NSAttributeString使用介紹（含經常使用Attribute鍵值對照表）

###1、Attributes字典鍵值對照表

鍵	值類型	備註
NSKernAttributeName	NSNumber	文字間距，支持浮點型
NSFontAttributeName	UIFont	字體
NSForegroundColorAttributeName	UIColor	顏色
NSParagraphStyleAttributeName	NSMutableParagraphStyle	段落樣式，詳細見【1】
NSBackgroundColorAttributeName	UIColor	字體的所佔區域的背景顏色
NSStrokeColorAttributeName	UIColor	字體邊框的顏色
NSStrokeWidthAttribute	NSNumber	邊框的寬度
NSStrikethroughStyleAttributeName	NSNumber	刪除線
NSUnderlineStyleAttributeName	NSNumber	下劃線
NSVerticalGlyphFormAttributeName	NSNumber	文字排版方向0 表示橫排文本.1 表示豎排文本，iOS只有橫排
NSObliquenessAttributeName	NSNumber	文字傾斜程度
NSExpansionAttributeName	NSNumber	文字的扁平化程度
NSShadowAttributeName	NSShadow	文字陰影，見【2】

【1】NSMutableParagraphStyle類使用範例

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineSpacing = 10;// 字體的行間距
paragraphStyle.firstLineHeadIndent = 20.0f;//首行縮進
paragraphStyle.alignment = NSTextAlignmentJustified;//（兩端對齊的）文本對齊方式：（左，中，右，兩端對齊，天然）
paragraphStyle.lineBreakMode = NSLineBreakByTruncatingTail;//結尾部分的內容以……方式省略 ( "...wxyz" ,"abcd..." ,"ab...yz")
paragraphStyle.headIndent = 20;//總體縮進(首行除外)
paragraphStyle.tailIndent = 20;//尾部縮進
paragraphStyle.minimumLineHeight = 10;//最低行高
paragraphStyle.maximumLineHeight = 20;//最大行高
paragraphStyle.paragraphSpacing = 15;//段與段之間的間距
paragraphStyle.paragraphSpacingBefore = 22.0f;//段首行空白空間/* Distance between the bottom of the previous paragraph (or the end of its paragraphSpacing, if any) and the top of this paragraph. */paragraphStyle.baseWritingDirection = NSWritingDirectionLeftToRight;//從左到右的書寫方向（一共➡️⬇️⬅️三種）
paragraphStyle.lineHeightMultiple = 15;/* Natural line height is multiplied by this factor (if positive) before being constrained by minimum and maximum line height. */
paragraphStyle.hyphenationFactor = 1;//連字屬性 在iOS，惟一支持的值分別爲0和1
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【2】NSShadowAttributeName對應的是NSShadow對象,單一使用不會有任何效果,須要配合着NSVerticalGlyphFormAttributeName(文字排版方向)、NSObliquenessAttributeName(文字傾斜)、NSExpansionAttributeName(文字扁平化)配合使用,NSShadow相關屬性設置以下所示.

NSShadow *shadow = [[NSShadow alloc]init];
shadow.shadowBlurRadius = 5;//模糊度
shadow.shadowColor = [UIColor whiteColor];//陰影顏色
shadow.shadowOffset = CGSizeMake(1, 5);//陰影的大小
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2、 NSAttributedString與NSMutableAttributedString

1.NSAttributedString 屬性

//均爲只讀
@property (readonly, copy) NSString *string;
@property (readonly) NSUInteger length;
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建立方法

- (instancetype)initWithString:(NSString *)str;
- (instancetype)initWithAttributedString:(NSAttributedString *)attrStr;
- (instancetype)initWithString:(NSString *)str attributes:(nullable NSDictionary<NSString *, id> *)attrs;
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其餘方法

//富文本字符串比較
- (BOOL)isEqualToAttributedString:(NSAttributedString *)other;
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2.NSMutableAttributedString 做爲NSAttributedString的子類增長了如下動態添加富文本樣式的方法，見文思意，也沒必要過多解釋。

- (void)addAttribute:(NSString *)name value:(id)value range:(NSRange)range;
- (void)addAttributes:(NSDictionary<NSString *, id> *)attrs range:(NSRange)range;
- (void)removeAttribute:(NSString *)name range:(NSRange)range;
- (void)replaceCharactersInRange:(NSRange)range withAttributedString:(NSAttributedString *)attrString;
- (void)insertAttributedString:(NSAttributedString *)attrString atIndex:(NSUInteger)loc;
- (void)appendAttributedString:(NSAttributedString *)attrString;

//徹底替換掉attributeString的內容
- (void)setAttributedString:(NSAttributedString *)attrString;
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我是分割區~~~大神，女友喊你回家吃飯，你能夠先走了。

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###3、demo 若是以上看完了，還不懂怎麼使用的朋友。那不妨看看在下拙劣的demo吧。(注：Label的背景顏色都是在xib（nib）中設置的)

• 文字間距

  

NSAttributedString *string = [[NSAttributedString alloc] initWithString:@"改變文字間距,間距爲6"attributes:@{NSKernAttributeName:@6}];
    _label1.attributedText = string;
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• 字體

NSAttributedString *string = [[NSAttributedString alloc] initWithString:@"改變文字字體,20號粗體"attributes:@{NSFontAttributeName:[UIFont boldSystemFontOfSize:20]}];
    _label2.attributedText = string;
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• 顏色

NSAttributedString *string = [[NSAttributedString alloc] initWithString:@"改變文字顏色,綠色"attributes:@{NSForegroundColorAttributeName:[UIColor greenColor]}];
    _label3.attributedText = string;
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• 描邊和空心

