动画后禁用UIButton

Question

我有这个按钮并应用这个动画。 问题是在动画之后，按钮似乎被禁用。 该按钮位于UIView中，但其位置是固定的，不明白为什么它被禁用。

CABasicAnimation *alphaAnimation;

alphaAnimation=[CABasicAnimation animationWithKeyPath:@"opacity"];
alphaAnimation.duration=0.5;
alphaAnimation.repeatCount=1;
alphaAnimation.autoreverses=NO;
alphaAnimation.fromValue=[NSNumber numberWithFloat:0.0];
alphaAnimation.toValue=[NSNumber numberWithFloat:1.0];

CAKeyframeAnimation *pulseAnimation;
pulseAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform.scale"];
pulseAnimation.duration = 0.5;
pulseAnimation.repeatCount = 1;
pulseAnimation.values = [NSArray arrayWithObjects:
                         [NSNumber numberWithFloat:0.5],
                         [NSNumber numberWithFloat:1.2],
                         [NSNumber numberWithFloat:1.0], nil];
pulseAnimation.keyTimes = [NSArray arrayWithObjects:
                           [NSNumber numberWithFloat:0],
                           [NSNumber numberWithFloat:0.5],
                           [NSNumber numberWithFloat:1.0], nil];

pulseAnimation.timingFunctions = [NSArray arrayWithObjects:
                                  [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn],        // from keyframe 1 to keyframe 2
                                  [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut], nil]; // from keyframe 2 to keyframe 3

pulseAnimation.removedOnCompletion = NO;
pulseAnimation.fillMode = kCAFillModeForwards;

CAAnimationGroup *nearbyAnimation = [CAAnimationGroup animation];
[nearbyAnimation setAnimations:[NSArray arrayWithObjects:pulseAnimation, alphaAnimation, nil]];
[nearbyAnimation setDuration:0.5];
[nearbyAnimation setBeginTime:0.0];
[nearbyAnimation setRemovedOnCompletion:NO];
[nearbyAnimation setFillMode:kCAFillModeForwards];
[nearbyButton.layer addAnimation:nearbyAnimation forKey:nil];

由于