TextKit入門? 表情鍵盤? 圖文混排? --看我就夠了

weixin_33936401發表於2016-09-17

前言

現在市場上大部分資訊展示類應用都有用到圖文混排,我之前對這塊也是一知半解,最近放假正好深入瞭解一下這塊,在這裡對此做一個總結,廢話不多說,先上 demo 地址
TextKit入門 demo地址
精仿手工課 demo地址
精仿手工課部落格地址

背景知識

在正式開始學習之前,我們先來了解一下圖文混排在 iOS 上面的發展,拋棄 coretext (涉及到一些底層,這裡不討論)不說,蘋果在 iOS6給出了*** NSMutableAttributedString這個類,簡單的說就是帶屬性的字串,用它可以實現圖文混排,在 iOS7蘋果則給出了更加強大的 API--textKit,用 textKit***可以實現更加複雜的介面,接下來讓我們開始浪起來吧

694552-57efc1ca2aca4ae6.gif
1.gif

富文字(NSMutableAttributedString)

NSMutableAttributedString和陣列一樣分為可變字串和不可變字串, NSAttributedString就是不可變字串
NSMutableAttributedString簡單的說就是一個帶屬性的字串,因此它的使用非常簡單,

  • 1.初始化字串
  • 2.初始化字串所需要的屬性
  • 3.將屬性賦值給字串
    初始化方法
    - (instancetype)initWithString:(NSString *)str;
    - (instancetype)initWithString:(NSString *)str attributes:(nullable NSDictionary<NSString *, id> *)attrs;
    - (instancetype)initWithAttributedString:(NSAttributedString *)attrStr;
    初始化屬性
  • NSFontAttributeName 字型
  • NSForegroundColorAttributeName 字型顏色
  • NSBackgroundColorAttributeName 背景顏色
  • NSLigatureAttributeName 連字元
    該屬性所對應的值是一個 NSNumber 物件(整數)。連體字元是指某些連在一起的字元,它們採用單個的圖元符號。
    0 表示沒有連體字元。
    1 表示使用預設的連體字元。
    2 表示使用所有連體符號。預設值為 1(注意,iOS 不支援值為 2)。
  • NSParagraphStyleAttributeName 段落
    該屬性所對應的值是一個 NSParagraphStyle 物件。該屬性在一段文字上應用多個屬性。如果不指定該屬性,則預設為 NSParagraphStyle 的defaultParagraphStyle 方法返回的預設段落屬性
  • NSKernAttributeName 字間距
    該屬性所對應的值是一個 NSNumber 物件(整數)。字母緊排指定了用於調整字距的畫素點數。字母緊排的效果依賴於字型。值為 0 表示不使用字母緊排。預設值為0
  • NSStrikethroughStyleAttributeName 刪除線
  • NSUnderlineStyleAttributeName 下劃線
  • NSStrokeColorAttributeName 邊線顏色
    該屬性所對應的值是一個 UIColor 物件。如果該屬性不指定(預設),則等同於 NSForegroundColorAttributeName。否則,指定為刪除線或下劃線顏色。更多細節見“Drawing attributedstrings that are both filled and stroked”
  • NSStrokeWidthAttributeName 邊線寬度
  • NSShadowAttributeName 陰影
  • NSVerticalGlyphFormAttributeName 橫豎排版
    例項
 // 設定顏色等
    NSMutableDictionary *arrDic = [NSMutableDictionary dictionary];
    arrDic[NSForegroundColorAttributeName] = [UIColor purpleColor];
    arrDic[NSBackgroundColorAttributeName] = [UIColor greenColor];
    arrDic[NSKernAttributeName] = @10;
    arrDic[NSUnderlineStyleAttributeName] = @1;
    
    NSMutableAttributedString *attriOneStr = [[NSMutableAttributedString alloc]initWithString:@"來呀,快活呀,反正有大把時光" attributes:arrDic];
    self.oneLabel.attributedText = attriOneStr;
    
    // 簡單的圖文混排
    NSMutableAttributedString *arrTwoStr = [[NSMutableAttributedString alloc]init];
    NSMutableAttributedString *TwoChildStr = [[NSMutableAttributedString alloc]initWithString:@"你好啊"];
    [arrTwoStr appendAttributedString:TwoChildStr];
    
    NSTextAttachment *attachMent = [[NSTextAttachment alloc]init];
    attachMent.image = [UIImage imageNamed:@"2"];
    attachMent.bounds = CGRectMake(0, -5, 20, 20);
    NSAttributedString *picStr = [NSAttributedString attributedStringWithAttachment:attachMent];
    [arrTwoStr appendAttributedString:picStr];
    
