Question

In a tab-based app when I switch between some tabs, I sometimes get EXC_BAD_ACCESS. It’s not every time but if you flick back and forward a few times it eventually happens.

Defined in the .h:

NSUserDefaults *theData;

I’ve got this in viewWillAppear and viewWillDisappear:

[theData synchronize];

The line at fault gets called in a function at the viewWillAppear stage:

NSMutableArray *thisArray = [theData objectForKey:@"FriendsArray"];

I’m using NSUserDefaults to store a few dictionaries of data. This is populated by server calls, but there’s no need for an internal database due to it being refreshed often. I am open to other ways of storing this data if that would be better.

I have tried a number of things like casting it (NSMutableArray *)[theData objectForKey:@"FriendsArray"]; or using arrayForKey and a number of other things with no improvement.

Any help or tips would be greatly appreciated.

Answer 1

NSMutableArray *thisArray = [theData objectForKey:@"FriendsArray"]; // retain

The way you try to make an array mutable is wrong. Also written like that, as suggested in the comments, you should probably retain that array.

Try init/alloc a new mutable array with objects like this :

NSMutableArray *thisArray =
 [[NSMutableArray alloc] initWithArray:[theData objectForKey:@"FriendsArray"]];

Another method, -(id)initWithArray:(NSArray *)array copyItems:(BOOL)flag;, allows you to make a copy of the original objects.