方法一：
#import
@interface UIButton (EnlargeTouchArea)
- (void)setEnlargeEdgeWithTop:(CGFloat) top right:(CGFloat) right bottom:(CGFloat) bottom left:(CGFloat) left;
@end
#import "UIButton+EnlargeTouchArea.h"
#import
@implementation UIButton (EnlargeTouchArea)
static char topNameKey;
static char rightNameKey;
static char bottomNameKey;
static char leftNameKey;
- (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;
}
方法二：
Apple的iOS人機交互設計指南中指出，按鈕點擊熱區應不小于44x44pt，否則這個按鈕就會讓用戶覺得“很難用”，因為明明點擊上去了，卻沒有任何響應。
但我們有時做自定義Button的時候，設計圖上的給出按鈕尺寸明顯要小于這個數。例如我之前做過的自定義Slider上的Thumb只有12x12pt，做出來后我發現自己根本點不到按鈕……
這個問題在WWDC 2012 Session 216視頻中提到了一種解決方式。它重寫了按鈕中的pointInside方法，使得按鈕熱區不夠44×44大小的先自動縮放到44×44，再判斷觸摸點是否在新的熱區內。
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent*)event
{
CGRect bounds = self.bounds;
//若原熱區小于44x44，則放大熱區，否則保持原大小不變
CGFloat widthDelta = MAX(44.0 - bounds.size.width, 0);
CGFloat heightDelta = MAX(44.0 - bounds.size.height, 0);
bounds = CGRectInset(bounds, -0.5 * widthDelta, -0.5 * heightDelta);
return CGRectContainsPoint(bounds, point);
}
