iOS NSAttributedString（属性字符串）

NSAttributedString实际上就是一个字符串和一本字典。

字典包含每一个字符的属性：包括字体、大小、下划线、颜色等等。

关键是要知道字典中每个key的含义以及相应value的取值范围

Character Attributes（重点）

NSString *const  NSFontAttributeName ;                   // 设置字体，UIFont对象，默认12-point Helvetica(Neue)NSString *const  NSParagraphStyleAttributeName ;         // （重要）设置段落风格，NSParagraphStyle对象，默认是[NSParagraphStyle defaultParagraphStyle]，这里可以设置很多段落格式，首行缩进之类的NSString *const  NSForegroundColorAttributeName ;        // 字体颜色，UIColor对象，默认黑色NSString *const  NSBackgroundColorAttributeName ;        // 背景色，UIColor对象，默认透明NSString *const  NSLigatureAttributeName ;               // <span style="color:#FF0000;">（********）不知道干嘛用</span>NSString *const  NSKernAttributeName ;                   // 字符间距，NSNumber 浮点数，默认为0NSString *const  NSStrikethroughStyleAttributeName ;     // 删除线的线粗，NSNumber 整数，默认是NSUnderlineStyleNone（你真的没看错）NSString *const  NSUnderlineStyleAttributeName ;         // 下划线的线粗，NSNumber 整数，默认同上，还有别的样式，例如双下划线NSString *const  NSStrokeColorAttributeName ;            // 描边颜色，UIColor对象，默认同字体颜色NSString *const  NSStrokeWidthAttributeName ;            // 描边，NSNumber 浮点数，正值表示镂空描边，负值标志填充描边，值表示描边线粗NSString *const  NSShadowAttributeName ;                 // 阴影，NSShadow对象，效果参照最后的图片NSString *const  NSTextEffectAttributeName ;             // 文本风格，NSSting对象，默认为nil，官方举例NSTextEffectLetterpressStyle，其实也就只有这个风格。。。感觉有跟没有差不多NSString *const  NSAttachmentAttributeName ;             // <span style="color:#FF0000;">（********）文本附件属性</span>， NSTextAttachment对象，其中包含有图片，等我找到典型案例再回来重新介绍NSString *const  NSLinkAttributeName ;                   // 链接某个地址，NSURL(推荐)或NSString对象，默认为nil不指定任何链接。这里有详细介绍，http://blog.csdn.net/reylen/article/details/18958995NSString *const  NSBaselineOffsetAttributeName ;         // 基线偏移量，NSNumber 浮点数，可以上下微调字体的位置。（适合那些返回位置信息不正确的字体）NSString *const  NSUnderlineColorAttributeName ;         // 下划线颜色NSString *const  NSStrikethroughColorAttributeName ;     // 删除线颜色NSString *const  NSObliquenessAttributeName ;            // 斜体，NSNumber 浮点数，默认0，数值表示倾斜度NSString *const  NSExpansionAttributeName ;              // 水平拉伸，NSNumber 浮点数，默认0，水平拉伸字体，高度不变。NSString *const  NSWritingDirectionAttributeName ;       // <span style="color:#FF0000;">（********）</span>书写方向，NSArray NSNumber（而且只能是整数0，1，2，3），没看到什么效果，找到案例再来更新NSString *const  NSVerticalGlyphFormAttributeName;       // 水平或垂直显示，NSNumber（只有0：水平和1：垂直），没看到效果。。。

Text Writing Direction

用于"NSWritingDirectionAttributeName"

typedef enum : NSInteger  {   NSTextWritingDirectionEmbedding      = (0 << 1),   NSTextWritingDirectionOverride       = (1 << 1)} NSTextWritingDirection;

Text Effect Attribute

用于"NSTextEffectAttributeName"

NSString *const  NSTextEffectLetterpressStyle;

