applicationDidEnterBackground - How to save my user data

A novice's question.

I have one NotePageAppDelegate and one NotePageViewController. Simple. In my ViewController, I have defined a method to save the user data. It works perfectly if I click a button in my app which calls the method saveToDisk which is defined in my ViewController.

    -(IBAction) saveToDisk
{ // saves the file to the disk
}

This works perfectly if I click my button. However, 开发者_高级运维if I close the app (i.e. in the Simulator clicking the Home Button), I would like to automatically save the page. I thought this is rather straight forward, so I put this in my AppDelegate:

- (void)applicationDidEnterBackground:(UIApplication *)application {

    NotePageViewController* controller = [NotePageViewController alloc];

    [controller saveToDisk]; 

    [controller release];

}

However, this has no effect whatsoever. Have I forgotten to define something else? Or should this theoretically do the job if I press the Home Button in the Simulator?

Thanks for your help!

I'm surprised that doesn't crash, since you're calling a method on an uninitialized instance.

You have the right idea, but you should be calling saveToDisk on an instance of the controller that already exists, not creating a new one that probably has no user modifications.