最近項目需求，要實現一個類似微信的的表情輸入，于是把微信的表情扒拉出來，實現了一把。可以從這里下載源碼。看起來表情輸入沒有多少東西，不外乎就是用NSTextAttachment來實現圖文混排，結果在實現的過程中遇到了很多小問題，接下來會一一介紹遇到過的坑。先上一張效果圖：
一、實現表情選擇View(WKExpressionView)
具體的實現就不細說了，主要功能就是點擊表情時，將對應表情的圖片名稱通知給delegate。
二、實現表情textView(WKExpressionTextView)
WKExpressionTextView繼承自UITextView, 提供
- (void)setExpressionWithImageName:(NSString *)imageName fontSize:(CGFloat)fontSize方法，用于根據圖片插入表情。 具體實現：
//富文本WKExpressionTextAttachment *attachment = [[WKExpressionTextAttachment alloc] initWithData:nil ofType:nil];UIImage *image = [UIImage imageNamed:imageName];attachment.image = image;attachment.text = [WKExpressionTool getExpressionStringWithImageName:imageName];attachment.bounds = CGRectMake(0, 0, fontSize, fontSize);NSAttributedString *insertAttributeStr = [NSAttributedString attributedStringWithAttachment:attachment];NSMutableAttributedString *resultAttrString = [[NSMutableAttributedString alloc] initWithAttributedString:self.attributedText];//在當前編輯位置插入字符串[resultAttrString insertAttributedString:insertAttributeStr atIndex:self.selectedRange.location];NSRange tempRange = self.selectedRange;self.attributedText = resultAttrString;self.selectedRange = NSMakeRange(tempRange.location + 1, 0);[self.textStorage addAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:_defaultFontSize]} range:NSMakeRange(0, self.attributedText.length)];[self scrollRangeToVisible:self.selectedRange];[self textChanged];其中WKExpressionTextAttachment繼承自NSTextAttachment, 并新增text字段，為了保存表情對應的文本，用于復制粘貼操作。
@interface WKExpressionTextAttachment : NSTextAttachment@property (nonatomic, copy) NSString *text;@end
WKExpressionTool的提供將普通字符串轉換為富文本的方法，主要用于復制時生成表情。
主要方法
+ (NSAttributedString *)generateAttributeStringWithOriginalString:(NSString *)originalString fontSize:(CGFloat)fontSize{NSError *error = NULL;NSMutableAttributedString *resultAttrString = [[NSMutableAttributedString alloc] initWithString:originalString];NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"//[[a-zA-Z0-9/u4e00-/u9fa5]{1,}//]" options:NSRegularExpressionAllowCommentsAndWhitespace error:&error];NSArray *results = [regex matchesInString:originalString options:NSMatchingReportCompletion range:NSMakeRange(0, originalString.length)];if (results) {for (NSTextCheckingResult *result in results.reverseObjectEnumerator) {NSRange resultRange = [result rangeAtIndex:0];NSString *stringResult = [originalString substringWithRange:resultRange];NSLog(@"%s %@/n", __FUNCTION__, stringResult);NSAttributedString *expressionAttrString = [self getAttributeStringWithExpressionString:stringResult fontSize:fontSize];[resultAttrString replaceCharactersInRange:resultRange withAttributedString:expressionAttrString];}}return resultAttrString;}/*** 通過表情生成富文本** @param expressionString 表情名* @param fontSize 對應字體大小** @return 富文本*/+ (NSAttributedString *)getAttributeStringWithExpressionString:(NSString *)expressionString fontSize:(CGFloat)fontSize{NSString *imageName = [self getExpressionStringWithImageName:expressionString];WKExpressionTextAttachment *attachment = [[WKExpressionTextAttachment alloc] initWithData:nil ofType:nil];UIImage *image = [UIImage imageNamed:imageName];attachment.image = image;attachment.text = [WKExpressionTool getExpressionStringWithImageName:imageName];attachment.bounds = CGRectMake(0, 0, fontSize, fontSize);NSAttributedString *appendAttributeStr = [NSAttributedString attributedStringWithAttachment:attachment];return appendAttributeStr;}至此，基本功能實現完成。 接下來說說遇到的小問題
編輯是應該對應selectedRange
復制粘貼操作需要重新實現
textView在插入NSTextAttachment后，會默認把font的size修改為12，需要記錄默認的size
對應selectedRange操作
具體的操作查看源碼
重新實現copy、cut方法
進行復制、粘貼操作會發現，不能對圖片進行復制，所以需要自己重寫copy、cut方法
- (void)copy:(id)sender{NSAttributedString *selectedString = [self.attributedText attributedSubstringFromRange:self.selectedRange];NSString *copyString = [self parseAttributeTextToNormalString:selectedString];UIPasteboard *pboard = [UIPasteboard generalPasteboard];if (copyString.length != 0) {pboard.string = copyString;}}- (void)cut:(id)sender{[self copy:sender];NSMutableAttributedString *originalString = [[NSMutableAttributedString alloc] initWithAttributedString:self.attributedText];[originalString deleteCharactersInRange:self.selectedRange];self.attributedText = originalString;NSLog(@"--%@", NSStringFromRange(self.selectedRange));[self textChanged];}記錄默認font的size
利用實例變量defaultFontSize，在WKExpressionTextView實例化時記錄self.font.pointSize，以后需要取font的size時，直接取defaultFontSize
@interface WKExpressionTextView : UITextView@property (nonatomic, assign) CGFloat defaultFontSize;@end@implementation WKExpressionTextView{CGFloat _defaultFontSize;}- (void)awakeFromNib{[self setup];}- (instancetype)initWithFrame:(CGRect)frame{self = [super initWithFrame:frame];if (self) {[self setup];}return self;}- (void)setup{[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChange:) name:UITextViewTextDidChangeNotification object:self];_defaultFontSize = self.font.pointSize;self.delegate = self;}以上所述是小編給大家介紹的iOS高仿微信表情輸入功能代碼分享，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對VEVB武林網網站的支持！
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