iPhone 旋转后 UINavigationBar 消失

Question

我有一个应用程序在 didFinishLaunchingWithOptions 方法中设置 UINavigationController，如下所示：

 main_iPhone *mainiPhone = [[main_iPhone alloc] initWithNibName:@"main_iPhone" bundle:nil];
mainiPhone.navigationItem.title = @"TitleHere";

UIBarButtonItem *botaoSobre = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:mainiPhone action:@selector(goToAboutView)];
mainiPhone.navigationItem.rightBarButtonItem = botaoSobre;

navController = [[UINavigationController alloc] initWithRootViewController:mainiPhone];
navController.navigationBar.tintColor = [UIColor orangeColor];
navController.navigationBar.translucent = NO;

[self.window addSubview:navController.view];
[self.window makeKeyAndVisible];
return YES;

当我运行该应用程序时，导航栏仅在纵向模式下正确显示。但是，当我旋转设备以横向显示时，导航栏就会消失。当我旋转回纵向方式时，我也没有恢复导航栏。

PS：我的 mainiPhone.xib 文件有 2 个视图（一个在纵向模式下，一个在横向模式下）。我像这样切换 mainiPhone.m 内的视图：

- (void)willAnimateRotationToInterfaceOrientation:

(UIInterfaceOrientation) interfaceOrientation 持续时间： (NSTimeInterval) period {

if (interfaceOrientation == UIInterfaceOrientationPortrait) {
    self.view = self.portrait; 
    self.view.transform = CGAffineTransformIdentity;
    self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(0)); 
    self.view.bounds = CGRectMake(0.0, 0.0, 320.0, 460.0);


} else if (interfaceOrientation == UIInterfaceOrientationLandscapeLeft) {
    self.view = self.landscape; 
    self.view.transform = CGAffineTransformIdentity; 
    self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(-90)); 
    self.view.bounds = CGRectMake(0.0, 0.0, 480.0, 300.0);


} else if (interfaceOrientation ==  UIInterfaceOrientationPortraitUpsideDown) { 
    self.view = self.portrait; 
    self.view.transform = CGAffineTransformIdentity; 
    self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(180)); 
    self.view.bounds = CGRectMake(0.0, 0.0, 320.0, 460.0);


} else if (interfaceOrientation == UIInterfaceOrientationLandscapeRight) { 

    self.view = self.landscape; 
    self.view.transform = CGAffineTransformIdentity; 
    self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(90)); 
    self.view.bounds = CGRectMake(0.0, 0.0, 480.0, 300.0);
}

}

另外，我的 shouldAutorotateToInterfaceOrientation 方法只返回 YES。

我做错了什么？ 预先非常感谢您！