Unable to force UIViewController orientation

问题

I have a portrait application with one landscape ViewController.

I've been digging a lot on how to force the orientation to landscape when the app is locked to portrait and I tried a lot of solutions presented here and not only but without any luck so far.

So far I managed to autorotate the VC I need in landscape but since the orientation is not locked, all other VCs will also rotate.

override func viewDidAppear(animated: Bool)
{
    let value = UIInterfaceOrientation.LandscapeRight.rawValue
    UIDevice.currentDevice().setValue(value, forKey: "orientation")
}

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

After some more digging I ended up with this after finding a sample project but while it works in that project, it doesn't seem to work for me.

This is in AppDelegate

func application(application: UIApplication, supportedInterfaceOrientationsForWindow window: UIWindow?) -> UIInterfaceOrientationMask {

    if self.window?.rootViewController?.presentedViewController is ConclusionReferencesVC {

        let conclusionReferencesVC = self.window!.rootViewController!.presentedViewController as! ConclusionReferencesVC

        if conclusionReferencesVC.isPresented
        {
            return UIInterfaceOrientationMask.LandscapeRight;
        }
        else
        {
            return UIInterfaceOrientationMask.Portrait;
        }
    }
    else
    {
        return UIInterfaceOrientationMask.Portrait;
    }
}

This is in the VC I want to have in landscape:

var isPresented = true

@IBAction
func dismiss()
{
    isPresented = false
    self.presentingViewController!.dismissViewControllerAnimated(true, completion: nil);
}

For some reason, the supportedInterfaceOrientationsForWindow method does not validate the initial condition.

I also tried these among others but no luck:

How to lock orientation of one view controller to portrait mode only in Swift

supportedInterfaceOrientationsForWindow in Swift 2.0

Any ideas? It seems I'm missing something but I can't figure it out what.

回答1:

try this for force to LandscapeRight mode only

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

        if(self.supportedInterfaceOrientations() == UIInterfaceOrientationMask.LandscapeRight && UIDevice.currentDevice().orientation != UIDeviceOrientation.LandscapeRight)
        {
            let value = UIInterfaceOrientation.LandscapeRight.rawValue
            UIDevice.currentDevice().setValue(value, forKey: "orientation")
        }

    }

and then use a category like this

    import UIKit

extension UINavigationController{

    override public func shouldAutorotate() -> Bool
    {
    return (self.viewControllers.last?.shouldAutorotate())!
    }

    override public func supportedInterfaceOrientations() ->UIInterfaceOrientationMask
    {
    return (self.viewControllers.last?.supportedInterfaceOrientations())!;
    }

    override public func preferredInterfaceOrientationForPresentation()-> UIInterfaceOrientation
    {
    return (self.viewControllers.last?.preferredInterfaceOrientationForPresentation())!;
    }

}

EDITED

If you are not using navigation controller use this

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

        if(self.supportedInterfaceOrientations() == UIInterfaceOrientationMask.LandscapeRight && UIDevice.currentDevice().orientation != UIDeviceOrientation.LandscapeRight)
        {
            let value = UIInterfaceOrientation.LandscapeRight.rawValue
            UIDevice.currentDevice().setValue(value, forKey: "orientation")
        }

    }

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

I hope this helps you

回答2:

As an update to Reinier Melian's post, here is the UINavigationController extension in Swift 3:

import UIKit

extension UINavigationController {
    override open var shouldAutorotate: Bool {
        return (self.viewControllers.last?.shouldAutorotate)!
    }

    override open var supportedInterfaceOrientations: UIInterfaceOrientationMask {
        return (self.viewControllers.last?.supportedInterfaceOrientations)!
    }

    override open var preferredInterfaceOrientationForPresentation: UIInterfaceOrientation {
        return (self.viewControllers.last?.preferredInterfaceOrientationForPresentation)!
    }
}

Unfortunately, this code crashes if you call a UIImagePickerController, as that is contained within a UINavigationController whose last view controller is nil.

回答3:

probably I´m crazy ;-), but why don´t u use this?

来源：https://stackoverflow.com/questions/38308919/unable-to-force-uiviewcontroller-orientation