Passing through touches to UIViews underneath

The UIGestureRecognizer is a red herring I think. In the end to solve this I overrode the pointInside:withEvent: method of my UIView:

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
    BOOL pointInside = NO;

    if (CGRectContainsPoint(imageView.frame, point) || expanded) pointInside = YES;

    return pointInside;
}

This causes the view to trap all touches if you touch either the imageView or if its expanded flag is set. If it is not expanded then only trap the touches if they are on the imageView.

By returning NO, the top level VC's View queries the rest of its view hierarchy looking for a hit.

Select your View in Storyboard or XIB and...

Or in Swift

view.isUserInteractionEnabled = false

Look into the UIGestureRecognizerDelegate Protocol. Specifically, gestureRecognizer:shouldReceiveTouch:

You'll want to make each UIGestureRecognizer a property of your UIViewController,

// .h
@property (nonatomic, strong) UITapGestureRecognizer *lowerTap;

// .m
@synthesize lowerTap;

// When you are adding the gesture recognizer to the image view
self.lowerTap = tapGestureRecognizer

Make sure you make your UIViewController a delegate,

[self.lowerTap setDelegate: self];

Then, you'd have something like this,

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
    if (expanded && gestureRecognizer == self.lowerTap) {    
        return NO;
    }
    else {
        return YES;
    }
}

Of course, this isn't exact code. But this is the general pattern you'd want to follow.