ios-關於添加UINavigationController

關於添加UINavigationController

如果給UIViewController添加作為modal的UINavigationController。

有一個flow,在firstViewController中開始，然後在view中調用secondViewController。

- (IBAction)PressButton:(id)sender {

    SecondViewController *second = [[SecondViewController alloc] init];
    second.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
    UINavigationController *nav = self.navigationController;
    [nav presentViewController:second animated:YES completion:nil];                              
}

在secondViewController 中希望能推進thirdViewController，但是沒有用，我用了下面的方法嘗試：

- (IBAction)pressButton:(id)sender {

   ThirdViewController *tvc = [[ThirdViewController alloc] init];
   UINavigationController *nav = self.navigationController;
   [nav pushViewController:tvc animated:YES];
}

點擊 secondViewController 時完全沒有反應。

請高手指點一下哪裡出錯了，謝謝
我用的：
OSX 10.8.2
Xcode 4.6
iOS 6.1

最佳回答：

將第二個view作為導航控制器的root,同時從所屬的view中調用當前ViewController

- (IBAction)PressButton:(id)sender {
        SecondViewController *second = [[SecondViewController alloc] init];
        second.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
        UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:second];
        [self presentViewController:navigationController animated:YES completion:nil];    
    }