Underline and Strikethrough Style Attributes

用于"NSUnderlineStyleAttributeName"和"NSStrikethroughStyleAttributeName"

typedef enum : NSInteger  {   NSUnderlineStyleNone  = 0x00 ,   NSUnderlineStyleSingle  = 0x01 ,   NSUnderlineStyleThick  = 0x02 ,   NSUnderlineStyleDouble  = 0x09 ,   NSUnderlinePatternSolid  = 0x0000 ,   NSUnderlinePatternDot  = 0x0100 ,   NSUnderlinePatternDash  = 0x0200 ,   NSUnderlinePatternDashDot  = 0x0300 ,   NSUnderlinePatternDashDotDot  = 0x0400 ,   NSUnderlineByWord  = 0x8000 } NSUnderlineStyle;

String Drawing Options

enum {   NSStringDrawingTruncatesLastVisibleLine  = 1 << 5,   NSStringDrawingUsesLineFragmentOrigin  = 1 << 0,   NSStringDrawingUsesFontLeading  = 1 << 1,   NSStringDrawingUsesDeviceMetrics  = 1 << 3,};typedef NSInteger  NSStringDrawingOptions;

Document Types

NSString  *NSPlainTextDocumentType;NSString  *NSRTFTextDocumentType;NSString  *NSRTFDTextDocumentType;NSString  *NSHTMLTextDocumentType;

Keys for Options and Document Attributes Dictionaries

NSString *const  NSDocumentTypeDocumentAttribute ;NSString *const  NSCharacterEncodingDocumentAttribute ;NSString *const  NSDefaultAttributesDocumentAttribute ;NSString *const  NSPaperSizeDocumentAttribute ;NSString *const  NSPaperMarginDocumentAttribute ;NSString *const  NSViewSizeDocumentAttribute ;NSString *const  NSViewZoomDocumentAttribute ;NSString *const  NSViewModeDocumentAttribute ;NSString *const  NSReadOnlyDocumentAttribute ;NSString *const  NSBackgroundColorDocumentAttribute ;NSString *const  NSHyphenationFactorDocumentAttribute ;NSString *const  NSDefaultTabIntervalDocumentAttribute ;NSString *const  NSTextLayoutSectionsAttribute;

Text Layout Sections Attribute

NSString  *NSTextLayoutSectionOrientation;NSString  *NSTextLayoutSectionRange;

NSString的属性常量，貌似部分可以用在Character Attributes里面

UILineBreakMode已由NSLineBreakMode代替。Keys for Text Attributes Dictionaries已在ios 7中被抛弃。剩下以下三类常量可以使用。

NSTextAlignment：

enum {   NSTextAlignmentLeft       = 0,   NSTextAlignmentCenter     = 1,   NSTextAlignmentRight      = 2,   NSTextAlignmentJustified  = 3,   // 两端对齐   NSTextAlignmentNatural    = 4,};typedef NSInteger  NSTextAlignment;

UIBaselineAdjustment：

用于"NSBaselineOffsetAttributeName"字符属性

typedef enum {   UIBaselineAdjustmentAlignBaselines ,   // 根据文字的baseLine调整   UIBaselineAdjustmentAlignCenters ,     // 根据框的水平中心线调整   UIBaselineAdjustmentNone ,             // 以左上角为基准，默认对齐方式} UIBaselineAdjustment;

NSWritingDirection：

enum {   NSWritingDirectionNatural  = -1,      // Use the Unicode Bidi algorithm rules P2 and P3 to determine which direction to use.   NSWritingDirectionLeftToRight  =  0,  // 从左到右   NSWritingDirectionRightToLeft  =  1   // 从右到左};

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UITextViewDelegate调用流程：

1.点击TextView内部，出现光标前。

- (BOOL)textViewShouldBeginEditing:(UITextView *)textView;

如果返回NO，则不会进入编辑，不会出现光标，也不会调用textViewDidBeginEditing:方法。

当选定点选字符串中其他位置，还是会调用didChangeSelection方法

2.出现光标后

- (void)textViewDidBeginEditing:(UITextView *)textView;

3.移动光标或选定某些字符串

- (void)textViewDidChangeSelection:(UITextView *)textView;

