UIDocument does not allow you to write strings directly to disk

If you are using UIDocument in your app, always remember that UIDocument doesn't allow you to write strings directly to disk.

You need to package the string value in NSData then you can write it to disk. You can do it using the contentsForType:error method.

Below is a sample code, first check that the string is not NULL :

- (id)contentsForType:(NSString *)typeName error:(NSError **) myError{
    if (!self.stringDocument)
        self.stringDocument = @"";

    NSData *nsDataDocument = [self.stringDocument
                           dataUsingEncoding:NSUTF8StringEncoding];
    return nsDataDocument;
}

written by: infinitywebseo