iOS技术文档No.10 AppKit_NSAttributedString、NSMutableAttributedString iOS富文本

在iOS开发中，常常会有一段文字显示不同的颜色和字体，或者给某几个文字加删除线或下划线的需求。这些都可以用强大的NSMuttableAttstring实现。

1.加载HTML标签文本

因为解析的数据里面有html标签，就使用下面的代码把字符串转换成data，初始化时再用HTML类型，转换为富文本。

 NSMutableAttributedString * attrStr = [[NSMutableAttributedString alloc] 
initWithData:[str dataUsingEncoding:NSUnicodeStringEncoding] options:@{ 
NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType } documentAttributes:nil 
error:nil];

参数options里面的字典有三对key value
文档类型NSDocumentTypeDocumentAttribute

 NSPlainTextDocumentType  // 普通文本
 NSRTFTextDocumentType   //  富文本
 NSRTFDTextDocumentType   // 带附件的富文本
 NSHTMLTextDocumentType  // 这个可以加载HTML格式的文本

编码格式NSCharacterEncodingDocumentAttribute

[NSNumber numberWithInt:NSUTF8StringEncoding]; // 不再一一列举

默认NSDefaultAttributesDocumentAttribute
这个不知道对应的value是什么

2.富文本总结

这是富文本的所有属性

| 属性Name | 作用 | 类型 |
| :---: | :----: | :-------: | :----: |
| NSFontAttributeName | 字号 |UIFont 默认12|
| NSParagraphStyleAttributeName |段落样式 | NSParagraphStyle |
| NSForegroundColorAttributeName | 前景色 | UIColor |
| NSBackgroundColorAttributeName | 背景色 | UIColor |
| NSObliquenessAttributeName | 字体倾斜 | NSNumber |
| NSExpansionAttributeName | 字体加粗 |NSNumber 比例 0就是不变 1增加一倍|
| NSKernAttributeName | 字间距 | CGFloat |
| NSUnderlineStyleAttributeName | 下划线 |1或0|
| NSUnderlineColorAttributeName | 下划线颜色 | UIColor |
| NSStrikethroughStyleAttributeName | 删除线 |1或0|
| NSStrikethroughColorAttributeName | 删除线颜色 | UIColor |
| NSStrokeColorAttributeName | same as ForegroundColor | UIColor |
| NSStrokeWidthAttributeName | 字体描边 | CGFloat |
| NSLigatureAttributeName | 连笔字 没看出效果 |1或0|
| NSShadowAttributeName |阴影| NSShawdow |
| NSTextEffectAttributeName |设置文本特殊效果,目前只有图版印刷效果可用| NSString |
| NSAttachmentAttributeName |设置文本附件,常用插入图片| NSTextAttachment |
| NSLinkAttributeName |链接| NSURL (preferred) or NSString |
| NSBaselineOffsetAttributeName |基准线偏移| NSNumber |
| NSWritingDirectionAttributeName |文字方向 分别代表不同的文字出现方向等等，我想你一定用不到它 - -|@[@(1),@(2)]|
| NSVerticalGlyphFormAttributeName |水平或者竖直文本 在iOS没卵用，不支持竖版|1竖直 0水平|

解释一下其中的三个类型

段落样式

段落样式主要改行距、段距、首行缩进、最大最小行高、多倍行距等十几个属性，把这些总结了你就比我更全..

NSMutableParagraphStyle *muParagraph = [[NSMutableParagraphStyle alloc]init];
    muParagraph.lineSpacing = 10; // 行距
    muParagraph.paragraphSpacing = 20; // 段距
    muParagraph.firstLineHeadIndent = 30; // 首行缩进

阴影

就三属性，不用解释了

NSShadow *shadow = [[NSShadow alloc]init];
    shadow.shadowOffset = CGSizeMake(2, 2);
    shadow.shadowColor = [UIColor orangeColor];
    shadow.shadowBlurRadius = 1;

附件，图片

参考iOS技术文档No.7 UIKit_NSTextAttachment为富文本添加图片
NSTextAttachment *attachment=[[NSTextAttachment alloc] initWithData:nil ofType:nil];
UIImage *img=[UIImage imageNamed:@"test.png"];
attachment.image=img;
attachment.bounds=CGRectMake(0, 0, 20, 20);
NSAttributedString *text = [NSAttributedString attributedStringWithAttachment:attachment];
如果你想要添加自定义view也请参考我的另一篇文章iOS技术文档No.7 UIKit_NSTextAttachment为富文本添加图片

