Question

I have a method which sends out a request and has a delegate responder. The method is being called by a KVO responder. The code works fine when I call it from viewDidLoad, but when I make the request from the KVO method, it doesn’t trigger the delegate method.

here is my KVO responder:

//observe app delegates userdata to check for when user data is available or data is changed
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context
{
    if ([keyPath isEqualToString:@"userData"] )
    {
        //goto facebook logic
        [self FBFriendSuggester];
    }
}

and the method it calls:

-(void)FBFriendSuggester
{
    NSDictionary * fb_credentials = nil;
    if([prefs objectForKey:@"facebookCredentials"])
    {
        fb_credentials = [prefs objectForKey:@"facebookCredentials"];
        if ([fb_credentials objectForKey:@"expiry"] && [fb_credentials objectForKey:@"fbtoken"]) {
            NSLog(@"found stored Facebook credentials.");
            ApplicationDelegate.facebook.accessToken = [fb_credentials objectForKey:@"fbtoken"];
            ApplicationDelegate.facebook.expirationDate = [fb_credentials objectForKey:@"expiry"];
        }
    }
    if ([ApplicationDelegate.facebook isSessionValid]) {
        printf("_valid facebook\n");
        [ApplicationDelegate.facebook requestWithGraphPath:@"me/friends" andDelegate:self];
    }else
        printf("_invalid facebook\n");
}

and the delegate method:

- (void)request:(FBRequest *)request didLoad:(id)result{
    NSLog(@"result2:%@",result);

    NSDictionary * rawObject = result;
    NSArray * dataArray = [rawObject objectForKey:@"data"];

    for (NSDictionary * f in dataArray) {
        [friends addObject:[[KNSelectorItem alloc] initWithDisplayValue:[f objectForKey:@"name"]
                                                            selectValue:[f objectForKey:@"id"]
                                                               imageUrl:[NSString stringWithFormat:@"http://graph.facebook.com/%@/picture?type=square", [f objectForKey:@"id"]]]];
    }
    [friends sortUsingSelector:@selector(compareByDisplayValue:)];
    [self pickerPopup:self];
}

the delegate method doesn’t get called in this scenario, but it does work fine when i call -(void)FBFriendSuggester directly from the controller. I don’t know what to do, i tried setting a notification to respond in hopes that it would trigger the delegate, but that didn’t work either.

Answer 1

I was able to work around my problem by issuing:

[self performSelectorOnMainThread:@selector(FBFriendSuggester) withObject:nil waitUntilDone:NO];

It would be great to know why this works like this though.