iOS： 富文本AttributedString的详解

AttributedString可以分为NSAttributedString和NSMutableAttributedString两种，在使用中通过把AttributedString赋值给控件的attributedText属性来添加文字样式。具有该属性的控件有UILabel、UITextField和UITextView。

首先，初始化：

NSString *string = @"这是一个富文本字符串";
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:string];

然后，根据API中属性顺序依次详细说明：

No.1 字体

[attributedString addAttribute:NSFontAttributeName
                         value:[UIFont systemFontOfSize:30.0f]
                         range:NSMakeRange(4, 3)];

No.2 段落

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
//行间距
paragraphStyle.lineSpacing = 5.f;
//段落间距
paragraphStyle.paragraphSpacing = 5.f;
//段落缩进像素
paragraphStyle.firstLineHeadIndent = 25.f;
//整体缩进像素
paragraphStyle.headIndent = 10.f;
//对齐方式
paragraphStyle.alignment = NSTextAlignmentLeft;
//段落[其他属性参照NSMutableParagraphStyle]
[attributedString addAttribute:NSParagraphStyleAttributeName
                         value:paragraphStyle
                         range:NSMakeRange(0, attributedString.length)];

No.3 前景色

[attributedString addAttribute:NSForegroundColorAttributeName
                         value:[[UIColor redColor]
                         range:NSMakeRange(4, 3)];

No.4 背景色

[attributedString addAttribute:NSBackgroundColorAttributeName
                         value:[UIColor redColor]
                         range:NSMakeRange(4, 3)];

No.5 连字符

string = @"flash player";
attributedString = [[NSMutableAttributedString alloc] initWithString:string];
[attributedString addAttribute:NSLigatureAttributeName
                         value:@1
                         range:NSMakeRange(0, 5)];
[attributedString addAttribute:NSFontAttributeName
                         value:[UIFont fontWithName:@"futura" size:30]
                         range:NSMakeRange(0, 5)];

No.6 文字间距

[attributedString addAttribute:NSKernAttributeName
                         value:@10                  
                         range:NSMakeRange(3, 4)];

No.7 删除线

[attributedString addAttribute:NSStrikethroughStyleAttributeName
                         value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle)
                         range:NSMakeRange(4, 3)];
[attributedString addAttribute:NSBaselineOffsetAttributeName
                         value:@1
                         range:NSMakeRange(4, 3)];
[attributedString addAttribute:NSStrikethroughColorAttributeName
                         value:[UIColor redColor]
                         range:NSMakeRange(4, 3)];

No.8 下划线

//下划线
[attributedString addAttribute:NSUnderlineStyleAttributeName
                         value:@(NSUnderlineStyleSingle)
                         range:NSMakeRange(4, 3)];
//下划线颜色
[attributedString addAttribute:NSUnderlineColorAttributeName
                         value:[UIColor redColor]
                         range:NSMakeRange(4, 3)];

No.9 空心字

//描边颜色需和描边宽度一起使用
[attributedString addAttribute:NSStrokeColorAttributeName
                         value:[UIColor redColor]
                         range:NSMakeRange(4, 3)];
[attributedString addAttribute:NSStrokeWidthAttributeName
                         value:@1.5
                         range:NSMakeRange(4, 3)];                  

No.10 阴影

NSShadow *shadow = [[NSShadow alloc] init];  
shadow.shadowOffset = CGSizeMake(0, 1);  
shadow.shadowBlurRadius = 2; 
shadow.shadowColor = [UIColor greenColor];   
[attributedString addAttribute:NSShadowAttributeName
                         value:shadow
                         range:NSMakeRange(4, 3)];    

No.11 图文混排

NSTextAttachment *textAttachment = [[NSTextAttachment alloc] init];
textAttachment.image = [UIImage imageNamed:@"emotion_0"];
textAttachment.bounds = CGRectMake(0, -6, 30, 30);  
NSAttributedString *attachmentAttrStr = [NSAttributedString attributedStringWithAttachment:textAttachment];
[attributedString insertAttributedString:attachmentAttrStr atIndex:7];

No.12 链接

attributedString = [[NSMutableAttributedString alloc] initWithString:@"这是一个网址：https://github.com/dexianyinjiu"];
[attributedString addAttribute:NSLinkAttributeName
                         value:@"https://github.com/dexianyinjiu"
                         range:NSMakeRange(7, attributedString.length-7)];

No.13 基线偏移

[attributedString addAttribute:NSBaselineOffsetAttributeName
                         value:@(10.f)
                         range:NSMakeRange(4, 3)];

No.14 倾斜

[attributedString addAttribute:NSObliquenessAttributeName
                         value:@(0.5f)
                         range:NSMakeRange(4, 3)];

No.15 拉伸/压缩

[attributedString addAttribute:NSExpansionAttributeName
                         value:@(0.5f)
                         range:NSMakeRange(4, 3)];

No.16 书写方向

[attributedString addAttribute:NSWritingDirectionAttributeName
                         value:@[@(NSWritingDirectionRightToLeft | NSWritingDirectionOverride)]
                         range:NSMakeRange(0, attributedString.length)];

No.17 横/竖向排版

//0：横向排版 其他：竖向排版  
[attributedString addAttribute:NSVerticalGlyphFormAttributeName
                         value:@1   
                         range:NSMakeRange(0, attributedString.length)];