iOS CoreAnimation教程 第五篇

CoreAnimation 虚线的设置 。ineDashPattern ，虚线设置，为一个数组，数组中奇数位实线长度，偶数位带遍空白长度。注意最好是偶数否则你看着这个效果不规则。

  CAShapeLayer * oval = [CAShapeLayer layer];
    oval.frame           = CGRectMake(187.3, 88.5, 151, 151);
    oval.lineJoin        = kCALineJoinRound;
    oval.fillColor       = [UIColor colorWithRed:0.922 green: 0.922 blue:0.922 alpha:1].CGColor;
    oval.strokeColor     = [UIColor colorWithRed:0.329 green: 0.329 blue:0.329 alpha:1].CGColor;
    oval.lineWidth       = 9;
    oval.lineDashPattern = @[@10, @5];
    oval.lineDashPhase   = 57.5;
    oval.path            = [self ovalPath].CGPath;

lineDashPhase 虚线开始的位置，当你这个值逐渐递增时候你会看到一个滚动效果，且大于0.