注：文章中部分代码参考了这里,感谢原作者。
AttributedString可以分为NSAttributedString和NSMutableAttributedString两种。在使用中通过将AttributedString赋值给控件的 attributedText 属性来添加文字样式。有属性的控件有UILabel、UITextField和UITextView。
使用方式一
初始化一个NSMutableAttributedString，然后向里面添加文字样式，将其赋给控件的attributedText属性。（这种方式只是简单的用几个属性表示了用法，在下面的一种使用方式中，会详细总结所有属性）
NSString *str = @"人生若只如初见，何事悲风秋画扇。\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。";
//创建NSMutableAttributedString
NSMutableAttributedString *attrStr = [[NSMutableAttributedString alloc]initWithString:str];
//设置字体和设置字体的范围
[attrStr addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:30.0f] range:NSMakeRange(0, 3)];
//添加文字颜色
[attrStr addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(17, 7)];
//添加文字背景颜色
[attrStr addAttribute:NSBackgroundColorAttributeName value:[UIColor orangeColor] range:NSMakeRange(17, 7)];
//添加下划线
[attrStr addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:NSMakeRange(8, 7)];
UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(60, 100, 200, 0)];
label.backgroundColor = [UIColor greenColor];
//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];
使用方式二
创建属性字典，并将各种属性初始化。赋值，并利用方法appendAttributedString:添加入NSMutableAttributedString，将其赋给控件的attributedText属性。
注释感觉写的挺详细，就直接贴代码了：
//初始化NSMutableAttributedString
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc]init];
//设置字体格式和大小
NSString *str0 = @"设置字体格式和大小";
NSDictionary *dictAttr0 = @{NSFontAttributeName:[UIFont systemFontOfSize:14]};
NSAttributedString *attr0 = [[NSAttributedString alloc]initWithString:str0 attributes:dictAttr0];
[attributedString appendAttributedString:attr0];
//设置字体颜色
NSString *str1 = @"\n设置字体颜色\n";
NSDictionary *dictAttr1 = @{NSForegroundColorAttributeName:[UIColor purpleColor]};
NSAttributedString *attr1 = [[NSAttributedString alloc]initWithString:str1 attributes:dictAttr1];
[attributedString appendAttributedString:attr1];
//设置字体背景颜色
NSString *str2 = @"设置字体背景颜色\n";
NSDictionary *dictAttr2 = @{NSBackgroundColorAttributeName:[UIColor cyanColor]};
NSAttributedString *attr2 = [[NSAttributedString alloc]initWithString:str2 attributes:dictAttr2];
[attributedString appendAttributedString:attr2];
/*
注：NSLigatureAttributeName设置连体属性，取值为NSNumber对象（整数），1表示使用默认的连体字符，0表示不使用，2表示使用所有连体符号（iOS不支持2）。而且并非所有的字符之间都有组合符合。如 fly ，f和l会连起来。
*/
//设置连体属性
NSString *str3 = @"fly";
NSDictionary *dictAttr3 = @{NSFontAttributeName:[UIFont fontWithName:@"futura" size:14],NSLigatureAttributeName:[NSNumber numberWithInteger:1]};
NSAttributedString *attr3 = [[NSAttributedString alloc]initWithString:str3 attributes:dictAttr3];
[attributedString appendAttributedString:attr3];
/*!
注：NSKernAttributeName用来设置字符之间的间距，取值为NSNumber对象（整数），负值间距变窄，正值间距变宽
*/
NSString *str4 = @"\n设置字符间距";
NSDictionary *dictAttr4 = @{NSKernAttributeName:@(4)};
NSAttributedString *attr4 = [[NSAttributedString alloc]initWithString:str4 attributes:dictAttr4];
[attributedString appendAttributedString:attr4];
/*!
