基于CAReplicatorLayer创建动画

这是2015年3月的新加入的iOS动画，你可能从来没有听说过CAReplicatorLayer，那是一个很酷难以理解但强大的CoreAnimation类。

先上效果图

20行代码创建动画，直接上代码

 /** CAReplicatorLayer可以复制自己子层的layer,并且复制的出来的layer和原来的子layer拥有相同的动效*/
 CAReplicatorLayer *replicatorLayer = [CAReplicatorLayer layer];

replicatorLayer.bounds = CGRectMake(0.0,0.0,100.0,100.0);

replicatorLayer.cornerRadius = 10.0;

 /** 视图相对于父视图的重心位置*/
replicatorLayer.position = self.center;

replicatorLayer.backgroundColor = [UIColor colorWithRed:0.1 green:0.1 blue:0.1 alpha:0.1].CGColor;

 [self.layer addSublayer:replicatorLayer];


 CALayer *dot = [CALayer layer];
 dot.bounds = CGRectMake(0, 0, 10, 10);
 dot.position = CGPointMake(50, 20);
 dot.backgroundColor = [UIColor colorWithRed:0.1 green:0.1 blue:0.1 alpha:0.6].CGColor;
 dot.cornerRadius = 5;
dot.masksToBounds = YES;

[replicatorLayer addSublayer:dot];

 CGFloat count = 10.0;

replicatorLayer.instanceCount = count; //小圆圈的个数

CGFloat nrDots = 2 * M_PI/count;
replicatorLayer.instanceTransform = CATransform3DMakeRotation(nrDots, 0, 0, 1); //每次旋转的角度等于2π/ 10

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
animation.duration = 1; //1秒的延迟动画。在到原来的点上做缩放变化
animation.fromValue = @(1);
animation.toValue = @(0.1);
animation.repeatCount = MAXFLOAT;
[dot addAnimation:animation forKey:nil];

replicatorLayer.instanceDelay = 1.0/count; //使动画动起来的秘诀就是给出一点延迟到每一个副本

dot.transform = CATransform3DMakeScale(0.01, 0.01, 0.01); //解决旋转衔接效果

完整代码demo下载