如何同步几个不同图层的 CAKeyframeAnimation 动画？

Question

我需要为 5 个视图的移动设置动画，每个视图都从前一个视图延迟开始。我已经有了一个视图的工作动画：

// Create position points
NSArray * pathArray = @[
                        [NSValue valueWithCGPoint:CGPointMake(0, 0)],
                        [NSValue valueWithCGPoint:CGPointMake(50, 0)],
                        [NSValue valueWithCGPoint:CGPointMake(80, 0)],
                        [NSValue valueWithCGPoint:CGPointMake(130, 0)]
                        ];

// Create animation 
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];

pathAnimation.values = pathArray;

// Add relative timing for each position
pathAnimation.keyTimes = [NSArray arrayWithObjects:
                      [NSNumber numberWithFloat:0],
                      [NSNumber numberWithFloat:.2],
                      [NSNumber numberWithFloat:.8],
                      [NSNumber numberWithFloat:1.0], nil];

// Define animation type for each frame
pathAnimation.timingFunctions = [NSArray arrayWithObjects:
                             [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn], // from keyframe 1 to keyframe 2
                             [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear], // from keyframe 2 to keyframe 3
                             [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn], nil]; // from keyframe 3 to keyframe 4

// Set duration for whole animation
pathAnimation.duration = 1.0;

// Perform repeat
pathAnimation.repeatCount = HUGE_VALF;

// Add animation
CALayer *layer = _myView.layer;
[layer addAnimation:pathAnimation forKey:@"position"];

现在我需要以某种方式使用 4 个具有相同动画但有延迟的视图，以便所有 5 个视图都按顺序进行动画处理。例如，我需要在 1 秒后为第二个视图设置动画，然后在 1 秒后为第三个视图设置动画，以此类推。应该如何正确完成？

Answer 1

您应该使用CACurrentMediaTime()。我也有类似的问题，看看这个answer

Answer 2

“按顺序制作动画……”嗯，这听起来像 CAAnimationGroup。

https://developer.apple.com/library/ios/documentation/graphicsimaging/reference/CAAnimationGroup_class/Introduction/Introduction.html

CAAnimationGroup 要求您执行显式图层动画，而不是视图动画。但是您正在制作显式图层动画，所以一切就绪。