How to get Custom Text Equivalent of NSAttributedString containing UIImage?

Question

I have a chat application where I need to send Images(Emoticons) along with text.
Now, I can add image via NSTextAttachment (Below Code)

NSTextAttachment *textAttachment = [[NSTextAttachment alloc] init];
NSString *img=[NSString stringWithFormat:@"%@.png",imgName];
textAttachment.image =[UIImage imageNamed:img];

NSAttributedString *attrStringWithImage = [NSAttributedString attributedStringWithAttachment:textAttachment];
NSMutableAttributedString *nStr=[[NSMutableAttributedString alloc]initWithAttributedString:_txtChat.attributedText];
[nStr appendAttributedString:attrStringWithImage];
_txtChat.attributedText  =nStr;

Now, what I want is to attach a custom text say ":)" to the smile icon so that when calling _txtChat.text would return :) instead of the UIImage. So, If the user sees Hii <Smilie>, I would get "Hii :)". I am unable to figure if it is possible to get.

Answer 1

Got the solution myself. We need to do the following :-
1. To retrieve the contents, we need to add a method (richText) to UITextView(customCategory) say UITextView(RichText) (text is already there so I recommend richText)in order to retrieve the desired text values.
2. Save the custom text into the NSTextAttachment. This was done by subclassing NSTextAttachment (into customNSTextAttatchment) and adding an @property id custom.

Now, after creation of customNSTextAttachment(similarly as the code in my question), we can assign our desired NSString into custom.

To retrieve, we do the following:

@implementation UITextView(RichText)
-(NSString*)richText
{ 
  __block NSString *str=self.attributedText.string; //Trivial String representation
  __block NSMutableString *final=[NSMutableString new]; //To store customized text
[self.attributedText enumerateAttributesInRange:NSMakeRange(0, self.attributedText.length) options:0 usingBlock:
 ^(NSDictionary *attributes, NSRange range, BOOL *stop) { 
      //enumerate through the attributes
     NSString *v;
     NSObject* x=[attributes valueForKey:@"NSAttachment"]; 
     if(x) //YES= This is an attachment
     {
         v=x.custom; // Get Custom value (i.e. the previously stored NSString).
         if(v==nil) v=@"";
     }
     else v=[str substringWithRange:range]; //NO=This is a text block.
     [final appendString:v]; //Append the value
 }];

return final;

}