How to store a CLLocation object using NSKeyedArchiver? - ios

Question

I am slightly confused why the following doesn't work. Can someone enlighten me?
I have one function that returns a filePath:
- (NSString *) lastLocationPersistenceFilePath {
NSString *filePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingString:#"last_location"];
return filePath;
}
Then, in a method triggered by a button, I attempt to save a CLLocation object like so:
// Store this location so it can persist:
BOOL success = [NSKeyedArchiver archiveRootObject:_startLocation toFile:[self lastLocationPersistenceFilePath]];
if (!success) {
NSLog(#"Could not persist location for some reason!");
} else {
NSLog(#"New location has been stored.");
}
In my viewDidLoad:, I attempt to load it:
- (void)viewDidLoad
{
[super viewDidLoad];
// Retrieve last location:
CLLocation *decodedLocation = [NSKeyedUnarchiver unarchiveObjectWithFile:[self lastLocationPersistenceFilePath]];
if (decodedLocation) {
_startLocation = decodedLocation;
} else {
NSLog(#"Decoding failed.");
}
}
The archiving fails which, of course, means I can't decode anything either. I feel like I am missing something obvious/trivial... any pointers?

Answer 1

Simply, it is not possible to write to the the app's resource directory. Instead write to the app's document directory.
Code example"
- (NSString *) lastLocationPersistenceFilePath {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentDirectory = [paths firstObject];
NSString *filePath = [documentDirectory stringByAppendingPathComponent:#"last_location"];
return filePath;
}