Navigation bar button item

navbar-bar-button

/* create a bar button item */
UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithTitle:@"button" style:UIBarButtonItemStylePlain target:self action:@selector(barButtonDidTap:)];
self.navigationItem.rightBarButtonItem = item;

/*
 * call back when bar button did tap
 */
- (void)barButtonDidTap:(id)sender
{
    //do something
}