最近项目需求，要实现一个类似微信的的表情输入，于是把微信的表情扒拉出来，实现了一把。可以从这里下载源码。看起来表情输入没有多少东西，不外乎就是用NSTextAttachment来实现图文混排，结果在实现的过程中遇到了很多小问题，接下来会一一介绍遇到过的坑。先上一张效果图：
一、实现表情选择View(WKExpressionView)
具体的实现就不细说了，主要功能就是点击表情时，将对应表情的图片名称通知给delegate。
二、实现表情textView(WKExpressionTextView)
WKExpressionTextView继承自UITextView, 提供
- (void)setExpressionWithImageName:(NSString *)imageName fontSize:(CGFloat)fontSize方法，用于根据图片插入表情。 具体实现：
//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];//在当前编辑位置插入字符串[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继承自NSTextAttachment, 并新增text字段，为了保存表情对应的文本，用于复制粘贴操作。
@interface WKExpressionTextAttachment : NSTextAttachment@property (nonatomic, copy) NSString *text;@end
WKExpressionTool的提供将普通字符串转换为富文本的方法，主要用于复制时生成表情。
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;}/*** 通过表情生成富文本** @param expressionString 表情名* @param fontSize 对应字体大小** @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，基本功能实现完成。 接下来说说遇到的小问题
编辑是应该对应selectedRange
复制粘贴操作需要重新实现
textView在插入NSTextAttachment后，会默认把font的size修改为12，需要记录默认的size
对应selectedRange操作
具体的操作查看源码
重新实现copy、cut方法
进行复制、粘贴操作会发现，不能对图片进行复制，所以需要自己重写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];}记录默认font的size
利用实例变量defaultFontSize，在WKExpressionTextView实例化时记录self.font.pointSize，以后需要取font的size时，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;}以上所述是小编给大家介绍的iOS高仿微信表情输入功能代码分享，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对VEVB武林网网站的支持！
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