iOS事件分发

@interface STPView : UIView
 
@end
 
@implementation STPView
 
- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
        button.frame = CGRectMake(0, 0, CGRectGetWidth(frame), CGRectGetHeight(frame) / 2);
        button.tag = 10001;
        button.backgroundColor = [UIColor grayColor];
        [button setTitle:@"Button1" forState:UIControlStateNormal];
        [self addSubview:button];
        [button addTarget:self action:@selector(_buttonActionFired:) forControlEvents:UIControlEventTouchDown];
        
        UIButton *button2 = [UIButton buttonWithType:UIButtonTypeCustom];
        button2.frame = CGRectMake(0, CGRectGetHeight(frame) / 2, CGRectGetWidth(frame), CGRectGetHeight(frame) / 2);
        button2.tag = 10002;
        button2.backgroundColor = [UIColor darkGrayColor];
        [button2 setTitle:@"Button2" forState:UIControlStateNormal];
        [self addSubview:button2];
        [button2 addTarget:self action:@selector(_buttonActionFired:) forControlEvents:UIControlEventTouchDown];
    }
    return self;
}
 
- (void)_buttonActionFired:(UIButton *)button {
    NSLog(@"=====Button Titled %@ ActionFired ", [button titleForState:UIControlStateNormal]);
}
 
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    UIView *hitView = [super hitTest:point withEvent:event];
    if (hitView == [self viewWithTag:10001]) {
        return [self viewWithTag:10002];
    }
    return hitView;
}
 
@end

/**
 * @abstract hitTestBlock
 *
 * @param 其余参数 参考UIView hitTest:withEvent:
 * @param returnSuper 是否返回Super的值。如果*returnSuper=YES,则代表会返回 super hitTest:withEvent:, 否则则按照block的返回值(即使是nil)
 * 
 * @discussion 切记，千万不要在这个block中调用self hitTest:withPoint,否则则会造成递归调用。这个方法就是hitTest:withEvent的一个代替。
 */
typedef UIView * (^STHitTestViewBlock)(CGPoint point, UIEvent *event, BOOL *returnSuper);
typedef BOOL (^STPointInsideBlock)(CGPoint point, UIEvent *event, BOOL *returnSuper);
 
@interface UIView (STHitTest)
/// althought this is strong ,but i deal it with copy
@property(nonatomic, strong) STHitTestViewBlock hitTestBlock;
@property(nonatomic, strong) STPointInsideBlock pointInsideBlock;
 
@end

@implementation UIView (STHitTest)
 
const static NSString *STHitTestViewBlockKey = @"STHitTestViewBlockKey";
const static NSString *STPointInsideBlockKey = @"STPointInsideBlockKey";
 
+ (void)load {
    method_exchangeImplementations(class_getInstanceMethod(self, @selector(hitTest:withEvent:)),
                                   class_getInstanceMethod(self, @selector(st_hitTest:withEvent:)));
    method_exchangeImplementations(class_getInstanceMethod(self, @selector(pointInside:withEvent:)),
                                   class_getInstanceMethod(self, @selector(st_pointInside:withEvent:)));
}
 
- (UIView *)st_hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    NSMutableString *spaces = [NSMutableString stringWithCapacity:20];
    UIView *superView = self.superview;
    while (superView) {
        [spaces appendString:@"----"];
        superView = superView.superview;
    }
    NSLog(@"%@%@:[hitTest:withEvent:]", spaces, NSStringFromClass(self.class));
    UIView *deliveredView = nil;
    // 如果有hitTestBlock的实现，则调用block
    if (self.hitTestBlock) {
        BOOL returnSuper = NO;
        deliveredView = self.hitTestBlock(point, event, &returnSuper);
        if (returnSuper) {
            deliveredView = [self st_hitTest:point withEvent:event];
        }
    } else {
        deliveredView = [self st_hitTest:point withEvent:event];
    }
//    NSLog(@"%@%@:[hitTest:withEvent:] Result:%@", spaces, NSStringFromClass(self.class), NSStringFromClass(deliveredView.class));
    return deliveredView;
}
 
- (BOOL)st_pointInside:(CGPoint)point withEvent:(UIEvent *)event {
    NSMutableString *spaces = [NSMutableString stringWithCapacity:20];
    UIView *superView = self.superview;
    while (superView) {
        [spaces appendString:@"----"];
        superView = superView.superview;
    }
    NSLog(@"%@%@:[pointInside:withEvent:]", spaces, NSStringFromClass(self.class));
    BOOL pointInside = NO;
    if (self.pointInsideBlock) {
        BOOL returnSuper = NO;
        pointInside =  self.pointInsideBlock(point, event, &returnSuper);
        if (returnSuper) {
            pointInside = [self st_pointInside:point withEvent:event];
        }
    } else {
        pointInside = [self st_pointInside:point withEvent:event];
    }
    return pointInside;
}
 
- (void)setHitTestBlock:(STHitTestViewBlock)hitTestBlock {
    objc_setAssociatedObject(self, (__bridge const void *)(STHitTestViewBlockKey), hitTestBlock, OBJC_ASSOCIATION_COPY);
}
 
- (STHitTestViewBlock)hitTestBlock {
    return objc_getAssociatedObject(self, (__bridge const void *)(STHitTestViewBlockKey));
}
 
- (void)setPointInsideBlock:(STPointInsideBlock)pointInsideBlock {
    objc_setAssociatedObject(self, (__bridge const void *)(STPointInsideBlockKey), pointInsideBlock, OBJC_ASSOCIATION_COPY);
}
 
- (STPointInsideBlock)pointInsideBlock {
    return objc_getAssociatedObject(self, (__bridge const void *)(STPointInsideBlockKey));
}
 
@end

STPWindow:[hitTest:withEvent:]
----UIView:[hitTest:withEvent:]
--------STPView:[hitTest:withEvent:]
--------UICollectionView:[hitTest:withEvent:]
------------UIImageView:[hitTest:withEvent:]
------------UIImageView:[hitTest:withEvent:]
------------STDefaultRefreshControl:[hitTest:withEvent:]
------------STPFeedCell:[hitTest:withEvent:]
------------STPFeedCell:[hitTest:withEvent:]
----------------UIView:[hitTest:withEvent:]
--------------------UIImageView:[hitTest:withEvent:]
------------------------UIImageView:[hitTest:withEvent:]
------------------------UIView:[hitTest:withEvent:]
------------------------STImageView:[hitTest:withEvent:]