3.属性及方法

/*
    NSAttributedString
*/
@property (readonly, copy) NSString *string; // 无属性的字符串
@property (readonly) NSUInteger length; // 字符串长度
 
// 初始化方法
- (instancetype)initWithString:(NSString *)str;
- (instancetype)initWithString:(NSString *)str attributes:(nullable NSDictionary *)attrs;
- (instancetype)initWithAttributedString:(NSAttributedString *)attrStr;
// 等同性判断
- (BOOL)isEqualToAttributedString:(NSAttributedString *)other;
// 返回指定范围的属性
- (NSDictionary *)attributesAtIndex:(NSUInteger)location longestEffectiveRange:(nullable NSRangePointer)range inRange:(NSRange)rangeLimit;
- (nullable id)attribute:(NSString *)attrName atIndex:(NSUInteger)location longestEffectiveRange:(nullable NSRangePointer)range inRange:(NSRange)rangeLimit;
// 遍历获得符合指定属性或属性字典的区域(range)，并在 block 中进行设置
- (void)enumerateAttributesInRange:(NSRange)enumerationRange options:(NSAttributedStringEnumerationOptions)opts usingBlock:(void (^)(NSDictionary *attrs, NSRange range, BOOL *stop))block;
- (void)enumerateAttribute:(NSString *)attrName inRange:(NSRange)enumerationRange options:(NSAttributedStringEnumerationOptions)opts usingBlock:(void (^)(id __nullable value, NSRange range, BOOL *stop))block;
 
/*
    NSMutableAttributedString
*/
// 增加属性
- (void)addAttribute:(NSString *)name value:(id)value range:(NSRange)range;
- (void)addAttributes:(NSDictionary *)attrs range:(NSRange)range;
- (void)setAttributedString:(NSAttributedString *)attrString;
- (void)setAttributes:(nullable NSDictionary *)attrs range:(NSRange)range;
// 删除属性
- (void)removeAttribute:(NSString *)name range:(NSRange)range;
// 插入 attributedString
- (void)insertAttributedString:(NSAttributedString *)attrString atIndex:(NSUInteger)loc;
- (void)appendAttributedString:(NSAttributedString *)attrString;
// 替换 attributedString
- (void)replaceCharactersInRange:(NSRange)range withString:(NSString *)str;
- (void)replaceCharactersInRange:(NSRange)range withAttributedString:(NSAttributedString *)attrString;

代码

self.attTV=[[UITextView alloc]initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)];
    self.attTV.backgroundColor=[UIColor whiteColor];
    [self.view addSubview:self.attTV];
    
    //NSFontAttributeName   字号 UIFont 默认12
    //NSParagraphStyleAttributeName    段落样式  NSParagraphStyle
    //NSForegroundColorAttributeName    前景色   UIColor
    //NSBackgroundColorAttributeName    背景色   UIColor
    //NSObliquenessAttributeName        字体倾斜     NSNumber
    //NSExpansionAttributeName          字体加粗     NSNumber  比例 0就是不变 1增加一倍
    //NSKernAttributeName               字间距   CGFloat
    //NSUnderlineStyleAttributeName     下划线     1或0
    //NSUnderlineColorAttributeName     下划线颜色
    //NSStrikethroughStyleAttributeName 删除线   1或0
    //NSStrikethroughColorAttributeName 某种颜色
    //NSStrokeColorAttributeName        same as ForegroundColor
    //NSStrokeWidthAttributeName        CGFloat
    //NSLigatureAttributeName           连笔字  1或0  没看出效果
    //NSShadowAttributeName             阴影    NSShawdow
    //NSTextEffectAttributeName          设置文本特殊效果，取值为 NSString 对象，目前只有图版印刷效果可用：
    //NSAttachmentAttributeName         NSTextAttachment  设置文本附件,常用插入图片
    //NSLinkAttributeName               链接  NSURL (preferred) or NSString
    //NSBaselineOffsetAttributeName     基准线偏移   NSNumber
    