NSMutableAttributedString *mutableAttributedstring = [[NSMutableAttributedString alloc] initWithString:@"改變文字邊框顏色寬度,這二者協同使用纔有效果，寬度正數爲空心（前景色失效），負數描邊"];
    //空心
    [mutableAttributedstring addAttribute:NSStrokeWidthAttributeName value:@3.2 range:NSMakeRange(0, 37)];
    [mutableAttributedstring addAttribute:NSStrokeColorAttributeName value:[UIColor greenColor] range:NSMakeRange(0, 37)];
    
    //描邊
    [mutableAttributedstring addAttribute:NSStrokeWidthAttributeName value:@-5 range:NSMakeRange(38, mutableAttributedstring.length - 38)];
    [mutableAttributedstring addAttribute:NSStrokeColorAttributeName value:[UIColor redColor] range:NSMakeRange(38, mutableAttributedstring.length - 38)];
    _label4.numberOfLines = 3;
    _label4.attributedText = mutableAttributedstring;

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• 刪除線

NSMutableAttributedString *mutableAttributedstring = [[NSMutableAttributedString alloc] initWithString:@"一條刪除線，兩條刪除線，加粗刪除線"];
    [mutableAttributedstring addAttribute:NSStrikethroughStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:NSMakeRange(0,5)];
    [mutableAttributedstring addAttribute:NSStrikethroughStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleDouble] range:NSMakeRange(6,5)];
    [mutableAttributedstring addAttribute:NSStrikethroughStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleThick] range:NSMakeRange(12,5)];
    _label5.attributedText = mutableAttributedstring;
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• 下劃線

NSMutableAttributedString *mutableAttributedstring = [[NSMutableAttributedString alloc] initWithString:@"一條下劃線，兩條下劃線，加粗下劃線"];
    [mutableAttributedstring addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:NSMakeRange(0,5)];
    [mutableAttributedstring addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleDouble] range:NSMakeRange(6,5)];
    [mutableAttributedstring addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleThick] range:NSMakeRange(12,5)];
    _label6.attributedText = mutableAttributedstring;
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• 斜體、陰影和壓扁

NSMutableAttributedString *mutableAttributedstring = [[NSMutableAttributedString alloc] initWithString:@"文字傾斜，文字陰影，壓扁文字"];
    [mutableAttributedstring addAttribute:NSObliquenessAttributeName value:@1 range:NSMakeRange(0,4)];
    
    //文字陰影
    NSShadow *shadow = [[NSShadow alloc] init];
    //模糊度
    shadow.shadowBlurRadius = 5;
    //陰影顏色
    shadow.shadowColor = [UIColor yellowColor];
    //陰影大小
    shadow.shadowOffset = CGSizeMake(2, 5);
    [mutableAttributedstring addAttribute:NSShadowAttributeName value:shadow range:NSMakeRange(5,4)];
    
    //壓扁文字
    [mutableAttributedstring addAttribute:NSExpansionAttributeName value:@0.8 range:NSMakeRange(10,4)];
    _label7.numberOfLines = 2;
     _label7.attributedText = mutableAttributedstring;
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• 段落樣式

NSMutableAttributedString *mutableAttributedstring = [[NSMutableAttributedString alloc] initWithString:@"據外媒報道，美國太空探索技術公司SpaceX原定於北京時間2月18日23時01分，在佛羅里達州發射「龍」無人貨運飛船，運送補給物資前往國際太空站，並嘗試回收搭載飛船的「獵鷹9」號火箭。但二級火箭在倒計時13秒時因引擎故障，宣佈取消發射。\n在發射暫停後約10分鐘後，SpaceX首席執行官埃隆·馬斯克(Elon Musk)在社交媒體上發佈消息稱：「一切運行正常，除了二級火箭發動機轉向液壓活塞的運動軌跡稍顯奇怪，須要進行調查。」"];
    
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    // 字體的行間距
    paragraphStyle.lineSpacing = 10;
    //首行縮進
    paragraphStyle.firstLineHeadIndent = 20.0f;
    //（兩端對齊的）文本對齊方式：（左，中，右，兩端對齊，天然）
//    paragraphStyle.alignment = NSTextAlignmentLeft;
    //結尾部分的內容以……方式省略 ( "...wxyz" ,"abcd..." ,"ab...yz")
//    paragraphStyle.lineBreakMode = NSLineBreakByTruncatingTail;
    paragraphStyle.headIndent = 20;//總體縮進(首行除外)
    //設置尾部縮進後就出問題
//    paragraphStyle.tailIndent = 2;//尾部縮進
    paragraphStyle.minimumLineHeight = 10;//最低行高
    paragraphStyle.maximumLineHeight = 20;//最大行高
//    paragraphStyle.paragraphSpacing = 15;//段與段之間的間距
    paragraphStyle.paragraphSpacingBefore = 22.0f;//段首行空白空間/* Distance between the bottom of the previous paragraph (or the end of its paragraphSpacing, if any) and the top of this paragraph. */
    paragraphStyle.baseWritingDirection = NSWritingDirectionLeftToRight;//從左到右的書寫方向（一共➡️⬇️⬅️三種）
    
    paragraphStyle.lineHeightMultiple = 15;/* Natural line height is multiplied by this factor (if positive) before being constrained by minimum and maximum line height. */
    paragraphStyle.hyphenationFactor = 1;//連字屬性 在iOS，惟一支持的值分別爲0和1
    [mutableAttributedstring addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, mutableAttributedstring.length)];
    [mutableAttributedstring addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:10] range:NSMakeRange(0, mutableAttributedstring.length)];
    _label8.numberOfLines = MAXFLOAT;
    _label8.attributedText = mutableAttributedstring;
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經常使用的也就這些了吧，更深刻仍是用富文本框架吧。