Updating label on the main thread is not working

Question

I'm trying to update a label while different tasks are proceeding. I searched and used different options and endup using this way but it still doesn't work:

[processStatusLable performSelectorOnMainThread:@selector(setText:) withObject:@"Creating your account..." waitUntilDone:NO];
DCConnector *dccon = [DCConnector new];
ContactsConnector *conCon = [ContactsConnector new];

if (![dccon existUsersData]) {
    [dccon saveUsersInformation:device :usDTO];
    //created account

    //get friends -> Server call
    [processStatusLable performSelectorOnMainThread:@selector(setText:) withObject:@"Checking for friends..." waitUntilDone:NO];
    NSMutableArray *array = [conCon getAllContactsOnPhone];
    // save friends
    [processStatusLable performSelectorOnMainThread:@selector(setText:) withObject:@"Saving friends.." waitUntilDone:NO];
    if ([dccon saveContacts:array]) {
        [processStatusLable performSelectorOnMainThread:@selector(setText:) withObject:@"Friends saved successfully.." waitUntilDone:NO];
    }
}

The last performSelector is getting executed (at least I see the label text changed on the view), but all other selectors are not working. Any idea why?

EDIT 1

- (void)updateLabelText:(NSString *)newText {
    processStatusLable.text = newText;
}

Answer 1

we can use the following code to run something on the main thread,

dispatch_async(dispatch_get_main_queue(), ^{
  //set text label
});

Using that we can write a method like this,

- (void)updateLabelText:(NSString *)newText {    
    dispatch_async(dispatch_get_main_queue(), ^{
       processStatusLable.text = newText;
    });   
}

Finally, you can use change your code this way,

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

    [self updateLabelText:@"Creating your account..."];
    DCConnector *dccon = [DCConnector new];
    ContactsConnector *conCon = [ContactsConnector new];

    if (![dccon existUsersData]) {
        [dccon saveUsersInformation:device :usDTO];
        //created account

        //get friends -> Server call
        [self updateLabelText:@"Checking for friends..."];
        NSMutableArray *array = [conCon getAllContactsOnPhone];
        // save friends
        [self updateLabelText:@"Saving friends.."];
        if ([dccon saveContacts:array]) {
        [self updateLabelText:@"Friends saved successfully.."];
        }
    }
});