注：NSStrikethroughStyleAttributeName设置删除线，取值为NSNumber对象，枚举NSUnderlineStyle中的值。NSStrikethroughColorAttributeName设置删除线的颜色。并可以将Style和Pattern相互 取与 获取不同的效果
*/
NSString *str51 = @"\n设置删除线为细单实线,颜色为红色";
NSDictionary *dictAttr51 = @{NSStrikethroughStyleAttributeName:@(NSUnderlineStyleSingle),NSStrikethroughColorAttributeName:[UIColor redColor]};
NSAttributedString *attr51 = [[NSAttributedString alloc]initWithString:str51 attributes:dictAttr51];
[attributedString appendAttributedString:attr51];
NSString *str52 = @"\n设置删除线为粗单实线,颜色为红色";
NSDictionary *dictAttr52 = @{NSStrikethroughStyleAttributeName:@(NSUnderlineStyleThick),NSStrikethroughColorAttributeName:[UIColor redColor]};
NSAttributedString *attr52 = [[NSAttributedString alloc]initWithString:str52 attributes:dictAttr52];
[attributedString appendAttributedString:attr52];
NSString *str53 = @"\n设置删除线为细单实线,颜色为红色";
NSDictionary *dictAttr53 = @{NSStrikethroughStyleAttributeName:@(NSUnderlineStyleDouble),NSStrikethroughColorAttributeName:[UIColor redColor]};
NSAttributedString *attr53 = [[NSAttributedString alloc]initWithString:str53 attributes:dictAttr53];
[attributedString appendAttributedString:attr53];
NSString *str54 = @"\n设置删除线为细单虚线,颜色为红色";
NSDictionary *dictAttr54 = @{NSStrikethroughStyleAttributeName:@(NSUnderlineStyleSingle|NSUnderlinePatternDot),NSStrikethroughColorAttributeName:[UIColor redColor]};
NSAttributedString *attr54 = [[NSAttributedString alloc]initWithString:str54 attributes:dictAttr54];
[attributedString appendAttributedString:attr54];
/*!
NSStrokeWidthAttributeName 设置笔画的宽度，取值为NSNumber对象（整数），负值填充效果，正值是中空效果。NSStrokeColorAttributeName 设置填充部分颜色，取值为UIColor对象。
设置中间部分颜色可以使用 NSForegroundColorAttributeName 属性来进行
*/
//设置笔画宽度和填充部分颜色
NSString *str6 = @"设置笔画宽度和填充颜色\n";
NSDictionary *dictAttr6 = @{NSStrokeWidthAttributeName:@(2),NSStrokeColorAttributeName:[UIColor blueColor]};
NSAttributedString *attr6 = [[NSAttributedString alloc]initWithString:str6 attributes:dictAttr6];
[attributedString appendAttributedString:attr6];
//设置阴影属性，取值为NSShadow对象
NSString *str7 = @"设置阴影属性\n";
NSShadow *shadow = [[NSShadow alloc]init];
shadow.shadowColor = [UIColor redColor];
shadow.shadowBlurRadius = 1.0f;
shadow.shadowOffset = CGSizeMake(1, 1);
NSDictionary *dictAttr7 = @{NSShadowAttributeName:shadow};
NSAttributedString *attr7 = [[NSAttributedString alloc]initWithString:str7 attributes:dictAttr7];
[attributedString appendAttributedString:attr7];
//设置文本特殊效果，取值为NSString类型，目前只有一个可用效果 NSTextEffectLetterpressStyle（凸版印刷效果）
NSString *str8 = @"设置特殊效果\n";
NSDictionary *dictAttr8 = @{NSTextEffectAttributeName:NSTextEffectLetterpressStyle};
NSAttributedString *attr8 = [[NSAttributedString alloc]initWithString:str8 attributes:dictAttr8];
[attributedString appendAttributedString:attr8];
//设置文本附件，取值为NSTextAttachment对象，常用于文字的图文混排
NSString *str9 = @"文字的图文混排\n";
NSTextAttachment *textAttachment = [[NSTextAttachment alloc]init];
textAttachment.image = [UIImage imageNamed:@"logo.png"];
textAttachment.bounds = CGRectMake(0, 0, 30, 30);
NSDictionary *dictAttr9 = @{NSAttachmentAttributeName:textAttachment};
NSAttributedString *attr9 = [[NSAttributedString alloc]initWithString:str9 attributes:dictAttr9];
[attributedString appendAttributedString:attr9];
/*!
