Question

In my AppDelegate, near the end of the init method, I call a [self setup] method. This method gets a string from a URL, trims it, and assigns the string to a property called _songDirectory.

Here’s how it looks in the header file:

@property (retain) NSString *_songDirectory;

And here is how it is assigned in the [setup] method:

//set a URL string
NSString *urlString = [NSString stringWithFormat:@"http://www.blahblahblah.com/php/dev/blah.php?routine=blah"];

NSMutableString *infoString = [self getInfoStringFromURL: urlString];

//get the song directory as a string from the infostring
NSRange startIndex = [infoString rangeOfString:@"song_directory=="];
NSRange endIndex = [infoString rangeOfString:@"end_of_data=="];

_songDirectory = [NSString stringWithString: [infoString substringWithRange: NSMakeRange(startIndex.location + startIndex.length, endIndex.location - startIndex.location - startIndex.length)]];

NSLog(@"STRING IN APP DELEGATE: %@", _songDirectory);

NSLog prints the correct string when called in the app delegate. However, after I push a new scene I cannot access _songDirectory from it. The following code in the pushed scene yields EXC_BAD_ACCESS:

NSLog(@"STRING IN PUSHED SCENE: %@", [[[UIApplication sharedApplication] delegate] _songDirectory]);

I can use the above statement to get ints from the app delegate but not strings. I would appreciate some insight!

Answer 1

You’re assigning the string directly to the instance variable and not to the property, therefore the string is not retained. It should be self._songDirectory = ... instead of _songDirectory (and you should probably call the property songDirectory, the leading underscore is usually only used for private instance variables).