Sample code for determine the path of a resource file. Initially the resource file is shipped with the application bundle, but if user modifies it, it is saved to document folder

ResourcePathLocator.mm

// TODO: pathForResource:@"Party.xml" ofType:nil should work. 
// If so, then we can extract Party.xml as parameter. Better, we can add a path parameters, so that the file is stored
// to <DocumentPath>/data/<someFile>
//
+ (NSString *)dataFilePath:(BOOL)forSave {
 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, 
        NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *documentsPath = [documentsDirectory
        stringByAppendingPathComponent:@"Party.xml"];
    if (forSave || 
        [[NSFileManager defaultManager] fileExistsAtPath:documentsPath]) {
        return documentsPath;
    } else {
        return [[NSBundle mainBundle] pathForResource:@"Party" ofType:@"xml"];
    }
 
}