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?

No, of course I know how to enlarge frame of view :) I need to enlarge hit frame, without affecting its real frame. — Tesseract, Mar 21 '13 at 17:14

score 24 · Accepted Answer · answered Mar 21 '13 at 17:17

24

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.

answered Mar 21 '13 at 17:17

rmaddy

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I think it is better to override pointInside because hitTest calls pointInside: recursively on subviews. – pronebird Nov 25 '15 at 12:35

score 6 · Answer 2 · answered Jan 12 '18 at 14:07

6

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;
}

answered Jan 12 '18 at 14:07

Marcin Mierzejewski

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score 3 · Answer 3 · edited May 23 '17 at 12:01

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

edited May 23 '17 at 12:01

Community

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answered Jan 24 '17 at 16:57

Sir Codesalot

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Error: Declarations in extensions can't override yet – Matthew Barker Mar 25 '18 at 05:57
@MatthewBarker see answer here: https://stackoverflow.com/questions/44616409/declarations-in-extensions-cannot-override-yet-error-in-swift-4 – Sir Codesalot Mar 25 '18 at 06:51

How to enlarge hit area of UIGestureRecognizer?

3 Answers3

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