NSString to Emoji Unicode - ios

Question

I am trying to pull an JSON file from the backend containing unicodes for emoji. These are not the legacy unicodes (example: \ue415), but rather unicodes that work cross platform (example: \U0001F604).
Here is a sample piece of the json getting pulled:
[
{
"unicode": "U0001F601",
"meaning": "Argh!"
},
{
"unicode": "U0001F602",
"meaning": "Laughing so hard"
}
]
I am having difficulty converting these strings into unicodes that will display as emoji within the app.
Any help is greatly appreciated!

Answer 1

In order to convert these unicode characters into NSString you will need to get bytes of those unicode characters.
After getting bytes, it is easy to initialize an NSString with bytes. Below code does exactly what you want. It assumes jsonArray is the NSArray generated from your json getting pulled.
// initialize using json serialization (possibly NSJSONSerialization)
NSArray *jsonArray;
[jsonArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
NSString *charCode = obj[#"unicode"];
// remove prefix 'U'
charCode = [charCode substringFromIndex:1];
unsigned unicodeInt = 0;
//convert unicode character to int
[[NSScanner scannerWithString:charCode] scanHexInt:&unicodeInt];
//convert this integer to a char array (bytes)
char chars[4];
int len = 4;
chars[0] = (unicodeInt >> 24) & (1 << 24) - 1;
chars[1] = (unicodeInt >> 16) & (1 << 16) - 1;
chars[2] = (unicodeInt >> 8) & (1 << 8) - 1;
chars[3] = unicodeInt & (1 << 8) - 1;
NSString *unicodeString = [[NSString alloc] initWithBytes:chars
length:len
encoding:NSUTF32StringEncoding];
NSLog(#"%# - %#", obj[#"meaning"], unicodeString);
}];