Can you access application delegate from within a UITableViewDataSource function?

Question

I'm trying to figure out the SQLite functionality for the iPhone, and I'm having some problems reading my database file from an overridden UITableViewDataSource function. I am storing the database file location in an ivar (as an NSString) in my application delegate, however when I try to access that string from an overridden UITableViewDataSource function, it returns some other object. If I access the string from any of the classes own instance methods, it works fine.

Is there any way to access the application delegate from within overridden UITableViewDataSource functions?

Answer 1

The Application is a singleton which maintains a reference to the app delegate. You can always access your app delegate using:

[UIApplication sharedApplication].delegate

You may need to cast the return to your own app delegate class to get rid of warnings. Even better, write an accessor that returns your upcast app delegate:

#pragma mark access to app delegate etc.
+ (MyAppDelegateClass*) sharedAppDelegate; {
    return (MyAppDelegateClass*)[[UIApplication sharedApplication] delegate];
}

Answer 2

Roger is correct, but I personally find it extremely confusing to mix dot syntax and bracket syntax in the same statement.

If this confuses you as well, the equivalent syntax, using only bracket notation, is:

[[UIApplication sharedApplication] delegate];

and yes, you may need to cast the result to be your application delegate class, rather than the generic UIApplicationDelegate class, or you will get a number of compiler warnings, most likely.