Question

I’m doing:

NSString *current_path = [[NSBundle mainBundle] bundlePath];

NSString *string_path = [NSString stringWithFormat:
                                    @"%@/filedstring", current_path];

my_string_ = [[NSKeyedUnarchiver unarchiveObjectWithFile:string_path] retain];

The archived string is the text from a UITextField which we unarchive here. I’ve tried with and without current_path.

This all works fine when running in simulator (class member NSString *my_string_ is not nil) but when run on my iPhone my_string_ is nil.

Why is that?

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Thanks for the quick responses all.

Adding to Jason Coco’s answer, archive to and unarchive here:

NSString *library_path = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,
                                         NSUserDomainMask, YES) objectAtIndex:0];
NSString *username_path = [library_path 
                           stringByAppendingPathComponent:@"Caches/filedstring"];

Answer 1

You can’t write into the main bundle on the phone, it’s not allowed. That’s why you don’t find your archive there later. The simulator, since it actually runs on Mac OS X doesn’t work this way, so it will actually write the file.

If you need to write something, you have to use one of the writeable paths available to your application. For more information, see the iOS Application Programming Guide / The File System. If you’re going to do iOS Application Development, you should definitely read and understand this entire document.