why iOS App terminating due to NSRangeException

Question

I'm having a weird error popping up. It's listing that my app is

Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 0 beyond bounds for empty array'

What puzzles me is that the app runs perfectly fine in the simulator, but when I go to test it on my device I get that error. I've isolated the problem to the line of code below:

updatingTracker = [userDatas objectAtIndex:repeatCount];

Here is the rest of the relevant code:

[self getUserDatas];
[self timerDidFire];

-(void) getUserDatas
{
    userDatas = [[NSMutableArray alloc] init];
    NSUserDefaults *userdef = [NSUserDefaults standardUserDefaults];
    int count = [[userdef objectForKey:@"user_count"] intValue];
    for(int i=0;i<count;i++)
    {
        NewTracker *newtrack=[[NewTracker alloc] init];
        newtrack.FromCurrency = [userdef objectForKey:[NSString stringWithFormat:@"from_string_%d",i]];
        newtrack.ToCurrency   = [userdef objectForKey:[NSString stringWithFormat:@"to_string_%d",i]];
        newtrack.savedCurrency = [userdef objectForKey:[NSString stringWithFormat:@"save_currency_%d",i]];
        newtrack.userTarget = [userdef objectForKey:[NSString stringWithFormat:@"user_target_%d",i]];
        newtrack.trackerId = [userdef objectForKey:[NSString stringWithFormat:@"tracker_id_%d",i]];
        newtrack.realtimeBase = [userdef objectForKey:[NSString stringWithFormat:@"realtime_base_%d",i]];
        newtrack.realtimeTarget = [userdef objectForKey:[NSString stringWithFormat:@"realtime_target_%d",i]];
        newtrack.realtimeUSD = [userdef objectForKey:[NSString stringWithFormat:@"realtime_USD_%d",i]];
        [userDatas addObject:newtrack];
    }
}

- (void) timerDidFire
{
    NSLog(@"bug finder");

    updatingTracker = [userDatas objectAtIndex:repeatCount];
    [self chartconnectionStart:@"3m"];
}

Any ideas or help on why this is happening or how to fix it would be appreciated.

The error message is telling you exactly what's wrong. `count` is probably being set as 0 so you allocate your array but never add any objects to it, and when you try and access it you get the `NSRangeException` error. Try with `int count = 10` and see what happens - if it works you know where to look next. — Rog, Dec 31 '13 at 01:36
Thanks, that did the trick. Caused other errors but now I at least understand what's going on. Appreciate it! — user3147995, Dec 31 '13 at 01:51

score 0 · Accepted Answer · answered Dec 31 '13 at 01:39

0

Your userDatas array is empty. You most likely don't have anything populated in your user defaults on your phone, so the code that adds to the array is never executed. You probably have some data already populated on your simulator and that's why it's not working on the phone

answered Dec 31 '13 at 01:39

Ovi Tisler

6,425
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1

That's exactly it. Thanks! – user3147995 Dec 31 '13 at 01:50
1

I commented out the line [self timerDidFire] and it completely fixed the app. It shouldn't have been firing on app launch because like you said, there is no data in the user defaults. – user3147995 Dec 31 '13 at 02:01

score 0 · Answer 2 · answered Dec 31 '13 at 01:44

0

Simple put a conditional breakpoint on that line for the condition [userDatas count] == 0. Or put in an if to catch that and a breakpoint on it. They use the debugger to figure out how you got there and what the associated values are.

Basic debugging.

answered Dec 31 '13 at 01:44

zaph

111,848
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score 0 · Answer 3 · answered Jan 02 '14 at 09:01

0

Code like this

(void) timerDidFire{

NSLog(@"bug finder");

if([userDatas count]>0){

updatingTracker = [userDatas objectAtIndex:repeatCount];

[self chartconnectionStart:@"3m"];

}

}

Happy coding..........

answered Jan 02 '14 at 09:01

Ravindra Singh

50
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why iOS App terminating due to NSRangeException

3 Answers3