导航器自制导航按钮

1。导航器首视图控制器的在delegate中的代码示例：

    ListAdderViewController*   vc;
    vc =[[[ListAdderViewController alloc] init] autorelease];
   
   [self.navController pushViewController:vc animated:NO];
   
    [self.windowaddSubview:self.navController.view];
2导航器的左右按钮代码 
 self.navgationItem.rightBarButtonItem=[[[UIBarBUttonItemalloc]
initWithTitle:@"Options"
style:UIBarButtonItemStyleBordered
target:self
action:@selector(optionsAction) ]Autorelease];
注意：
self.navigationItem.leftBarButtonItem.possibleTitles = [NSSetsetWithObjects:@"Defaults", @"Minimum", nil];
请详细的了解这个过程