添加下划线 NSUnderlineStyleAttributeName。设置下划线的颜色 NSUnderlineColorAttributeName，对象为 UIColor。使用方式同删除线一样。
*/
//添加下划线
NSString *str10 = @"添加下划线\n";
NSDictionary *dictAttr10 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleSingle),NSUnderlineColorAttributeName:[UIColor redColor]};
NSAttributedString *attr10 = [[NSAttributedString alloc]initWithString:str10 attributes:dictAttr10];
[attributedString appendAttributedString:attr10];
/*!
NSBaselineOffsetAttributeName 设置基线偏移值。取值为NSNumber （float），正值上偏，负值下偏
*/
//设置基线偏移值 NSBaselineOffsetAttributeName
NSString *str11 = @"添加基线偏移值\n";
NSDictionary *dictAttr11 = @{NSBaselineOffsetAttributeName:@(-10)};
NSAttributedString *attr11 = [[NSAttributedString alloc]initWithString:str11 attributes:dictAttr11];
[attributedString appendAttributedString:attr11];
/*!
NSObliquenessAttributeName 设置字体倾斜度，取值为 NSNumber（float），正值右倾，负值左倾
*/
//设置字体倾斜度 NSObliquenessAttributeName
NSString *str12 = @"设置字体倾斜度\n";
NSDictionary *dictAttr12 = @{NSObliquenessAttributeName:@(0.5)};
NSAttributedString *attr12 = [[NSAttributedString alloc]initWithString:str12 attributes:dictAttr12];
[attributedString appendAttributedString:attr12];
/*!
NSExpansionAttributeName 设置字体的横向拉伸，取值为NSNumber （float），正值拉伸 ，负值压缩
*/
//设置字体的横向拉伸 NSExpansionAttributeName
NSString *str13 = @"设置字体横向拉伸\n";
NSDictionary *dictAttr13 = @{NSExpansionAttributeName:@(0.5)};
NSAttributedString *attr13 = [[NSAttributedString alloc]initWithString:str13 attributes:dictAttr13];
[attributedString appendAttributedString:attr13];
/*!
NSWritingDirectionAttributeName 设置文字的书写方向，取值为以下组合
@[@(NSWritingDirectionLeftToRight | NSWritingDirectionEmbedding)]
@[@(NSWritingDirectionLeftToRight | NSWritingDirectionOverride)]
@[@(NSWritingDirectionRightToLeft | NSWritingDirectionEmbedding)]
@[@(NSWritingDirectionRightToLeft | NSWritingDirectionOverride)]
???NSWritingDirectionEmbedding和NSWritingDirectionOverride有什么不同
*/
//设置文字的书写方向 NSWritingDirectionAttributeName
NSString *str14 = @"设置文字书写方向\n";
NSDictionary *dictAttr14 = @{NSWritingDirectionAttributeName:@[@(NSWritingDirectionRightToLeft | NSWritingDirectionEmbedding)]};
NSAttributedString *attr14 = [[NSAttributedString alloc]initWithString:str14 attributes:dictAttr14];
[attributedString appendAttributedString:attr14];
/*!
NSVerticalGlyphFormAttributeName 设置文字排版方向，取值为NSNumber对象（整数），0表示横排文本，1表示竖排文本 在iOS中只支持0
*/
//设置文字排版方向 NSVerticalGlyphFormAttributeName
NSString *str15 = @"设置文字排版方向\n";
NSDictionary *dictAttr15 = @{NSVerticalGlyphFormAttributeName:@(0)};
NSAttributedString *attr15 = [[NSAttributedString alloc]initWithString:str15 attributes:dictAttr15];
[attributedString appendAttributedString:attr15];
//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;
//添加段落设置
[attributedString addAttribute:NSParagraphStyleAttributeName value:paragraph range:NSMakeRange(0, attributedString.length)];
UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(60, 100, 300, 0)];
label.backgroundColor = [UIColor lightGrayColor];
//自动换行
label.numberOfLines = 0;
//设置label的富文本
label.attributedText = attributedString;
//label高度自适应
[label sizeToFit];
[self.view addSubview:label];
例子中只是将单个的属性进行展示，可以将不同的属性进行组合来产生所需的效果
需要注意的两个属性：
-
NSTextAttachment实现图文混排 富文本AttributedString之简单实现图文混排(二) -
NSLinkAttributeName实现设置链接属性，点击后调用浏览器打开指定的URL地址，参考富文本AttributedString总结（三）之链接属性的设置
