How to make a collectionview respond to pan gestures outside of it's own view

Question

I've got a UICollectionView in my UIViewController and I want it to respond to gestures inside AND outside of the UICollectionView. By default the UICollectionView only responds to the gestures inside its own view but how can I make it respond to swipes outside of its view?

Thanks.

Answer 1

I wrote a view subclass that accomplishes just this:

#import <UIKit/UIKit.h>

@interface TouchForwardingView : UIView

@property (nonatomic, weak) IBOutlet UIResponder *forwardingTarget;

- (instancetype)initWithForwardingTarget:(UIResponder *)forwardingTarget;


@end

#import "TouchForwardingView.h"

@implementation TouchForwardingView

- (instancetype)initWithForwardingTarget:(UIResponder *)forwardingTarget
{
    self = [super init];
    if (self)
    {
        self.forwardingTarget = forwardingTarget;
    }

    return self;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesBegan:touches withEvent:event];
    [self.forwardingTarget touchesBegan:touches withEvent:event];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesEnded:touches withEvent:event];
    [self.forwardingTarget touchesEnded:touches withEvent:event];
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesCancelled:touches withEvent:event];
    [self.forwardingTarget touchesCancelled:touches withEvent:event];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesMoved:touches withEvent:event];
    [self.forwardingTarget touchesMoved:touches withEvent:event];
}

@end

In interface builder, set the subview of the containing view to TouchForwardingView, then assign the collection view to the forwardingTarget property.

Answer 2

Swift version of Nailer's anwer, this will forward all gestures done on the viewcontroller to the collectionview

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    collectionView.touchesBegan(touches, withEvent: event)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    collectionView.touchesEnded(touches, withEvent: event)
}
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
    collectionView.touchesCancelled(touches, withEvent: event)
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
    collectionView.touchesMoved(touches, withEvent: event)
}