    NSAttributedString *TwooStr = [[NSAttributedString alloc]initWithString:@"我是小菜鳥"];
    [arrTwoStr appendAttributedString:TwooStr];
    self.twoLabel.attributedText = arrTwoStr;

效果

694552-c9a265fb233c2595.png
簡單.png

表情鍵盤,富文字實現圖文混排

表情鍵盤

694552-dc932458817ae340.png
Snip20160917_5.png

平常大家用的 QQ,微信等APP中隨處可見表情鍵盤,在做表情鍵盤前,先來了解一下什麼是表情.
日常生活中,所用到的表情一般為兩種--圖片表情,emoji表情
emoji表情的本質就是字串,比如 0x1f601:,在顯示的時候我們需要將字串轉成表情
圖片表情就是一張圖片,比如這是一個表情資訊,我們根據png來載入快取在本地的圖片,並顯示.
694552-a6ff0d24dd9ed42d.png
圖片表情.png

實現思路

考慮到表情的兩種表現形式,決定用 Button 來實現,這樣可以方便的顯示字型或者圖片

  • 初始化一個 ListView, 並新增一個 UIScrollview 子控制元件
  • UIScrollview新增n個(需要幾個表情種類新增幾個) gridView
  • gridView上面新增 Button來顯示錶情

表情鍵盤程式碼###

由於程式碼量較大,這裡上一些核心程式碼,具體程式碼可以下載,下來再看TextKit入門 demo地址
表情工具類載入所需表情

+ (NSArray *)defaultEmotions
{
    if (!_defaultEmotions) {
        NSString *plist = [[NSBundle mainBundle] pathForResource:@"EmotionIcons/default/info.plist" ofType:nil];
        _defaultEmotions = [GPEmotion mj_objectArrayWithFile:plist];
        [_defaultEmotions makeObjectsPerformSelector:@selector(setDirectory:) withObject:@"EmotionIcons/default"];
    }
    return _defaultEmotions;
}

+ (NSArray *)emojiEmotions
{
    if (!_emojiEmotions) {
        NSString *plist = [[NSBundle mainBundle] pathForResource:@"EmotionIcons/emoji/info.plist" ofType:nil];
        _emojiEmotions = [GPEmotion mj_objectArrayWithFile:plist];
        [_emojiEmotions makeObjectsPerformSelector:@selector(setDirectory:) withObject:@"EmotionIcons/emoji"];
    }
    return _emojiEmotions;
}

+ (NSArray *)lxhEmotions
{
    if (!_lxhEmotions) {
        NSString *plist = [[NSBundle mainBundle] pathForResource:@"EmotionIcons/lxh/info.plist" ofType:nil];
        _lxhEmotions = [GPEmotion mj_objectArrayWithFile:plist];
        [_lxhEmotions makeObjectsPerformSelector:@selector(setDirectory:) withObject:@"EmotionIcons/lxh"];
    }
    return _lxhEmotions;
}

+ (NSArray *)recentEmotions
{
    if (!_recentEmotions) {
        _recentEmotions = [NSKeyedUnarchiver unarchiveObjectWithFile:GPRecentFilepath];
        if (!_recentEmotions) {
            _recentEmotions = [NSMutableArray array];
        }
    }
    return _recentEmotions;
}

表情資料傳遞

  • 點選所需表情傳遞給 ListView
  - (void)setEmtiontype:(GPEmtionType)type
{
    switch (type) {
        case GPEmotionTypeRecent: {
            self.listView.emotions = [GPEmtionTool recentEmotions];
            break;
        }
        case GPEmotionTypeDefault: {
            self.listView.emotions = [GPEmtionTool defaultEmotions];
            
            break;
        }
        case GPEmotionTypeEmoji: {
            self.listView.emotions = [GPEmtionTool emojiEmotions];
            break;
        }
        case GPEmotionTypeLxh: {
            self.listView.emotions = [GPEmtionTool lxhEmotions];
            break;
        }
    }
}
  • LIstView 傳遞給GridView
  - (void)setEmotions:(NSArray *)emotions
{
    _emotions = emotions;
    
