UIButton: Making the hit area larger than the default hit area

Question

Since I am using a background image, none of these solutions worked well for me. Here is a solution that does some fun objective-c magic and offers a drop in solution with minimal code.

First, add a category to UIButton that overrides the hit test and also adds a property for expanding the hit test frame.

UIButton+Extensions.h

@interface UIButton (Extensions)

@property(nonatomic, assign) UIEdgeInsets hitTestEdgeInsets;

@end

UIButton+Extensions.m

#import "UIButton+Extensions.h"
#import <objc/runtime.h>

@implementation UIButton (Extensions)

@dynamic hitTestEdgeInsets;

static const NSString *KEY_HIT_TEST_EDGE_INSETS = @"HitTestEdgeInsets";

-(void)setHitTestEdgeInsets:(UIEdgeInsets)hitTestEdgeInsets {
    NSValue *value = [NSValue value:&hitTestEdgeInsets withObjCType:@encode(UIEdgeInsets)];
    objc_setAssociatedObject(self, &KEY_HIT_TEST_EDGE_INSETS, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

-(UIEdgeInsets)hitTestEdgeInsets {
    NSValue *value = objc_getAssociatedObject(self, &KEY_HIT_TEST_EDGE_INSETS);
    if(value) {
        UIEdgeInsets edgeInsets; [value getValue:&edgeInsets]; return edgeInsets;
    }else {
        return UIEdgeInsetsZero;
    }
}

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
    if(UIEdgeInsetsEqualToEdgeInsets(self.hitTestEdgeInsets, UIEdgeInsetsZero) || !self.enabled || self.hidden) {
        return [super pointInside:point withEvent:event];
    }

    CGRect relativeFrame = self.bounds;
    CGRect hitFrame = UIEdgeInsetsInsetRect(relativeFrame, self.hitTestEdgeInsets);

    return CGRectContainsPoint(hitFrame, point);
}

@end

Once this class is added, all you need to do is set the edge insets of your button. Note that I chose to add the insets so if you want to make the hit area larger, you must use negative numbers.

[button setHitTestEdgeInsets:UIEdgeInsetsMake(-10, -10, -10, -10)];

Note: Remember to import the category (#import "UIButton+Extensions.h") in your classes.

Just set the image edge inset values in interface builder.

Here's an elegant solution using Extensions in Swift. It gives all UIButtons a hit area of at least 44x44 points, as per Apple's Human Interface Guidelines (https://developer.apple.com/ios/human-interface-guidelines/visual-design/layout/)

Swift 2:

private let minimumHitArea = CGSizeMake(44, 44)

extension UIButton {
    public override func hitTest(point: CGPoint, withEvent event: UIEvent?) -> UIView? {
        // if the button is hidden/disabled/transparent it can't be hit
        if self.hidden || !self.userInteractionEnabled || self.alpha < 0.01 { return nil }

        // increase the hit frame to be at least as big as `minimumHitArea`
        let buttonSize = self.bounds.size
        let widthToAdd = max(minimumHitArea.width - buttonSize.width, 0)
        let heightToAdd = max(minimumHitArea.height - buttonSize.height, 0)
        let largerFrame = CGRectInset(self.bounds, -widthToAdd / 2, -heightToAdd / 2)

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

Swift 3:

fileprivate let minimumHitArea = CGSize(width: 100, height: 100)

extension UIButton {
    open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        // if the button is hidden/disabled/transparent it can't be hit
        if self.isHidden || !self.isUserInteractionEnabled || self.alpha < 0.01 { return nil }

        // increase the hit frame to be at least as big as `minimumHitArea`
        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
    }
}

You could also subclass UIButton or a custom UIView and override point(inside:with:) with something like:

Swift 3

override func point(inside point: CGPoint, with _: UIEvent?) -> Bool {
    let margin: CGFloat = 5
    let area = self.bounds.insetBy(dx: -margin, dy: -margin)
    return area.contains(point)
}

Objective-C

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
    CGFloat margin = 5.0;
    CGRect area = CGRectInset(self.bounds, -margin, -margin);
    return CGRectContainsPoint(area, point);
}

Here's Chase's UIButton+Extensions in Swift 3.0.

import UIKit

private var pTouchAreaEdgeInsets: UIEdgeInsets = .zero

extension UIButton {

    var touchAreaEdgeInsets: UIEdgeInsets {
        get {
            if let value = objc_getAssociatedObject(self, &pTouchAreaEdgeInsets) as? NSValue {
                var edgeInsets: UIEdgeInsets = .zero
                value.getValue(&edgeInsets)
                return edgeInsets
            }
            else {
                return .zero
            }
        }
        set(newValue) {
            var newValueCopy = newValue
            let objCType = NSValue(uiEdgeInsets: .zero).objCType
            let value = NSValue(&newValueCopy, withObjCType: objCType)
            objc_setAssociatedObject(self, &pTouchAreaEdgeInsets, value, .OBJC_ASSOCIATION_RETAIN)
        }
    }

    open override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        if UIEdgeInsetsEqualToEdgeInsets(self.touchAreaEdgeInsets, .zero) || !self.isEnabled || self.isHidden {
            return super.point(inside: point, with: event)
        }

        let relativeFrame = self.bounds
        let hitFrame = UIEdgeInsetsInsetRect(relativeFrame, self.touchAreaEdgeInsets)

        return hitFrame.contains(point)
    }
}

To use it, you can:

button.touchAreaEdgeInsets = UIEdgeInsets(top: -10, left: -10, bottom: -10, right: -10)

I recommend placing a UIButton with type Custom centered over your info button. Resize the custom button to the size you want the hit area to be. From there you have two options:

1. Check the 'Show touch on highlight' option of the custom button. The white glow will appear over the info button, but in most cases the users finger will cover this and all they will see is the glow around the outside.

2. Set up an IBOutlet for the info button and two IBActions for the custom button one for 'Touch Down' and one for the 'Touch Up Inside'. Then in Xcode make the touchdown event set the highlighted property of the info button to YES and the touchupinside event set the highlighted property to NO.