SpeedScrollListener.java

package com.cuubonandroid.sugaredlistanimations;

import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;

/**
 * 
 * @author <a href="http://www.hugofernandes.pt">Hugo Fernandes</a>
 * 
 */
public class SpeedScrollListener implements OnScrollListener {

  private int previousFirstVisibleItem = 0;
  private long previousEventTime = 0, currTime, timeToScrollOneElement;
  private double speed = 0;

  @Override
  public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
    if (previousFirstVisibleItem != firstVisibleItem) {
      currTime = System.currentTimeMillis();
      timeToScrollOneElement = currTime - previousEventTime;
      speed = ((double) 1 / timeToScrollOneElement) * 1000;

      previousFirstVisibleItem = firstVisibleItem;
      previousEventTime = currTime;

    }
  }

  @Override
  public void onScrollStateChanged(AbsListView view, int scrollState) {
  }

  public double getSpeed() {
    return speed;
  }

}