    //NSWritingDirectionAttributeName   文字方向     @[@(1),@(2)]  分别代表不同的文字出现方向等等，我想你一定用不到它 - -
    //NSVerticalGlyphFormAttributeName  水平或者竖直文本  1竖直 0水平 在iOS没卵用，不支持竖版
    
    NSParagraphStyle *paragraph = [[NSParagraphStyle alloc]init];
    NSMutableParagraphStyle *muParagraph = [[NSMutableParagraphStyle alloc]init];
    muParagraph.lineSpacing = 10; // 行距
    muParagraph.paragraphSpacing = 20; // 段距
    muParagraph.firstLineHeadIndent = 30; // 首行缩进
    
    
    NSMutableAttributedString * attrStr = [[NSMutableAttributedString alloc] initWithData:[@"我嫉妒你的爱气势如虹，像个人气高居不下的天后，你要的不是我而是一种虚荣，有人疼才显得多么出众" dataUsingEncoding:NSUnicodeStringEncoding] options:@{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType } documentAttributes:nil error:nil];
    
    
    NSRange range = NSMakeRange(0, attrStr.length);
    // 设置字体大小
    [attrStr addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:20] range:range];
    //字间距
    [attrStr addAttribute:NSKernAttributeName value:@(2) range:range];
    // 字体倾斜
    [attrStr addAttribute:NSObliquenessAttributeName value:@(1) range:range];
    // 字体加粗
    [attrStr addAttribute:NSExpansionAttributeName value:@(0.5) range:range];
    // 下划线
    [attrStr addAttribute:NSUnderlineStyleAttributeName value:@(1) range:range];
    [attrStr addAttribute:NSUnderlineColorAttributeName value:[UIColor blueColor] range:range];
    // 删除线
    [attrStr addAttribute:NSStrikethroughStyleAttributeName value:@(1) range:range];
    [attrStr addAttribute:NSStrikethroughColorAttributeName value:[UIColor greenColor] range:range];
    
    // 连体字
    [attrStr addAttribute:NSLigatureAttributeName value:@(1) range:range];
    
    
    // 设置颜色
    [attrStr addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:0.942 green:0.611 blue:0.771 alpha:1.000] range:range];
    // 背景色
    [attrStr addAttribute:NSBackgroundColorAttributeName value:[UIColor colorWithRed:0.475 green:0.482 blue:0.942 alpha:1.000] range:range];
    
    // stroke
    [attrStr addAttribute:NSStrokeColorAttributeName value:[UIColor blueColor] range:range];
    [attrStr addAttribute:NSStrokeWidthAttributeName value:@(2) range:range];
    
    // 设置段落样式
    [attrStr addAttribute:NSParagraphStyleAttributeName value:muParagraph range:range];
    
    // 文本方向
    [attrStr addAttribute:NSVerticalGlyphFormAttributeName value:@(1) range:range];
    [attrStr addAttribute:NSWritingDirectionAttributeName value:@[@(2),@(3)] range:range];
    
    
    // 阴影
    NSShadow *shadow = [[NSShadow alloc]init];
    shadow.shadowOffset = CGSizeMake(2, 2);
    shadow.shadowColor = [UIColor orangeColor];
    shadow.shadowBlurRadius = 1;
    [attrStr addAttribute:NSShadowAttributeName value:shadow range:range];
    
    // 链接
    [attrStr addAttribute:NSLinkAttributeName value:[NSURL URLWithString:@"http://www.jianshu.com/p/8f49c9c99b21"] range:range];
    
    // 文字中加图片
    NSTextAttachment *attachment=[[NSTextAttachment alloc] initWithData:nil ofType:nil];
    
    UIImage *img=[UIImage imageNamed:@"1"];
    attachment.image=img;
    attachment.bounds=CGRectMake(0, 0, 30, 30);
    NSAttributedString *image = [NSAttributedString attributedStringWithAttachment:attachment];
//    [attrStr addAttribute:NSAttachmentAttributeName value:attachment range:range];
    [attrStr appendAttributedString:image];
    
    // 基准线偏移
    [attrStr addAttribute:NSBaselineOffsetAttributeName value:@(50) range:range];
    
    self.attTV.attributedText = attrStr;