iOS emoji表情转码 或者判断

如果项目中有评论或者信息恢复的地方，往往会用到emoji，有时候如后台不支持emoji，就会显示乱码错误，我们可以把emoji转成unicode编码或者utf8编码格式传给服务器。当然如果后台服务器接收的时候能做好判断识别最好，我们这边后台是支持的，我仅记录一下方法，以备不时之需。

先定义一个UITextView 并设置代理

设定一个宏定义，用来判断emoji

 #define MULITTHREEBYTEUTF16TOUNICODE(x,y) (((((x ^ 0xD800) << 2) | ((y ^ 0xDC00) >> 8)) << 8) | ((y ^ 0xDC00) & 0xFF)) + 0x10000

下面写代理方法实现的内容

 - (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
 {
     NSString *hexstr = @"";
 
     for (int i=;i< [text length];i++)
     {
         hexstr = [hexstr stringByAppendingFormat:@"%@",[NSString stringWithFormat:@"0x%1X ",[text characterAtIndex:i]]];
     }
     NSLog(@"UTF16 [%@]",hexstr);
 
     hexstr = @"";
 
     long slen = strlen([text UTF8String]);
 
     for (int i = ; i < slen; i++)
     {
         //fffffff0 去除前面六个F & 0xFF
         hexstr = [hexstr stringByAppendingFormat:@"%@",[NSString stringWithFormat:@"0x%X ",[text UTF8String][i] & 0xFF ]];
     }
     NSLog(@"UTF8 [%@]",hexstr);
 
     hexstr = @"";
 
     if ([text length] >= ) {
 
         for (int i = ; i < [text length] /  && ([text length] %  == ) ; i++)
         {
             // three bytes
             if (([text characterAtIndex:i*] & 0xFF00) ==  ) {
                 hexstr = [hexstr stringByAppendingFormat:@"Ox%1X 0x%1X",[text characterAtIndex:i*],[text characterAtIndex:i*+]];
             }
             else
             {// four bytes
                 hexstr = [hexstr stringByAppendingFormat:@"U+%1X ",MULITTHREEBYTEUTF16TOUNICODE([text characterAtIndex:i*],[text characterAtIndex:i*+])];
             }
 
         }
         NSLog(@"(unicode) [%@]",hexstr);
     }
     else
     {
         NSLog(@"(unicode) U+%1X",[text characterAtIndex:]);
     }
 
     return YES;
 }

在输入的时候，会自动把输入内容转成相应的格式。

如果在有些地方不需要输入emoji表情，可以做相关限制。

我这边用到的是，如果用户输入emoji表情的时候，会给出提示

 //是否含有表情
 - (BOOL)stringContainsEmoji:(NSString *)string
 {
     __block BOOL returnValue = NO;
 
     [string enumerateSubstringsInRange:NSMakeRange(, [string length])
                                options:NSStringEnumerationByComposedCharacterSequences
                             usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
                                 const unichar hs = [substring characterAtIndex:];
                                 if (0xd800 <= hs && hs <= 0xdbff) {
                                     if (substring.length > ) {
                                         const unichar ls = [substring characterAtIndex:];
                                         const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
                                         if (0x1d000 <= uc && uc <= 0x1f77f) {
                                             returnValue = YES;
                                         }
                                     }
                                 } else if (substring.length > ) {
                                     const unichar ls = [substring characterAtIndex:];
                                     if (ls == 0x20e3) {
                                         returnValue = YES;
                                     }
                                 } else {
                                     if (0x2100 <= hs && hs <= 0x27ff) {
                                         returnValue = YES;
                                     } else if (0x2B05 <= hs && hs <= 0x2b07) {
                                         returnValue = YES;
                                     } else if (0x2934 <= hs && hs <= 0x2935) {
                                         returnValue = YES;
                                     } else if (0x3297 <= hs && hs <= 0x3299) {
                                         returnValue = YES;
                                     } else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50) {
                                         returnValue = YES;
                                     }
                                 }
                             }];
 
     return returnValue;
 }

通过调用该方法，如果返回的是YES则输入内容含有emoji，反之。