iOS. How to enable and disable rotation on each UIViewController?

You simply have to implement shouldAutorotate and supportedInterfaceOrientations into your UIViewController. Take a look at this documentation. For example:

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

You can also specify which orientations are available. Here is an example with only portraits orientations:

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

Edit: If you want to support different orientation regarding a flag, you just have to do something like this:

override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
    if myFlag {
        return .Landscape
    } else {
        return .All
    }
}

(If myFlag is true, it will allow Landscape orientation. Otherwise, it will allow all orientations).

swift 4

override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
    get {
        return .portrait

    }
}

In swift 5, as from previous, if you want to allow (avoid others) a particular UIViewController to rotate in a certain orientation you have to override "supportedInterfaceOrientations" inside your UIViewController class like so:

class MyViewController:UIViewController {
    override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
        return .portrait
    }
}

Here there are the possible options:

public struct UIInterfaceOrientationMask : OptionSet {

    public init(rawValue: UInt)

    
    public static var portrait: UIInterfaceOrientationMask { get }

    public static var landscapeLeft: UIInterfaceOrientationMask { get }

    public static var landscapeRight: UIInterfaceOrientationMask { get }

    public static var portraitUpsideDown: UIInterfaceOrientationMask { get }

    public static var landscape: UIInterfaceOrientationMask { get }

    public static var all: UIInterfaceOrientationMask { get }

    public static var allButUpsideDown: UIInterfaceOrientationMask { get }
}

Extended

If you want to be able to distinguish between iPad or iPhone you could use UIUserInterfaceIdiom:

override var supportedInterfaceOrientations: UIInterfaceOrientationMask{
    get{
        return UIDevice.current.userInterfaceIdiom == .phone ? [.portrait, . portraitUpsideDown]:.all //OBS -> You can also return an array
    }
}

where:

public enum UIUserInterfaceIdiom : Int {

    
    case unspecified

    @available(iOS 3.2, *)
    case phone // iPhone and iPod touch style UI

    @available(iOS 3.2, *)
    case pad // iPad style UI

    @available(iOS 9.0, *)
    case tv // Apple TV style UI

    @available(iOS 9.0, *)
    case carPlay // CarPlay style UI
}

I have the answer. On AppDelegate, if you rotate device, push viewcontroller, etc. This function always call

Update for swift 3/4

func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask
{
    return self.restrictRotation
}

self.restrictRotation is a custom parameter.

How to use:

In Appdelegate:

 var restrictRotation:UIInterfaceOrientationMask = .portrait

In ViewController:

When method ViewDidLoad or viewWillAppear is called. We will change like this:

(UIApplication.shared.delegate as! AppDelegate).restrictRotation = .all 

and then this method on AppDelegate will be called.

func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask