Sort TableView cells with AlertView in XCode 4
===

I've added a "Sort" button to the NavigationBar to sort the TableView. The TableView is build this way:

    - (void)viewDidLoad
    {
        [super viewDidLoad];
    
        NSString *myfile = [[NSBundle mainBundle]
                        pathForResource:@"Object" ofType:@"plist"];
    
        sortedObjectes = [[NSMutableArray alloc]initWithContentsOfFile:myfile];
    
        NSSortDescriptor * sortDesc = [[NSSortDescriptor alloc] initWithKey:@"Name" ascending:YES];
        [sortedObjects sortUsingDescriptors:[NSArray arrayWithObject:sortDesc]];
        [super viewDidLoad];
     }

(Then the values for the keys are extracted in CellForRowAtIndexPath, using prototype custom cell.)

This is the Action: 

    - (IBAction)SortButton:(id)sender;

    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sort by" message:@"" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Name", @"Country", @"Popularity", nil];                                                                                                                                   
    [alert show];
    [alert release];
    }

And this is the delegate method to catch the button click:

    - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
    {
	    if (buttonIndex == 0)
	    {
        //Sort by name
	    }
	    else if (buttonIndex == 1)
	    {
        //Sort by country
	    }
        else if (buttonIndex == 2)
        {
        //Sort by popularity
	    }
    }

How do I implement the SortDescriptor method in ClickedButtonAtIndex, and update the TableView? 

I want the tableview sorted by popularity by default.