为什么使用 UINavigationController 时不能强制横向？

我发现很多问题强制 UIViewController 默认为横向：如何在 iOS 6 中强制 UIViewController 为纵向 https://stackoverflow.com/questions/12520030/how-to-force-a-uiviewcontroller-to-portait-orientation-in-ios-6并尝试这个：

- (BOOL)shouldAutorotate
{
    return YES;
}

-(NSUInteger)supportedInterfaceOrientations

{
    return UIInterfaceOrientationMaskLandscape;
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return UIInterfaceOrientationLandscapeLeft;
}

但是当我在 UINavigationController 中使用 UIViewController 时，我无法强制横向。请帮忙！

*工作不好

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];

    UINavigationController *navControl = [[UINavigationController alloc] initWithRootViewController:self.viewController];
    [navControl setNavigationBarHidden:YES];
    self.window.rootViewController = navControl;

    [self.window makeKeyAndVisible];
    return YES;
}

*工作正常：

self.window.rootViewController = self.viewController;

最好的方法是创建扩展 UINavigationController 并在扩展类中编写方向函数。

类别声明：

@interface MyNavigationControllerViewController : UINavigationController

@property(nonatomic, assign) UIInterfaceOrientation orientation;
@property(nonatomic, assign) NSUInteger supportedInterfaceOrientatoin;
@end

MyNavigationController 的实现

@implementation MyNavigationController

@synthesize supportedInterfaceOrientatoin = _supportedInterfaceOrientatoin;

@synthesize orientation = _orientation;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        _supportedInterfaceOrientatoin = UIInterfaceOrientationMaskLandscape;
        _orientation = UIInterfaceOrientationLandscapeLeft;
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (BOOL)shouldAutorotate
{
    return YES;
}

-(NSUInteger)supportedInterfaceOrientations

{
    return _supportedInterfaceOrientatoin;
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return self.orientation;
}

@end

并使用您的扩展（例如 MyNavigationController）作为 rootviewcontroller 的导航控制器。

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) ViewController *viewController;
@property (strong, nonatomic) MyNavigationControllerViewController *myNavController;

- (void) reloadAppDelegateRootViewControllerLandscape;
- (void) reloadAppDelegateRootViewController;
@end

因此，您的应用程序委托 didfinishlounchingwithoptions 代码将如下所示。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];

    self.myNavController = [[MyNavigationController alloc] initWithRootViewController:self.viewController];
    [self.myNavController setNavigationBarHidden:YES];
    self.window.rootViewController = self.myNavController;

    [self.window makeKeyAndVisible];
    return YES;
}

可以为具有相同导航控制器的两个不同视图提供不同方向的唯一方法是重新加载导航控制器本身。所以如果你添加两个方法

- (void) reloadAppDelegateRootViewController{
    [[[UIApplication sharedApplication].delegate window] setRootViewController:nil];
    [(MyNavigationControllerViewController *)self.myNavController setOrientation:UIInterfaceOrientationPortrait];
    [(MyNavigationControllerViewController *)self.myNavController setSupportedInterfaceOrientatoin:UIInterfaceOrientationMaskAll];
    [[[UIApplication sharedApplication].delegate window] setRootViewController:self.myNavController];
}

- (void) reloadAppDelegateRootViewControllerLandscape{
    [[[UIApplication sharedApplication].delegate window] setRootViewController:nil];
    [(MyNavigationControllerViewController *)self.myNavController setOrientation:UIInterfaceOrientationLandscapeLeft];
    [(MyNavigationControllerViewController *)self.myNavController setSupportedInterfaceOrientatoin:UIInterfaceOrientationMaskLandscape];
    [[[UIApplication sharedApplication].delegate window] setRootViewController:self.myNavController];
}

并在推送和弹出视图后调用这些函数。

注意：-我不知道这是好方法还是坏方法。