IOS 绘制虚线方法

/**
 ** lineView:      需要绘制成虚线的view
 ** lineLength:  虚线的宽度
 ** lineSpacing:    虚线的间距
 ** lineColor:    虚线的颜色
 **/
+ (void)drawDashLine:(UIView *)lineView lineLength:(int)lineLength lineSpacing:(int)lineSpacing lineColor:(UIColor *)lineColor
{
  CAShapeLayer *shapeLayer = [CAShapeLayer layer];
  [shapeLayer setBounds:lineView.bounds];
  [shapeLayer setPosition:CGPointMake(CGRectGetWidth(lineView.frame) / 2, CGRectGetHeight(lineView.frame))];
  [shapeLayer setFillColor:[UIColor clearColor].CGColor];
  //  设置虚线颜色为blackColor
  [shapeLayer setStrokeColor:lineColor.CGColor];
  //  设置虚线宽度
  [shapeLayer setLineWidth:CGRectGetHeight(lineView.frame)];
  [shapeLayer setLineJoin:kCALineJoinRound];
  //  设置线宽，线间距
  [shapeLayer setLineDashPattern:[NSArray arrayWithObjects:[NSNumber numberWithInt:lineLength], [NSNumber numberWithInt:lineSpacing], nil]];
  //  设置路径
  CGMutablePathRef path = CGPathCreateMutable();
  CGPathMoveToPoint(path, NULL, 0, 0);
  CGPathAddLineToPoint(path, NULL, CGRectGetWidth(lineView.frame), 0);
  [shapeLayer setPath:path];
  CGPathRelease(path);
  //  把绘制好的虚线添加上来
  [lineView.layer addSublayer:shapeLayer];
}