pls How can I import classes in Android eclipse on Ubuntu OS

The easiest way is to write the class name correctly and then hover above the name with your pointed. The eclipse will give you class suggestions based on the name you wrote then click on the class you want for it to be imported.

Or

You can write it manually.
Example:
import android.content.Activity

This is not dependent on Ubuntu OS

lordZOUGA:
The easiest way is to write the class name correctly and then hover above the name with your pointed. The eclipse will give you class suggestions based on the name you wrote then click on the class you want for it to be imported.

Or

You can write it manually.
Example:
import android.content.Activity

This is not dependent on Ubuntu OS

You said it all
@op please switch to android studio if you can, its far better and fast too