NSString *text = @"守夜人誓言：「长夜将至，我从今开始守望，至死方休。我将不娶妻、不封地、不生子。我将不戴宝冠，不争荣宠。我将尽忠职守，生死於斯。我是黑暗中的利剑，长城上的守卫。我是抵御寒冷的烈焰，破晓时分的光线，唤醒眠者的号角，守护王国的坚盾。我将生命与荣耀献给守夜人，今夜如此，夜夜皆然。」";
    //设置文本属性
    NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc]init];
    //设置行间距
    [paraStyle setLineSpacing:5];
    [paraStyle setLineBreakMode:NSLineBreakByWordWrapping];
    //字体大小
    UIFont *textFont = [UIFont systemFontOfSize:15];
    //字体颜色
    UIColor *textColor = [UIColor lightGrayColor];
    NSDictionary *textDic = @{NSFontAttributeName : textFont,NSForegroundColorAttributeName : textColor,NSParagraphStyleAttributeName : paraStyle};
    //富文本
    NSAttributedString *attrText = [[NSAttributedString alloc]initWithString:text attributes:textDic];
    //计算文本的size
    CGSize textSize = [text boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width *0.5, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:textDic context:nil].size;
    
    UILabel *textLabel = [[UILabel alloc]init];
    textLabel.attributedText = attrText;
    textLabel.numberOfLines = 0;
    [self.view addSubview:textLabel];
    //布局
    [textLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.center.mas_equalTo(self.view);
        make.width.mas_equalTo(ceil(textSize.width));//
        make.height.mas_equalTo(ceil(textSize.height));
    }];
    
    //设置虚线边框
    CAShapeLayer *borderLayer = [CAShapeLayer layer];
    borderLayer.bounds = CGRectMake(0, 0, textSize.width + 10, textSize.height + 10);
    //中心点位置
    borderLayer.position = CGPointMake(textSize.width *0.5, textSize.height *0.5);
    
    borderLayer.path = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, textSize.width + 10, textSize.height + 10)].CGPath;
    //边框的宽度
    borderLayer.lineWidth = 3;
    //边框虚线线段的宽度
    borderLayer.lineDashPattern = @[@5,@5];
    borderLayer.fillColor = [UIColor clearColor].CGColor;
    borderLayer.strokeColor = [UIColor purpleColor].CGColor;
    [textLabel.layer addSublayer:borderLayer];

效果图

![Uploading Snip20160513_1_356370.png . . .]

Snip20160513_1.png