How to Create UIImage from NSData and Avatar Data of XMPP?

Question

This question is related to Iphone SDK, NSData and UIImage.

I am trying to create an image from the Avatar Data returned from the xmpp like the following:

<presence from='yyy@184.73.164.51/spark' to='ken@184.73.164.51/424978324712783686768453' id='Oj02v-45'><status>Away due to idle.</status><priority>0</priority><show>away</show><x xmlns='vcard-temp:x:update'><photo>a3f549fa9705e7ead2905de0b6a804227ecdd404</photo></x><x xmlns='jabber:x:avatar'><hash>a3f549fa9705e7ead2905de0b6a804227ecdd404</hash></x></presence>

So in this case, I assume that a3f549fa9705e7ead2905de0b6a804227ecdd404 is the photo data. So How can I transfer this into NSData?

I think if I can get the NSData object, I can easily create the UIImage, right?

I think "a3f549fa9705e7ead2905de0b6a804227ecdd404" is the photo data this is my codes:

NSString* command = @"a3f549fa9705e7ead2905de0b6a804227ecdd404";
command = [command stringByReplacingOccurrencesOfString:@" " withString:@""];
NSMutableData *commandToSend= [[NSMutableData alloc] init];
unsigned char whole_byte;
char byte_chars[3] = {'\0','\0','\0'};
int i;
for (i=0; i < [command length]/2; i++) {
    byte_chars[0] = [command characterAtIndex:i*2];
    byte_chars[1] = [command characterAtIndex:i*2+1];
    whole_byte = strtol(byte_chars, NULL, 16);
    [commandToSend appendBytes:&whole_byte length:1]; 
}

UIImage *image = [UIImage imageWithData: commandToSend];

However, it doesn't work. Anyone knows what's wrong with it?

Raj Raj · Accepted Answer · 2011-03-04T13:18:36

In XMPPPresence.m add this method

-(NSString *)photo {
    NSXMLElement *xElement = [self elementForName:@"x" xmlns:@"vcard-temp:x:update"];
    NSString *photoHash = [[xElement elementForName:@"photo"]stringValue];
    return photoHash;

}

// In XMPPStream's delegate:

- (void)xmppStream:(XMPPStream *)stream didReceivePresence:
(XMPPPresence *)presence {
        NSString *photoHash = [presence photo];
        if ([photoHash length] > 0) {   // in case when there's no photo hash
                XMPPJID *rosterJID = [presence from];
                BOOL requestPhoto = ... // determine if you need to request new
photo or nor
                if (requestPhoto) {
                        NSXMLElement *iqAvatar = [NSXMLElement elementWithName:@"iq"];

                        NSXMLElement *queryAvatar = [NSXMLElement elementWithName:@"vCard"
xmlns:@"vcard-temp"];
                        [iqAvatar addAttributeWithName:@"type" stringValue:@"get"];
                        [iqAvatar addAttributeWithName:@"to" stringValue:[rosterJID full]];
                        [iqAvatar addChild:queryAvatar];

                        XMPPIQ *avatarRequestIQ = [XMPPIQ iqFromElement:iqAvatar];
                        [stream sendElement:avatarRequestIQ];
                }
        }

}

// And when buddy will send photo, it will be in vcard BASE64-encoded. // You will receive it as IQ:

- (BOOL)xmppStream:(XMPPStream *)stream didReceiveIQ:(XMPPIQ *)iq {
        XMPPElement *vCardPhotoElement = (XMPPElement *)[[iq
elementForName:@"vCard"] elementForName:@"PHOTO"];
        if (vCardPhotoElement != nil) {
                // avatar data
                NSString *base64DataString = [[vCardPhotoElement
elementForName:@"BINVAL"] stringValue];
                NSData *imageData = [NSData
dataFromBase64String:base64DataString];   // you need to get NSData
BASE64 category
                UIImage *avatarImage = [UIImage imageWithData:imageData];

                XMPPJID *senderJID = [iq from];
                [self xmppStream:stream didReceiveImage:avatarImage
forBuddy:senderJID];   // this is my custom delegate method where I
save new avatar to cache
        }
        return NO;

}

Hope this will help you.

How to Create UIImage from NSData and Avatar Data of XMPP?

2 Answers