Android onScroll problems

Question

@Override
public boolean onScroll(MotionEvent arg0, MotionEvent arg1, float arg2,
        float arg3) {
    // TODO Auto-generated method stub
    if(arg0.getX()<arg1.getX()&&id!=0x7f020000)
    {
    previousId=id-1;
    imageView.setImageResource(id);
    id++;
    }
    else if(arg0.getX()>arg1.getX()&& id!=0x7f020004)
    {
    imageView.setImageResource(previousId);
    }
    return true;

}

The problem is when I scrolled, the id plus 2 instead 1. I don't understand why. Does someone can explain why? and how to solve it?

Answer 1

onScroll can be called multiple times. If you only want to increment your counter once, you should cache the floats and compare them - if they are different from the cached values, a new scroll has occurred.