Locking UIPanGestureRecognizer to a certain direction

Question

I have UIPanGestureRecognizer and I'm trying to get it only swipe in one direction (up). I haven't been able to find a solution that works. Thanks. This is my current code:

- (void)panGesture:(UIPanGestureRecognizer *)recognizer{

CGPoint t = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x + t.x, recognizer.view.center.y + t.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];

}

Answer 1

- (void)panGesture:(UIPanGestureRecognizer *)recognizer {
    CGPoint t = [recognizer translationInView:self.view];

    if (t.y < 0) {
        t = CGPointMake(0, t.y);
    }
    else {
        t = CGPointMake(0, 0); // look at this
    }

    recognizer.view.center = CGPointMake(recognizer.view.center.x + t.x,
                                         recognizer.view.center.y + t.y);

    [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}

To be able to drag up and down use CGPointMake(0, t.y); instead of my if