NSUserDefaults is not always saving my NSString data

Question

I'm running into something a bit puzzling. I have some basic string data that I'm trying to save to the NSUserDefaults, like so:

NSString *state = @"finished";
[[NSUserDefaults standardUserDefaults] setObject:state forKey:@"downloadFinished"];
[[NSUserDefaults standardUserDefaults] synchronize];

When the app starts, one of the ways it makes decisions on which view to load is to check the value of this user setting:

NSString *savedState = [[NSUserDefaults standardUserDefaults] stringForKey:@"downloadFinished"]
if(savedState && [savedState length]) {
  // Show view
}

Every once in a while, I've noticed that this value fails to load, even though I know for sure that this value was saved previously (or at least, the app tried to save it previously). When this happens, I'm getting a nil value back when I lookup the "downloadFinished" key from the user defaults.

Has anyone run into this before? Is there any knowledge out there on why this might happen? How likely is it that the save to the user's defaults cache and defaults database fails, and is there anyway to further prevent this from happening?

I'm going to try the solution mentioned in Why is NSUserDefaults not saving my values?, which forces another synchronize when the app enters the background, but I'm wondering if anyone has deeper knowledge on the matter.

not a solution here but why not use a BOOL value for your `downloadFinished` key? — Michael Dautermann, Jan 27 '12 at 00:57
Are you getting nil or an empty string from your stringForKey: call? According to the documentation, nil indicates the key was not found in NSUserDefaults. — bneely, Jan 27 '12 at 01:15
@MichaelDautermann the downloadFinished is an example -- I'm actually trying to save a string. — dreadpirateryan, Jan 27 '12 at 19:04
@bneely I'm getting a nil back. Yes, I believe that's true -- the key was not found, which tells me that the synchronize didn't complete correctly. — dreadpirateryan, Jan 27 '12 at 19:05
Have you reproduced this on a device, in the simulator, or both? — bneely, Jan 27 '12 at 20:42

score 0 · Answer 1 · answered Jan 27 '12 at 03:06

0

I am guessing some data type issue here. Can you try this instead, and see if you get something?

NSString *savedState = [[NSUserDefaults standardUserDefaults] objectForKey:@"downloadFinished"]

Notice objectForKey usage

answered Jan 27 '12 at 03:06

mbh

3,302
2
22
24

I'll give that a shot. If it works, it's concerning that objectForKey would work when stringForKey doesn't. The data is definitely saved as an NSString. – dreadpirateryan Jan 27 '12 at 19:06

NSUserDefaults is not always saving my NSString data

1 Answers1