NSString *str = @"人生若只如初见，何事秋风悲画扇。\n等闲变却故人心，却道故人心易变。\n骊山语罢清宵半，泪雨霖铃终不怨。\n何如薄幸锦衣郎，比翼连枝当日愿。";
NSMutableAttributedString *attrStr = [[NSMutableAttributedString alloc] initWithString:str];

attrStr添加字体和设置字体的范围

[attrStr addAttribute:NSFontAttributeName
                value:[UIFont systemFontOfSize:30.0f]
                range:NSMakeRange(0, 3)];

attrStr添加文字颜色

[attrStr addAttribute:NSForegroundColorAttributeName
                value:[UIColor redColor]
                range:NSMakeRange(17, 7)];

attrStr添加下划线

[attrStr addAttribute:NSUnderlineStyleAttributeName
                value:[NSNumber numberWithInteger:NSUnderlineStyleSingle]
                range:NSMakeRange(8, 7)];

段落样式

NSMutableParagraphStyle *paragraph = [[NSMutableParagraphStyle alloc] init];
//行间距
paragraph.lineSpacing = 10;
//段落间距
paragraph.paragraphSpacing = 20;
//对齐方式
paragraph.alignment = NSTextAlignmentLeft;
//指定段落开始的缩进像素
paragraph.firstLineHeadIndent = 30;
//调整全部文字的缩进像素
paragraph.headIndent = 10;

attrStr添加段落设置

[attrStr addAttribute:NSParagraphStyleAttributeName
                value:paragraph
                range:NSMakeRange(0, [str length])];

NSString *urlStr = @"www.南瓜瓜.com";
NSURL *url = [NSURL URLWithString:urlStr];

label添加链接
注意：label链接是可以显示出来，但是点不了，有兴趣的朋友可以试试。查资料发现textView是可以点击的，有shouldInteractWithURL代理方法回调。

[attrStr addAttribute:NSLinkAttributeName
                value:url
                range:NSMakeRange(42, 7)];

创建label

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(60, 100, 200, 0)];
label.backgroundColor = [UIColor lightGrayColor];
//自动换行
label.numberOfLines = 0;
//设置label的富文本
label.attributedText = attrStr;
//label高度自适应
[label sizeToFit];
[self.view addSubview:label];

设置sizeToFit之后是可以取出label的高度的，这样做label高度自适应。

CGFloat height = label.frame.size.height;
NSLog(@"height = %f",height);