4.添加、删除一个字符

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;<pre name="code" class="objc">- (void)textViewDidChangeSelection:(UITextView *)textView;

- (void)textViewDidChange:(UITextView *)textView;

如果第1个方法返回NO，不会调用下面两个方法。

5.不知道怎么结束编辑。。。先留着。（***）

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附类定义

UITextView

NS_CLASS_AVAILABLE_IOS(2_0) @interface UITextView : UIScrollView <UITextInput>@property(nonatomic,assign) id<UITextViewDelegate> delegate;    // 代理@property(nonatomic,copy) NSString *text;@property(nonatomic,retain) UIFont *font;@property(nonatomic,retain) UIColor *textColor;@property(nonatomic) NSTextAlignment textAlignment;    // default is NSLeftTextAlignment@property(nonatomic) NSRange selectedRange;@property(nonatomic,getter=isEditable) BOOL editable;@property(nonatomic,getter=isSelectable) BOOL selectable NS_AVAILABLE_IOS(7_0); // toggle selectability, which controls the ability of the user to select content and interact with URLs & attachments@property(nonatomic) UIDataDetectorTypes dataDetectorTypes NS_AVAILABLE_IOS(3_0);@property(nonatomic) BOOL allowsEditingTextAttributes NS_AVAILABLE_IOS(6_0); // defaults to NO@property(nonatomic,copy) NSAttributedString *attributedText NS_AVAILABLE_IOS(6_0); // default is nil@property(nonatomic,copy) NSDictionary *typingAttributes NS_AVAILABLE_IOS(6_0); // automatically resets when the selection changes- (void)scrollRangeToVisible:(NSRange)range;// Presented when object becomes first responder.  If set to nil, reverts to following responder chain.  If// set while first responder, will not take effect until reloadInputViews is called.@property (readwrite, retain) UIView *inputView;             @property (readwrite, retain) UIView *inputAccessoryView;@property(nonatomic) BOOL clearsOnInsertion NS_AVAILABLE_IOS(6_0); // defaults to NO. if YES, the selection UI is hidden, and inserting text will replace the contents of the field. changing the selection will automatically set this to NO.// Create a new text view with the specified text container (can be nil) - this is the new designated initializer for this class- (instancetype)initWithFrame:(CGRect)frame textContainer:(NSTextContainer *)textContainer NS_AVAILABLE_IOS(7_0);// Get the text container for the text view@property(nonatomic,readonly) NSTextContainer *textContainer NS_AVAILABLE_IOS(7_0);// Inset the text container's layout area within the text view's content area@property(nonatomic, assign) UIEdgeInsets textContainerInset NS_AVAILABLE_IOS(7_0);// Convenience accessors (access through the text container)@property(nonatomic,readonly) NSLayoutManager *layoutManager NS_AVAILABLE_IOS(7_0);@property(nonatomic,readonly,retain) NSTextStorage *textStorage NS_AVAILABLE_IOS(7_0);// Style for links@property(nonatomic, copy) NSDictionary *linkTextAttributes NS_AVAILABLE_IOS(7_0);@endUIKIT_EXTERN NSString * const UITextViewTextDidBeginEditingNotification;UIKIT_EXTERN NSString * const UITextViewTextDidChangeNotification;UIKIT_EXTERN NSString * const UITextViewTextDidEndEditingNotification;

