一、重寫drawRect方法

    - (void)drawRect:(CGRect)rect
    {
     [super drawRect:rect];
    CGContextRef currentContext = UIGraphicsGetCurrentContext();
    //設置虛線顏色
     CGContextSetStrokeColorWithColor(currentContext, [UIColor     BlackColor].CGColor);
     //設置虛線寬度
     CGContextSetLineWidth(currentContext, 1);
     //設置虛線繪制起點
     CGContextMoveToPoint(currentContext, 0, 0);
     //設置虛線繪制終點
     CGContextAddLineToPoint(currentContext, self.frame.origin.x + self.frame.size.width, 0);
     //設置虛線排列的寬度間隔:下面的arr中的數字表示先繪制3個點再繪制1個點
     CGFloat arr[] = {3,1};
     //下面最后一個參數“2”代表排列的個數。
     CGContextSetLineDash(currentContext, 0, arr, 2);
     CGContextDrawPath(currentContext, kCGPathStroke);
    }

二、采用CAShapeLayer方式繪制虛線

    CAShapeLayer *shapeLayer = [CAShapeLayer layer];
    [shapeLayer setBounds:self.bounds];
    [shapeLayer setPosition:CGPointMake(self.frame.size.width / 2.0,       self.frame.size.height)];
    [shapeLayer setFillColor:[UIColor clearColor].CGColor];
    //設置虛線顏色
    shapeLayer setStrokeColor:[UIColor BlackColor].CGColor];
    //設置虛線寬度
    [shapeLayer setLineWidth:self.frame.size.height];
    [shapeLayer setLineJoin:kCALineJoinRound];
    //設置虛線的線寬及間距
     [shapeLayer setLineDashPattern:[NSArray arrayWithObjects:[NSNumber       numberWithInt:3], [NSNumber numberWithInt:1], nil]];
     //創建虛線繪制路徑
     CGMutablePathRef path = CGPathCreateMutable();
     //設置虛線繪制路徑起點
     CGPathMoveToPoint(path, NULL, 0, 0);
     //設置虛線繪制路徑終點
      CGPathAddLineToPoint(path, NULL, self.frame.size.width, 0);
       //設置虛線繪制路徑
     [shapeLayer setPath:path];
     CGPathRelease(path);
     //添加虛線
     [self.layer addSublayer:shapeLayer];

三、經濟實惠型：采用貼圖的方式繪制虛線（需要設計師切圖配合）

      UIImageView *imgDashLineView =[[UIImageView alloc] initWithFrame:CGRectMake(15, 200, self.view.frame.size.width - 30, 1)];
    [imgDashLineView setBackgroundColor:[UIColor colorWithPatternImage:[UIImage         imageNamed:@"xuxian.png"]]];
      [self.view addSubview:imgDashLineView];