How to get the method of backBarButtonItem of navigationItem?

I have add the navigationItem.backBarButtonItem when turn to the new page like the following code , but I want to add a Timer for change some image before turn back to the first by backBarButtonItem.

    UIViewController *ReconnectView = [[AITReconnectView alloc] initWithNibName:@"AITReconnectView" bundle:nil] ;      
    ReconnectView.edgesForExtendedLayout = UIRectEdgeNone;          
    self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(@"Back", nil) style:UIBarButtonItemStyleBordered target:nil action:nil];               
   [self.navigationController pushViewController:ReconnectView animated:YES];

For example : When I click the backBarButtonItem , it will run the Timer for 3 second. And then turn back to the first view.

I have search for some information , but it only overwrite the new method for backBarButtonItem.

How to add a Timer in method of backBarButtonItem but retain the original method of backBarButtonItem ?

Thanks in advance.

There are two ways:

1. Create your own back button (similar like native) and selector method and assign it to button:

   UIBarButtonItem *addButton = [[[UIBarButtonItem alloc] initWithTitle:@"BackToVcA"
                                                                  style:UIBarButtonItemStyleBordered
                                                                 target:self
                                                                 action:@selector(addAction:)] autorelease];
   
   self.navigationItem.rightBarButtonItem = addButton;
   

2. Use UIViewController life cycle method, viewWillDisappear or viewDidDisappear.

Hope this is what you're looking for.