorial

Hi, I have followed the tutorial to run the mixed native code and java, installed the ndk stuff, and it works nicely. But in the files at jni directory the Eclipse always show a "Unresolved inclusion: " and other unresolved messages like as "Unresolved inclusion: ". I have searched on the net, and says that I should include, in c/c++ properties. But the tutorial examples of OpenCV+Android are not c++ projects. C/C++ perspective does not apply to these projects and I don't find in any place of Eclipse how to include, even switching to c/c++ perspective. I have the plugin cdt installed. How I could handle it? Thanks!