iOS method containsPoint is not working - ios

Question

I have a view like this:
// .h file
#interface LayerBubbleView : UIView
/**
* click handler
*/
#property (nonatomic, copy) void (^clickHandler)(NSString* identifier, CAShapeLayer* layer);
-(instancetype)initWithFrame:(CGRect)frame withDataArray:(NSArray *)dataArray;
#end
// .m file
#import "BDPLayerBubbleView.h"
#interface BDPLayerBubbleView ()
#property (nonatomic, strong) NSMutableArray *paths;
#property (nonatomic, strong) NSMutableArray *identifiers;
#end
#implementation BDPLayerBubbleView
-(instancetype)initWithFrame:(CGRect)frame withDataArray:(NSArray *)dataArray {
self = [self initWithFrame:frame];
if (self) {
_paths = [[NSMutableArray alloc] init];
_identifiers = [[NSMutableArray alloc] init];
for (int i = 0; i < dataArray.count; i++) {
NSArray *data = dataArray[i];
CGRect frame = [data[0] CGRectValue]; // please ignore here, just for demo
CGFloat radius = [data[1] doubleValue];
CGPoint center = [data[2] CGPointValue];
UIColor *fillColor = data[3];
UIColor *borderColor = data[4];
NSString *identifier = data[5];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
UIBezierPath *bezierPath = [UIBezierPath bezierPathWithRoundedRect:frame cornerRadius:radius];
[_paths addObject:bezierPath];
[_identifiers addObject:identifier];
shapeLayer.path = [bezierPath CGPath];
shapeLayer.strokeColor = [borderColor CGColor];
shapeLayer.fillColor = [fillColor CGColor];
shapeLayer.lineWidth = 0.5;
shapeLayer.bounds = frame;
shapeLayer.position = center;
[self.layer addSublayer:shapeLayer];
}
}
return self;
}
#pragma mark - Touch handling
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint touchPoint = [touch locationInView:self];
for(int i=0;i<[_paths count];i++) {
UIBezierPath* path = _paths[i];
CAShapeLayer *shapeLayer = self.layer.sublayers[i];
if ([path containsPoint:touchPoint] || [shapeLayer containsPoint:touchPoint])
{
NSString *identifier = _identifiers[i];
if([self.layer.sublayers[i] isKindOfClass:CAShapeLayer.class] && [identifier length] > 0) {
CAShapeLayer* l = self.layer.sublayers[i];
if(_clickHandler) {
_clickHandler(identifier, l);
}
}
}
}
}
The logic is, there are lots of bubble layers on the view, and when user taps on the bubble, I can detect which bubble layer user taps, so I can trigger the corresponding clickHandler and highlight the bubble layer.
However, neither [path containsPoint:touchPoint] nor [shapeLayer containsPoint:touchPoint] return YES for all the sub layers. I am not sure what's wrong with my code?
So I was suggest to use CGPathContainsPoint and CGRectContainsPoint to detect. I tested, CGPathContainsPoint DOES NOT work while CGRectContainsPointDID work.
I am now confused the differences among the CG APIs and the UIKit wrapped APIs. Could any expert to explain? I still hope containsPoint can work.