What is it?
===========
A subclass of UIGestureRecognizer to implement Swipe gesture on a UIScrollView.

Why?
====
Cuz UISwipeGestureRecognizer is ignored on a UIScrollView when the ContentSize is greater than its frame.width.

How to use?
===========
1)Import: UISwipe4ScrollGestureRecognizer.h
2)Assuming that _scroll is an UIScrollView...

UISwipe4ScrollGestureRecognizer *swipe;
swipe = [[UISwipe4ScrollGestureRecognizer alloc] initWithTarget:self action:@selector(tocoto:)];
[_scroll addGestureRecognizer:swipe];
[swipe release];

You can set the number of touches to trigger it or the direction of the swipe:
[swipe setDirection:UISwipeGestureRecognizerDirectionRight];
[swipe setMinimumNumberOfTouches:2];

Even the velocity of the gesture:
[swipe setSwipeVelocityInView:100.0];

How can I know the direction of the swipe?
==========================================

In your defined callback (in the example our callback method was "tocoto"), you can read the direction of the swipe like this:

-(void)tocoto:(UISwipe4ScrollGestureRecognizer *)recognizer
{
    if (recognizer.direction == UISwipeGestureRecognizerDirectionRight) NSLog(@"right");
    if (recognizer.direction == UISwipeGestureRecognizerDirectionLeft) NSLog(@"left");
    [self doMoreActions];
}