设置layer的path为NSBezierPath对象，再对layer添加animation，注意
[CABasicAnimation animationWithKeyPath:@"strokeEnd"] 中的keyPath不能随意更改。
CAShapeLayer *l = [CAShapeLayer layer]; l.frame = self.view.bounds; l.strokeColor = [UIColor redColor].CGColor; CGPoint start = CGPointMake(arc4random()%300+10, arc4random()%400+40); CGPoint end = CGPointMake(arc4random()%300+10, arc4random()%400+40); UIBezierPath *path = [[UIBezierPath alloc] init]; [path moveToPoint:start]; [path addLineToPoint:end]; l.path = path.CGPath; [path release]; CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"]; animation.fromValue = [NSNumber numberWithFloat:0.0f]; animation.toValue = [NSNumber numberWithFloat:1.0f]; animation.duration = 3.0f; [l addAnimation:animation forKey:@"myStroke"]; [self.view.layer addSublayer:l];
check：http://stackoverflow.com/questions/7966590/iphone-core-animation-animate-a-nsbezierpath
也可以参考一份代码：https://github.com/ole/Animated-Paths 其实现的效果在code4app中有介绍http://code4app.com/ios/Animated-Paths/5020854c6803faa152000000
本文转自老Zhan博客园博客，原文链接：http://www.cnblogs.com/mybkn/archive/2012/08/21/2648708.html，如需转载请自行联系原作者
