Detect view change on ViewPager

I am implementing a horizontally by library ViewPager ViewPagerExtensions (com.astuetz.viewpager.extensions) by SwipeyTabsAdapter. Is there anyway to intercept when a change of view? in the same way, i could know in what view is the user at all times? The code of ViewPager ``` public class DiccionariuPagerAdapter extends PagerAdapter { protected transient Activity mContext; private int mLength = 0; public DiccionariuPagerAdapter(Activity context, int length) { mContext = context; mLength = length; } @Override public int getCount() { return mLength; } @Override public Object instantiateItem(View container, int position) { RelativeLayout v = new RelativeLayout(mContext); View vi; // Creating an instance for View Object LayoutInflater inflater = (LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); if (position == 0) { vi = inflater.inflate(R.layout.diccionariu, null); } else if (position == 1) { vi = inflater.inflate(R.layout.conxugar, null); } else { vi = inflater.inflate(R.layout.traducir, null); } v.addView(vi); //v.addView(t); ((ViewPager) container).addView(v, 0); startUpdate(container); return v; } @Override public void destroyItem(View container, int position, Object view) { ((ViewPager) container).removeView((View) view); } @Override public boolean isViewFromObject(View view, Object object) { return view == ((View) object); } @Override public void finishUpdate(View container) {} @Override public void restoreState(Parcelable state, ClassLoader loader) {} @Override public Parcelable saveState() { return null; } @Override public void startUpdate(View container) {} } ``` thank you very much