title: Detect view change on ViewPager
body: <p>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?</p>
  
  <p>The code of ViewPager</p>
  
  <pre><code>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) {}
  
  }
  </code></pre>
  
  <p>thank you very much</p>