为什么这个 CAKeyFrameAnimation 会以零不透明度停止？

我有这个代码。在值数组的末尾，您可以看到我提供了 0.5 的不透明度。但由于某种原因，当动画停止时，它会再次闪烁，然后使视图完全透明。那里出了什么问题？

CALayer *layer = self.layer;
CAKeyframeAnimation *blinkAnim = [CAKeyframeAnimation animationWithKeyPath:@"opacity"];
blinkAnim.duration = 1.0;
//blinkAnim.repeatCount = 0;
blinkAnim.autoreverses = NO;

// keyframe times and values
// we want to start fully opaque, fade out, stay faded out and fade back in shortly before the end of the cycle
blinkAnim.keyTimes = [NSArray arrayWithObjects: [NSNumber numberWithFloat:0.0],
                      [NSNumber numberWithFloat:0.4],
                      [NSNumber numberWithFloat:0.6],
                      [NSNumber numberWithFloat:0.85],
                      [NSNumber numberWithFloat:1.0], nil];
blinkAnim.values = [NSArray arrayWithObjects:   [NSNumber numberWithFloat:1.0],
                    [NSNumber numberWithFloat:1.0],
                    [NSNumber numberWithFloat:0.0],
                    [NSNumber numberWithFloat:0.0],
                    [NSNumber numberWithFloat:0.5], nil];
[layer addAnimation:blinkAnim forKey:nil];

默认fillMode (see here http://developer.apple.com/documentation/graphicsimaging/Reference/CAMediaTiming_protocol/Introduction/Introduction.html#//apple_ref/doc/constant_group/Fill_Modes) for a CAAnimation is kCAFillModeRemoved。您应该设置fillMode你的动画到kCAFillModeForwards，并且还设置removedOnCompletion财产给NO（默认情况下是YES):

blinkAnim.removedOnCompletion = NO;
blinkAnim.fillMode = kCAFillModeForwards;

您会注意到这些属性是在我为您之前的问题编写的源代码中设置的——它们在那里是有原因的。