Emoji characters cannot be encoded to JSON

Please use the below code to encode emoji character

NSString *uniText = [NSString stringWithUTF8String:[textview.text UTF8String]];
NSData *msgData = [uniText dataUsingEncoding:NSNonLossyASCIIStringEncoding];
NSString *goodMsg = [[NSString alloc] initWithData:msgData encoding:NSUTF8StringEncoding] ;

And the below code to decode and display in UILabel

const char *jsonString = [body UTF8String];
NSData *jsonData = [NSData dataWithBytes:jsonString length:strlen(jsonString)];
NSString *goodMsg = [[NSString alloc] initWithData:jsonData encoding:NSNonLossyASCIIStringEncoding];

转自stackoverflow的问题和回答