程序化地改变方向不能正常工作

My whole application is in portrait mode. I just want to use one view controller in landscape mode (left).

我的整个应用程序都处于纵向模式。我只想在横向模式(左)中使用一个视图控制器。

func application(application: UIApplication, supportedInterfaceOrientationsForWindow window: UIWindow?) -> UIInterfaceOrientationMask 
{
    if let _navigationController = window?.rootViewController as? UINavigationController {

        if _navigationController.topViewController is FullScreenPlayerVC {

            return UIInterfaceOrientationMask.LandscapeLeft
        }
    }

    return UIInterfaceOrientationMask.Portrait
}

This is my controller A

这是我的控制器A

override func shouldAutorotate() -> Bool
{
    return true
}

override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask
{
    return UIInterfaceOrientationMask.Portrait
}

Now i push Controller B. This is my controller B

现在我推控制器B，这是控制器B

override func viewDidAppear(animated: Bool)
{
    super.viewDidAppear(animated)

    let value = UIInterfaceOrientation.LandscapeLeft.rawValue
    UIDevice.currentDevice().setValue(value, forKey: "orientation")
 }

override func shouldAutorotate() -> Bool
{
    return true
}

override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask
{
    return UIInterfaceOrientationMask.Landscape
}

It works as per my requirement when i push controller B while holding my device in portrait mode but if i am holding my phone in landscape left already.

按我的要求，当我用竖屏模式按住设备时按下控制器B，但如果我用横屏模式按住手机的话，它就会工作。

It does not perform desired action. Searched a lot about it but not able to find the solution yet.

它不执行期望的动作。搜索了很多，但是还没有找到解决方案。

I have tried many solutions but nothings working fine.

我已经尝试了很多解决方案，但没有什么是好的。

1 个解决方案

#1

This is a generic solution for your problem and others related.

这是针对您的问题和其他相关问题的通用解决方案。

1. Create auxiliar class UIHelper and put on the following methods:

1。创建辅助类UIHelper，并使用以下方法:

    /**This method returns top view controller in application  */
    class func topViewController() -> UIViewController?
    {
        let helper = UIHelper()
        return helper.topViewControllerWithRootViewController(rootViewController: UIApplication.shared.keyWindow?.rootViewController)
    }

    /**This is a recursive method to select the top View Controller in a app, either with TabBarController or not */
    private func topViewControllerWithRootViewController(rootViewController:UIViewController?) -> UIViewController?
    {
        if(rootViewController != nil)
        {
            // UITabBarController
            if let tabBarController = rootViewController as? UITabBarController,
                let selectedViewController = tabBarController.selectedViewController {
                return self.topViewControllerWithRootViewController(rootViewController: selectedViewController)
            }

            // UINavigationController
            if let navigationController = rootViewController as? UINavigationController ,let visibleViewController = navigationController.visibleViewController {
                return self.topViewControllerWithRootViewController(rootViewController: visibleViewController)
            }

            if ((rootViewController!.presentedViewController) != nil) {
                let presentedViewController = rootViewController!.presentedViewController;
                return self.topViewControllerWithRootViewController(rootViewController: presentedViewController!);
            }else
            {
                return rootViewController
            }
        }

        return nil
    }

2. Create a Protocol with your desire behavior, for your specific case will be landscape.

2。创建一个协议与你的愿望行为，为你的具体情况将是风景。

protocol orientationIsOnlyLandscape {}

协议orientationIsOnlyLandscape { }

Nota: If you want, add it in the top of UIHelper Class.

如果你想的话，把它添加到UIHelper类的顶部。

3. Extend your View Controller

3所示。扩展你的视图控制器

In your case:

在你的例子:

class B_ViewController: UIViewController,orientationIsOnlyLandscape {

   ....

}

4. In app delegate class add this method:

4所示。在app委托类中添加该方法:

 func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
        let presentedViewController = UIHelper.topViewController()
        if presentedViewController is orientationIsOnlyLandscape {
            return .landscape
        }
        return .portrait
    }

Final Notes:

最后指出:

If you that more class are in landscape mode, just extend that protocol.
如果您认为更多的类处于横向模式，那么就扩展该协议。
If you want others behaviors from view controllers, create other protocols and follow the same structure.
如果您希望视图控制器中的其他行为，请创建其他协议并遵循相同的结构。
This example solves the problem with orientations changes after push view controllers
这个例子解决了在推视图控制器之后朝向改变的问题

#1