//設置圖片
self.DottedLine.image = [self imageWithLineWithImageView:self.DottedLine];

//畫虛線方法
-(UIImage *)imageWithLineWithImageView:(UIImageView *)imageView{
    CGFloat width = imageView.frame.size.width;
    CGFloat height = imageView.frame.size.height;
    UIGraphicsBeginImageContext(imageView.frame.size);
    [imageView.image drawInRect:CGRectMake(0, 0, width, height)];
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
    CGFloat lengths[] = {5,5};//虛線的長度設置
    CGContextRef line = UIGraphicsGetCurrentContext();
    CGContextSetStrokeColorWithColor(line, [UIColor colorWithRed:133/255.0 green:133/255.0 blue:133/255.0 alpha:1.0].CGColor);
//畫線
    CGContextSetLineDash(line, 0, lengths, 1);
    CGContextMoveToPoint(line, 0, 1);
    CGContextAddLineToPoint(line, width-5, 1);
    CGContextStrokePath(line);
    return  UIGraphicsGetImageFromCurrentImageContext();
}

效果圖

68B0C875-4E58-43E0-99E6-530CA9D16220.png

Alert:
只是測試了這一種方法,還有其他的方法,回頭測試了再貼出來