子view超出父view范围无法响应

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    UIView *result = [super hitTest:point withEvent:event];
    CGPoint buttonPoint = [self.button convertPoint:point fromView:self];
    if ([self.button pointInside:buttonPoint withEvent:event]) {
        return self.button;
    }
    return result;
}