    NSInteger totlas = (emotions.count + GPEmotionMaxCountPerPage - 1) / GPEmotionMaxCountPerPage;
    NSInteger currrentGridViewCount = self.scrollView.subviews.count;
    
    self.pageControl.numberOfPages = totlas;
    self.pageControl.currentPage = 0;
    GPEmottionGridView *gridView = nil;
    for (NSInteger i = 0; i < totlas; i ++) 
        if (i >= currrentGridViewCount) {
            gridView = [[GPEmottionGridView alloc]init];
            [self.scrollView addSubview:gridView];
        } else {
            gridView = self.scrollView.subviews[i]
        }
        NSInteger loc = i * GPEmotionMaxCountPerPage;
        NSInteger len = GPEmotionMaxCountPerPage;
        if (loc + len > emotions.count) {
            len = emotions.count - loc;
        }
        NSRange range = NSMakeRange(loc, len);
        NSArray *gridViewemotionS = [emotions subarrayWithRange:range];
        gridView.emotions = gridViewemotionS;
        gridView.hidden = NO
    
    for (NSInteger i = totlas; i<currrentGridViewCount; i++) {
        GPEmottionGridView *gridView = self.scrollView.subviews[i];
        gridView.hidden = YES;
    
       [self setNeedsLayout];
    self.scrollView.contentOffset = CGPointZero
  • gridView 傳遞給 btn
  - (void)setEmotions:(NSArray *)emotions
{
    _emotions = emotions;
    
    NSInteger count = emotions.count;
    NSInteger currentEmotionViewCount = self.emotionViews.count;
    for (int i = 0; i<count; i++) {
        GPEmotionView *emotionView = nil;
        
        if (i >= currentEmotionViewCount) {
            emotionView = [[GPEmotionView alloc] init];
            [emotionView addTarget:self action:@selector(emotionClick:)           forControlEvents:UIControlEventTouchUpInside];
            [self addSubview:emotionView];
            [self.emotionViews addObject:emotionView];
        } else {
            emotionView = self.emotionViews[i];
        }
        // 傳遞模型資料
        emotionView.emotion = emotions[i];
       
      for NSInteger i = count; i<currentEmotionViewCount; i++) 
        UIButton *emotionView = self.emotionViews[i];
        emotionView.hidden = YES;
    ```
* Btn 展示表情
  • (void)setEmotion:(GPEmotion *)emotion
    {
    _emotion = emotion;

    if (emotion.code) {
    self.titleLabel.font = [UIFont systemFontOfSize:32];
    [self setTitle:emotion.emoji forState:UIControlStateNormal];
    [self setImage:nil forState:UIControlStateNormal];
    } else { // 圖片表情
    NSString *icon = [NSString stringWithFormat:@"%@/%@", emotion.directory, emotion.png];
    UIImage *image = [UIImage imageNamed:icon];
    [self setImage: [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]forState:UIControlStateNormal];
    [self setTitle:nil forState:UIControlStateNormal];
    }
    }

###圖文混排實現


![Uploading Snip20160917_5_983709.png . . .]](http://upload-images.jianshu.io/upload_images/694552-193ab88b3b973702.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

**實現思路**
* 獲得後臺的字串,然後用正規表示式將字串分割為表情和非表情兩部分,然後將其轉換為**富文字字串**,並在匹配到超連結時候給其繫結一個 key, 隨後將分割後的結果按順序排好,

* 將之前轉換後的富文字字串賦值為 `UITextView` 的`attributedText`屬性

* 點選超連結,判斷當前點是否在連結範圍之內,若在就開啟連結

**圖文混排核心程式碼**

* 普通字串轉換為富文字字串
         - (NSAttributedString *)creatArrtext:(NSString *)text
      { NSArray *regexResults = [GPEmtionTool regexResultsWithText:text];
      NSMutableAttributedString *attributedString =   [[NSMutableAttributedString alloc] init];
       [regexResults enumerateObjectsUsingBlock:^(GPRegexResult *result,   NSUInteger idx, BOOL *stop) {
        GPEmotion *emotion = nil;
        if (result.isEmotion) { // 表情
            emotion = [GPEmtionTool emotionWithDesc:result.string];
        }
        
        if (emotion) { // 如果有表情
            // 建立附件物件
            GPEmotionAttachment *attach = [[GPEmotionAttachment alloc] init];
            
            // 傳遞表情
            attach.emotion = emotion;
            attach.bounds = CGRectMake(0, -3, GPStatusOrginalTextFont.lineHeight, GPStatusOrginalTextFont.lineHeight);
            
            // 將附件包裝成富文字
            NSAttributedString *attachString = [NSAttributedString attributedStringWithAttachment:attach];
            [attributedString appendAttributedString:attachString];
        } else { // 非表情(直接拼接普通文字)
            NSMutableAttributedString *substr = [[NSMutableAttributedString alloc] initWithString:result.string];
        
