iOS繪製虛線方法

/**
 ** lineView:      需要繪製成虛線的view
 ** lineLength:    虛線的寬度 //2
 ** lineSpacing:        虛線的間距//1
 ** lineColor:    虛線的顏色
 **/
+ (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];
  //  設置虛線顏色爲blackColor
  [shapeLayer setStrokeColor:lineColor.CGColor];
  //  設置虛線寬度
  [shapeLayer setLineWidth:CGRectGetHeight(lineView.frame)];
  [shapeLayer setLineJoin:kCALineJoinRound];
  //  設置線寬，線間距
  [shapeLayer setLineDashPattern:[NSArray arrayWithObjects:[NSNumber numberWithInt:lineLength], [NSNumber numberWithInt:lineSpacing], nil]];
  //  設置路徑
  CGMutablePathRef path = CGPathCreateMutable();
  CGPathMoveToPoint(path, NULL, 0, 0);
  CGPathAddLineToPoint(path, NULL, CGRectGetWidth(lineView.frame), 0);
  [shapeLayer setPath:path];
  CGPathRelease(path);
  //  把繪製好的虛線添加上來
  [lineView.layer addSublayer:shapeLayer];
}

效果如下：