I am using CardView of support library in my android app. I tried 4-5 hours to resolve this but i could not get success.
I have added CardView
I had the same problem as you.
In Eclipse, when you import cardview from directory \sdk\extras\android\support\v7\cardview follow the steps that are commented in "Adding libraries with resources -> Eclipse" in the official documentation:
https://developer.android.com/intl/es/tools/support-library/setup.html#libs-with-res
Before adding cardview as library to your project, go to "Properties -> Android" of cardview project and add the android-support-v7-appcompat library. Don't forget check "IsLibrary".
Now, you can add cardview as library to your project. Clean both projects to refresh the changes.
I hope it helps you.