Error parsing XML: unbound prefix on library

Question

I am using three libraries in my project:

a. ViewPager
b. SherlockActionBar
c. PagerSlidingTabStrip

In my layout xml, I am getting the followin

Answer 1

Root element of every xml have to contain:

xmlns:android="http://schemas.android.com/apk/res/android"

And you can use android attributes after.