            // 匹配超連結
            NSString *httpRegex = @"http(s)?://([a-zA-Z|\\\\d]+\\\\.)+[a-zA-Z|\\\\d]+(/[a-zA-Z|\\\\d|\\\\-|\\\\+|_./?%&=]*)?";
            [result.string enumerateStringsMatchedByRegex:httpRegex usingBlock:^(NSInteger captureCount, NSString *const __unsafe_unretained *capturedStrings, const NSRange *capturedRanges, volatile BOOL *const stop) {
                [substr addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:*capturedRanges];
                
                // 繫結一個key
                [substr addAttribute:GPLinkText value:*capturedStrings range:*capturedRanges];
            }];
            
            [attributedString appendAttributedString:substr];
        }
      }];
    
      // 設定字型
      [attributedString addAttribute:NSFontAttributeName   value:GPStatusOrginalTextFont range:NSMakeRange(0,   attributedString.length)];
    
      return attributedString;
      }

* 點選連結跳轉
  • (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
    {
    UITouch *touch = [touches anyObject];
    CGPoint point = [touch locationInView:touch.view];
    CGPoint pp = [self convertPoint:point toView:self.textView];
    GPLink *touchingLink = [self touchingLinkWithPoint:pp];
if (touchingLink) {
    [[NSNotificationCenter defaultCenter] postNotificationName:GPLinkDidSelectedNotification object:nil userInfo:@{GPLinkText : touchingLink.text}];
}

[self touchesCancelled:touches withEvent:event];

}

  • (GPLink *)touchingLinkWithPoint:(CGPoint)point
    {
    __block GPLink *touchingLink = nil;
    [self.links enumerateObjectsUsingBlock:^(GPLink *link, NSUInteger idx, BOOL *stop) {
    for (UITextSelectionRect *selectionRect in link.rects) {
    if (CGRectContainsPoint(selectionRect.rect, point)) {
    NSLog(@"選中%@",NSStringFromCGRect(selectionRect.rect));
    touchingLink = link;
    break;
    }
    }
    }];
    return touchingLink;
    }
# TextKit
![TextKit.png](http://upload-images.jianshu.io/upload_images/694552-21b677318e171048.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
接下來,我們來看今天的重頭戲` TextKit`,首先來看看`textKit` 的類
* `NSTextStorage`: 平時用到的字串 **string**,這個類裡面包含著 string的屬性,比如顏色,大小等都是這個類來管理
* `NSLayoutManager`: 這個就是管理中心,負責佈局渲染
* `NSTextContainer` : 就是可以渲染的範圍
* `UITextView` :就是我們平時用的控制元件,用來給使用者展示資料
那麼,我麼可以用這些類來做哪些事情呢,看一些例項
### 閱讀排版

![閱讀排版.gif](http://upload-images.jianshu.io/upload_images/694552-9463e4514a639b67.gif?imageMogr2/auto-orient/strip)


**閱讀排版實現思路**
* 建立n 個 `textView`,共用一套`NSLayoutManager`

**閱讀排版核心程式碼**
  • (void)setupTextKit
    {
    NSURL *contentUrl = [[NSBundle mainBundle]URLForResource:@"content" withExtension:@"txt"];

    self.textStorage = [[NSTextStorage alloc]initWithFileURL:contentUrl options:[NSDictionary dictionary] documentAttributes:nil error:nil];
    self.layoutManager = [[NSLayoutManager alloc]init];

    [self.textStorage addLayoutManager:self.layoutManager];
    }

  • (void)layoutconter
    {
    NSInteger totlaGlyph = 0;
    CGFloat X = 0;
    while (totlaGlyph < self.layoutManager.numberOfGlyphs) {

      NSTextContainer *textContainer = [[NSTextContainer alloc]initWithSize:CGSizeMake(SCREEN_WIDTH, SCREEN_HEIGHT)];
      
      [self.layoutManager addTextContainer:textContainer];
      
      UITextView *textView = [[UITextView alloc]initWithFrame:CGRectMake(X, 0, SCREEN_WIDTH, self.pageScrollView.height) textContainer:textContainer];
      textView.scrollEnabled = NO;
      textView.font = [UIFont systemFontOfSize:20];
      [self.pageScrollView addSubview:textView];
      
      X += SCREEN_WIDTH;
      
      totlaGlyph = NSMaxRange([self.layoutManager glyphRangeForTextContainer:textContainer]);
    

