新建category类目

#import@interface UIButton (EnlargeTouchArea)

- (void)setEnlargeEdgeWithTop:(CGFloat) top right:(CGFloat) right bottom:(CGFloat) bottom left:(CGFloat) left;

- (void)setEnlargeEdge:(CGFloat) size;

@end

#import "UIButton+EnlargeTouchArea.h"

#import@implementation UIButton (EnlargeTouchArea)

static char topNameKey;

static char rightNameKey;

static char bottomNameKey;

static char leftNameKey;

- (void)setEnlargeEdge:(CGFloat) size

{

    objc_setAssociatedObject(self, &topNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &rightNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &bottomNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &leftNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);

}

- (void) setEnlargeEdgeWithTop:(CGFloat) top right:(CGFloat) right bottom:(CGFloat) bottom left:(CGFloat) left

{

    objc_setAssociatedObject(self, &topNameKey, [NSNumber numberWithFloat:top], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &rightNameKey, [NSNumber numberWithFloat:right], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &bottomNameKey, [NSNumber numberWithFloat:bottom], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &leftNameKey, [NSNumber numberWithFloat:left], OBJC_ASSOCIATION_COPY_NONATOMIC);

}

- (CGRect) enlargedRect

{

    NSNumber* topEdge = objc_getAssociatedObject(self, &topNameKey);

    NSNumber* rightEdge = objc_getAssociatedObject(self, &rightNameKey);

    NSNumber* bottomEdge = objc_getAssociatedObject(self, &bottomNameKey);

    NSNumber* leftEdge = objc_getAssociatedObject(self, &leftNameKey);

    if (topEdge && rightEdge && bottomEdge && leftEdge)

    {

        return CGRectMake(self.bounds.origin.x - leftEdge.floatValue,

                          self.bounds.origin.y - topEdge.floatValue,

                          self.bounds.size.width + leftEdge.floatValue + rightEdge.floatValue,

                          self.bounds.size.height + topEdge.floatValue + bottomEdge.floatValue);

    }

    else

    {

        return self.bounds;

    }

}

- (UIView*) hitTest:(CGPoint) point withEvent:(UIEvent*) event

{

    CGRect rect = [self enlargedRect];

    if (CGRectEqualToRect(rect, self.bounds))

    {

        return [super hitTest:point withEvent:event];

    }

    return CGRectContainsPoint(rect, point) ? self : nil;

}

@end

使用方法，下载链接

1.[button setEnlargeEdge:20];

2.[button setEnlargeEdgeWithTop:10 right:10 bottom:10 left:10];