How to know viewpager is scroll left or right?

set setOnPageChangeListener to your ViewPager

keep a variable global as

private int lastPosition = 0;

and in

@Override
public void onPageSelected(int arg0) {
    if (lastPosition > position) {
         System.out.println("Left");
      }else if (lastPosition < position) {
         System.out.println("Right");
      }
      lastPosition = position;
}