判断是否点击了某个图层

/** Hit testing methods. **/

/* Returns the farthest descendant of the layer containing point 'p'.
 * Siblings are searched in top-to-bottom order. 'p' is defined to be
 * in the coordinate space of the receiver's nearest ancestor that
 * isn't a CATransformLayer (transform layers don't have a 2D
 * coordinate space in which the point could be specified). */

- (nullable __kindof CALayer *)hitTest:(CGPoint)p;

/* Returns true if the bounds of the layer contains point 'p'. */

- (BOOL)containsPoint:(CGPoint)p;

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    CGPoint touchPoint = [[touches anyObject] locationInView:self.view];
    CALayer *layer = [self.view.layer hitTest:touchPoint];
    
    //点击了图层（有可能为nil）
    NSLog(@"%@",layer);
}

屏幕快照 2019-04-24 下午11.34.43.png
屏幕快照 2019-04-24 下午11.35.28.png