JazzyViewpager Not working Properly

[rizvan]

I added library , xml block for jazzypager like this :
<com.jfeinstein.jazzyviewpager.JazzyViewPager
android:id="@+id/viewpager"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />

Added Code in Main activity

JazzyViewPager viewPager = (JazzyViewPager)findViewById(R.id.viewpager);

Then transition effect :
viewPager.setTransitionEffect(TransitionEffect.); ( - any effect)
yet my pages working normally .

[abhishekagarwal]

Have you implemented the instantiateItem(ViewGroup container, final int position) method in the adapter

[rizvan]

Yes i did but its java.lang.NullPointerException exception if i do .
Here's the code :
public JazzyViewPager viewPager;
public Object instantiateItem(ViewGroup container, final int position) {
Object obj = super.instantiateItem(container, position);
viewPager.setObjectForPosition(obj, position);
return obj;
}