Question

I’m trying to implement a way for users to pick from the Twitter accounts they’ve set up on the iPhone (iOS5 and up). I can get the usernames to appear in a UIActionSheet, but for some reason the UIActionSheet takes about 5 seconds to appear after the method has been called.

I thought perhaps it was because it took a while to retrieve the list of Twitter accounts, but in my log they appear instantly, so it’s not that.

Any ideas?

- (void)TwitterSwitch {
    ACAccountStore *accountStore = [[ACAccountStore alloc] init];

// Create an account type that ensures Twitter accounts are retrieved.
    ACAccountType *accountType = [accountStore accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierTwitter];

    NSMutableArray *buttonsArray = [NSMutableArray array];

// Request access from the user to use their Twitter accounts.
    [accountStore requestAccessToAccountsWithType:accountType withCompletionHandler:^(BOOL granted, NSError *error) {


       // Get the list of Twitter accounts.
        NSArray *accountsArray = [accountStore accountsWithAccountType:accountType];

       NSLog(@"%@", accountsArray);


       [accountsArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {

           [buttonsArray addObject:((ACAccount*)obj).username];
        }];


       NSLog(@"%@", buttonsArray);

        UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles:nil];
        for( NSString *title in buttonsArray)
            [actionSheet addButtonWithTitle:title];
        [actionSheet addButtonWithTitle:@"Cancel"];
        actionSheet.cancelButtonIndex = actionSheet.numberOfButtons-1;
        [actionSheet showFromTabBar:self.tabBarController.tabBar];
}]; 

}

Answer 1

I think the problem might be that in requestAccessToAccountsWithType:withCompletionHandler: the handler can be called on an arbitrary queue, and you’re showing a UI element (the action sheet) from within that handler. Since interaction with the UI should only be done on the main thread, that could be a problem. I tried moving some of the code into another method, and calling it on the main thread — this was much faster:

- (void)TwitterSwitch {
    ACAccountStore *accountStore = [[ACAccountStore alloc] init];

    // Create an account type that ensures Twitter accounts are retrieved.
    ACAccountType *accountType = [accountStore accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierTwitter];


    // Request access from the user to use their Twitter accounts.
    [accountStore requestAccessToAccountsWithType:accountType withCompletionHandler:^(BOOL granted, NSError *error) {


        // Get the list of Twitter accounts.
        NSArray *accountsArray = [accountStore accountsWithAccountType:accountType];

        NSLog(@"%@", accountsArray);
        [self performSelectorOnMainThread:@selector(populateSheetAndShow:) withObject:accountsArray waitUntilDone:NO];
        }];
}

-(void)populateSheetAndShow:(NSArray *) accountsArray {
    NSMutableArray *buttonsArray = [NSMutableArray array];
    [accountsArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {

            [buttonsArray addObject:((ACAccount*)obj).username];
        }];


        NSLog(@"%@", buttonsArray);

        UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles:nil];
        for( NSString *title in buttonsArray)
            [actionSheet addButtonWithTitle:title];
        [actionSheet addButtonWithTitle:@"Cancel"];
        actionSheet.cancelButtonIndex = actionSheet.numberOfButtons-1;
        [actionSheet showInView:self.view];
}

Note that I changed the way I show the sheet because in my test app I didn’t have a tab bar controller.