NSArray writeToFile fails

Question

Hi

I am trying to save an array, which has some dictionaries inside, to a plist file but it fails. I don't get any errors. I do exactly the same few lines above in the code just with another array and that works.. I can't figure out why it does not save the file.

This is where I save the file: (see some debugger output below)

// When built parse through dictionary and save to file
    for ( NSString *keys in [dicByCountry allKeys] )
    {
        NSArray *arrr = [[NSArray alloc] initWithArray:[dicByCountry objectForKey:keys]];
        NSString *fname = [self filePath:[NSString stringWithFormat:@"regions.cid%@.plist",keys]];
        if (![arrr writeToFile:fname atomically:YES])
            NSLog(@"Could not write file regions.cid%@.plist",keys);
    }

Here some GDB Output

(gdb) po fname
/Users/chris/Library/Application Support/iPhone Simulator/4.0/Applications/44A9FF9E-5715-4BF0-9BE2-525883281420/Documents/regions.cid0.plist


(gdb) po arrr
<__NSArrayI 0x8022b30>(
{
    countryID = "<null>";
    region = "?\U00e2vora";
    regionID = 16;
},
{
    countryID = "<null>";
    region = Vicenza;
    regionID = 14;
},
{
    countryID = "<null>";
    region = Wales;
    regionID = 23;
}
)

Answer 1

If you read the documentation closely, writeToFile:atomically: expects the array to contain only objects which can be written into a plist file. This is somewhat more restrictive than what's usually allowed in NSArrays. In particular, the value [NSNull null] is not acceptable. Only objects of type NSArray, NSDictionary, NSData, and NSString are permitted, and any array or dictionary values will be recursively examined by the same criteria.