Question

I am encoding my object and saving it to a file as follows:
[NSKeyedArchiver archiveRootObject:self.parent toFile:@"gameScene.plist"];

and decoding it as follow:
scene = [[NSKeyedUnarchiver unarchiveObjectWithFile:@"gameScene.plist"] retain];

In simulator the above decoding code invokes my class’s initWithCoder method properly. But when I run the same in device, the ‘initWithCoderis not called nor theinit` method and a ‘nil’ object is returned.

Could anyone please explain whats wrong here?

EDIT: For testing purposes, I gave same set of statements in both init and initWithCoder, instead of decoding the subobjects in initWithCoder and commented out all the encoding in my encodeWithCoder.

Answer 1

Maybe because you can’t write to the root directory on an iOS device? I think that a path of @"gameScene.plist" really means /gameScene.plist, which is not writable on an iOS device, but would be allowed on OS X. The -archiveRootObject:toFile: method is probably returning NO here, indicating that the file wasn’t created successfully.

You may want to do something similar to this:

NSURL *documentsURL = (NSURL *) [[[NSFileManager defaultManager] URLsForDirectory: NSDocumentDirectory inDomains: NSUserDomainMask] lastObject];
NSString *filePath = [[documentsURL path] stringByAppendingPathComponent: @"gameScene.plist"];

BOOL success = [NSKeyedArchiver archiveRootObject: self.parent toFile: filePath];
NSLog(@"Archive Success... %s", (success) ? "YES" : "NO");

NSLog(@"File Exists... %s", [[NSFileManager defaultManager] fileExistsAtPath: filePath] ? "YES" : "NO");

id unarchivedObject = [[NSKeyedUnarchiver unarchiveObjectWithFile: filePath] retain];
NSLog(@"Unarchive Success... %s", (unarchivedObject != nil) ? "YES" : "NO");
NSLog(@"Equal Objects... %s", [self.parent isEqual: unarchivedObject] ? "YES" : "NO");