Question

Save Mechanics I have used:

    NSMutableData *data = [[NSMutableData alloc] init];
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    [archiver encodeObject:self forKey:@"Save"];
    [archiver finishEncoding];
    [data writeToFile:filePath atomically:YES];
    [archiver release];
    [data release];

I have used

[[NSFileManager defaultManager] fileExistsAtPath:savePath];

[[NSFileManager defaultManager] contentsOfDirectoryAtPath:[SynchronizedData createPath] error:&error]

to check the existences of my file. They confirm the file exist.

However I cannot load the file with the same directory path

    //NSData *encodedData = [[NSFileManager defaultManager] contentsAtPath:[SynchronizedData createPath]];

    NSData *encodedData = [[[NSData alloc] initWithContentsOfFile:tempFilePath] autorelease];

    if (encodedData == nil) {
        NSLog(@"Save cannot open while loading!");
        return nil;
    }

The above encodedData, both returned nil. (autorelease is not the problem, i’ve checked)

Any ideas what’s wrong?

I found similar case in previous thread, I tried retain once more my tempFilePath, it doesn’t matter, the problem still exist.

---

I have done the save in a more simpler mechanism than the above one.

The problem remained unsolved for getting the NSData from directory. Maybe due to Read Permission mentioned by @paxdiablo.

Thus I use “Documents” folder instead of “Library”. The NSData open has no error.

Answer 1

A file can exist but still not be readable. You should probably start by checking the permissions on that file.

Also, use the initWithContentsOfFile:options:error: variant to get an error back – that should hopefully tell you if there’s a problem.

And, based on your comment that you’re seeing:

Cocoa error 257

it appears the permissions are the problem. If you look at the Foundation constants, you’ll see:

NSFileReadNoPermissionError = 257

meaning that you have no permission to read that file.