index 0 beyond bounds for empty array - Found array but how to fix?

Question

It appears my code runs fine, but if no Twitter Accounts are stored in the device, the app will crash with this error Terminating app due to uncaught exception 'NSRangeException', reason: '* -[__NSArrayI objectAtIndex:]: index 0 beyond bounds for empty array'

- (void)viewDidLoad
{
    ACAccountStore *accountStore = [[ACAccountStore alloc] init];
    if (accountStore != nil)
    {
        ACAccountType *accountType = [accountStore accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierTwitter];
        if (accountType != nil)
        {
            [accountStore requestAccessToAccountsWithType:accountType options:nil completion:^(BOOL granted, NSError *error) {
                if (granted)
                {
                    NSArray *twitterAccounts = [accountStore accountsWithAccountType:accountType];
                    if (twitterAccounts != nil)
                    {

                        ACAccount *currentAccount = [twitterAccounts objectAtIndex:0];
                        if (currentAccount != nil)
                        {
                            NSString *friendListString = @"https://api.twitter.com/1.1/friends/list.json?cursor=-1&skip_status=true&include_user_entities=false";


                            SLRequest *request = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodGET URL:[NSURL URLWithString:friendListString] parameters:nil];
                            if (request != nil)
                            {
                                // 1.1 api requires a user to be logged in.
                                [request setAccount:currentAccount];
                                [request performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {
                                    NSInteger responseCode = [urlResponse statusCode];
                                    if (responseCode == 200)
                                    {
                                    // ADD STUFFS HERE

                                            }

                                            [theCollectionView reloadData];

                                        }
                                    } 
                                }];
                            }
                        }
                    }
                }
                else
                {
                    NSLog(@"User did not grant access.");
                }

            }];
        } 
    } 
    [super viewDidLoad];
}

I'm not sure why, as I do have the nil check as seen above once it's created? ACAccount *currentAccount = [twitterAccounts objectAtIndex:0]; How would I display an UIAlertView or something similar if no accounts are found on device, rather then having it crash?

Simply check if([twitterAccounts count] > 0) then do your work otherwise array is empty. — TheTiger
– TheTiger, Commented Oct 10, 2013 at 4:13
To checking if(twitterAccounts!=nil) doesn't check if there is index available to fetch the object. It just check twitterAccounts have been initialized or not. While the error is saying that there is no index 0 available in twitterAccounts. So for that if ([twitterAccounts count] > index){NSLog(@"%@",twitterAccounts[index])}. Thats it!! — TheTiger
– TheTiger, Commented Oct 10, 2013 at 8:08

Hanky Panky · Accepted Answer · 2013-10-10 04:10:54Z

2

Change your if to only execute when your array has objects in it, that you can check with count

if (twitterAccounts.count)

answered Oct 10, 2013 at 4:10

Hanky Panky

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1 Comment

TheTiger Over a year ago

This if condition will be FALSE if array is empty.

rmaddy · Accepted Answer · 2013-10-10 04:10:21Z

0

You call ACAccount *currentAccount = [twitterAccounts objectAtIndex:0]; without first checking to see if there are any accounts.

One option would be to change:

if (twitterAccounts != nil)

to:

if (twitterAccounts.count) {
    // process the account
} else {
    // show alert
}

answered Oct 10, 2013 at 4:10

rmaddy

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Comments

Boris Vidolov · Accepted Answer · 2013-10-10 04:31:58Z

0

Consider changing the original code from

 if (twitterAccounts != nil)

to

if (twitterAccounts != nil && twitterAccounts.count)

answered Oct 10, 2013 at 4:31

Boris Vidolov

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