NSAttributedString

@interface NSAttributedString : NSObject <NSCopying, NSMutableCopying, NSSecureCoding>@property (readonly, copy) NSString *string;- (NSDictionary *)attributesAtIndex:(NSUInteger)location effectiveRange:(NSRangePointer)range;@end@interface NSAttributedString (NSExtendedAttributedString)@property (readonly) NSUInteger length;- (id)attribute:(NSString *)attrName atIndex:(NSUInteger)location effectiveRange:(NSRangePointer)range;- (NSAttributedString *)attributedSubstringFromRange:(NSRange)range;- (NSDictionary *)attributesAtIndex:(NSUInteger)location longestEffectiveRange:(NSRangePointer)range inRange:(NSRange)rangeLimit;- (id)attribute:(NSString *)attrName atIndex:(NSUInteger)location longestEffectiveRange:(NSRangePointer)range inRange:(NSRange)rangeLimit;- (BOOL)isEqualToAttributedString:(NSAttributedString *)other;- (instancetype)initWithString:(NSString *)str;- (instancetype)initWithString:(NSString *)str attributes:(NSDictionary *)attrs;- (instancetype)initWithAttributedString:(NSAttributedString *)attrStr;typedef NS_OPTIONS(NSUInteger, NSAttributedStringEnumerationOptions) {  NSAttributedStringEnumerationReverse = (1UL << 1),  NSAttributedStringEnumerationLongestEffectiveRangeNotRequired = (1UL << 20)};- (void)enumerateAttributesInRange:(NSRange)enumerationRange options:(NSAttributedStringEnumerationOptions)opts usingBlock:(void (^)(NSDictionary *attrs, NSRange range, BOOL *stop))block NS_AVAILABLE(10_6, 4_0);- (void)enumerateAttribute:(NSString *)attrName inRange:(NSRange)enumerationRange options:(NSAttributedStringEnumerationOptions)opts usingBlock:(void (^)(id value, NSRange range, BOOL *stop))block NS_AVAILABLE(10_6, 4_0);@endNS_CLASS_AVAILABLE(10_0, 3_2)@interface NSMutableAttributedString : NSAttributedString- (void)replaceCharactersInRange:(NSRange)range withString:(NSString *)str;- (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range;@end@interface NSMutableAttributedString (NSExtendedMutableAttributedString)@property (readonly, retain) NSMutableString *mutableString;- (void)addAttribute:(NSString *)name value:(id)value range:(NSRange)range;- (void)addAttributes:(NSDictionary *)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;- (void)deleteCharactersInRange:(NSRange)range;- (void)setAttributedString:(NSAttributedString *)attrString;- (void)beginEditing;- (void)endEditing;@end

代理协议UITextViewDelegate

@protocol UITextViewDelegate <NSObject, UIScrollViewDelegate>@optional- (BOOL)textViewShouldBeginEditing:(UITextView *)textView;- (BOOL)textViewShouldEndEditing:(UITextView *)textView;- (void)textViewDidBeginEditing:(UITextView *)textView;- (void)textViewDidEndEditing:(UITextView *)textView;- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;- (void)textViewDidChange:(UITextView *)textView;- (void)textViewDidChangeSelection:(UITextView *)textView;- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange NS_AVAILABLE_IOS(7_0);- (BOOL)textView:(UITextView *)textView shouldInteractWithTextAttachment:(NSTextAttachment *)textAttachment inRange:(NSRange)characterRange NS_AVAILABLE_IOS(7_0);@end

NSShadow

NS_CLASS_AVAILABLE_IOS(6_0) @interface NSShadow : NSObject <NSCopying, NSCoding>@property (nonatomic, assign) CGSize shadowOffset;      // 影子与字符串的偏移量@property (nonatomic, assign) CGFloat shadowBlurRadius; // 影子的模糊程度@property (nonatomic, retain) id shadowColor;           // 影子的颜色@end

shadow属性的效果

NSShadow *shadow = [[NSShadow alloc]init];    shadow.shadowOffset = CGSizeMake(5, 5);     // 影子偏移量    shadow.shadowColor = [UIColor blueColor];   // 影子颜色    shadow.shadowBlurRadius = 20.0;             // 模糊程度            NSDictionary *dict = @{                           NSFontAttributeName:[UIFont fontWithName:@"Marion-Italic" size:50.0],                           NSShadowAttributeName:shadow,                           NSKernAttributeName:@(2)                           };    textView.attributedText = [[NSAttributedString alloc]initWithString:@"中文究竟是\nEnglishReally" attributes:dict];

功能太强大，一天总结不完。以后用到再上来补充。

如果你有一些iOS文字处理的问题，欢迎评论交流。