    }

    CGSize contentSize = CGSizeMake(X, self.pageScrollView.height);
    self.pageScrollView.pagingEnabled = YES;
    self.pageScrollView.contentSize = contentSize;
    self.pageScrollView.showsHorizontalScrollIndicator = NO;

}

### 高亮文字,URL, 保持 URL 在一行是一個整體

**高亮文字,URL實現思路**
* 可以自定義`NSTextStorage`,這裡注意`NSTextStorage`繼承自`NSMutableAttributedString`,所以必須實現以下方法:
`  - (NSString *)string;`
 ` - (NSDictionary *)attributesAtIndex:(NSUInteger)location effectiveRange:(NSRangePointer)range;`
 ` - (void)replaceCharactersInRange:(NSRange)range withString:(NSString *)str;`
 ` - (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range;`

* 在`- (void)processEditing`中匹配高亮字元,匹配 URL, 並高亮
* 在 `NSLayoutManagerDelegate`實現 url 保持整體不換行
**高亮文字,URL核心程式碼**

  • (void)processEditing
    {

    NSRegularExpression *expression = [[NSRegularExpression alloc]initWithPattern:@"a[\\b{Alphabetic}&&\\b{Uppercase}][\\br{Alphabetic}]+" options:NSRegularExpressionCaseInsensitive error:nil];

    NSRange paragaphRange = [self.string paragraphRangeForRange: self.editedRange];
    [self removeAttribute:NSForegroundColorAttributeName range:paragaphRange];

    [expression enumerateMatchesInString:self.string options:0 range:paragaphRange usingBlock:^(NSTextCheckingResult * _Nullable result, NSMatchingFlags flags, BOOL * _Nonnull stop) {
    [self addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:result.range];
    }];
    [super processEditing];
    }

  • (void)replaceCharactersInRange:(NSRange)range withString:(NSString *)str
    {
    [_imp replaceCharactersInRange:range withString:str];
    [self edited:NSTextStorageEditedCharacters range:range changeInLength:(NSInteger)str.length - (NSInteger)range.length];

    NSDataDetector *datector = [[NSDataDetector alloc]initWithTypes:NSTextCheckingTypeLink error:nil];

    NSRange paragaphRange = [self.string paragraphRangeForRange: NSMakeRange(range.location, str.length)];

    [self removeAttribute:NSLinkAttributeName range:paragaphRange];
    [self removeAttribute:NSForegroundColorAttributeName range:paragaphRange];

    [datector enumerateMatchesInString:self.string options:0 range:paragaphRange usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {

      [self addAttribute:NSLinkAttributeName value:result.URL range:result.range];
      [self addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:result.range];
    

    }];
    }


  • (BOOL)layoutManager:(NSLayoutManager *)layoutManager shouldBreakLineByWordBeforeCharacterAtIndex:(NSUInteger)charIndex
    {
    NSRange range;
    NSURL *linkURL = [layoutManager.textStorage attribute:NSLinkAttributeName atIndex:charIndex effectiveRange:&range];

    if (linkURL && charIndex > range.location && charIndex <= NSMaxRange(range))
    return NO;
    else
    return YES;
    }

**機智的你一定發現,其實利用 TextKit也可以實現圖文混排,機智的你自己試一試**
###環繞佈局

![環繞佈局.png](http://upload-images.jianshu.io/upload_images/694552-93d9a2037da33412.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
如圖所示;大家用 Word 的時候插入圖片,使得文字環繞在圖片周圍,哈哈,好訊息來了, iOS 也可以實現哦
**環繞佈局實現思路**
* 記得`textContainer`,我們可以直接給其屬性賦值一個` path`, 就相當於在一張紙上裁剪掉一部分,那麼自然就不會在那部分渲染文字了
**環繞佈局核心程式碼**
  • (void)setupImage
    {

    UIImageView *imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"5"]];
    imageView.center = self.view.center;
    CGRect ofram = [self.textView convertRect:imageView.bounds fromView:imageView];
    ofram.origin.y = ofram.origin.y - 64;
    UIBezierPath *path = [UIBezierPath bezierPathWithRect:ofram];

    self.textView.textContainer.exclusionPaths = @[path];

    [self.view addSubview:imageView];
    }

#總結
這只是一些簡單的使用,機智的你肯定有更多想法,互相學習吧

>參考
[obJc,初始 textKit](https://objccn.io/issue-5-1/)
[MJ](https://github.com/CoderMJLee/MJExtension)

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