How to enlarge hit area of UIGestureRecognizer?

Question

I'm using few gesture recognizers on some views, but sometimes views are too small and it's hard to hit it. Using recognizers is necessary, so how can I enlarge hit area?

Answer 1

If you are doing this for a custom UIView , you should be able to override the hitTest:withEvent: method:

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    CGRect frame = CGRectInset(self.bounds, -20, -20);

    return CGRectContainsPoint(frame, point) ? self : nil;
}

The above code will add a 20 point border around the view. Tapping anywhere in that area (or on the view itself) will indicate a hit.

Answer 2

Swift version of @rmaddy answer:

override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
    let frame = self.bounds.insetBy(dx: -20, dy: -20);
    return frame.contains(point) ? self : nil;
}

Answer 3

If you're using a UIImageView as a button, you can use the following extension (Swift 3.0):

extension UIImageView {
open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
    if self.isHidden || !self.isUserInteractionEnabled || self.alpha < 0.01 { return nil }

    let minimumHitArea = CGSize(width: 50, height: 50)
    let buttonSize = self.bounds.size
    let widthToAdd = max(minimumHitArea.width - buttonSize.width, 0)
    let heightToAdd = max(minimumHitArea.height - buttonSize.height, 0)
    let largerFrame = self.bounds.insetBy(dx: -widthToAdd / 2, dy: -heightToAdd / 2)

    // perform hit test on larger frame
    return (largerFrame.contains(point)) ? self : nil
}
}

Similar to the UIButton extension here