How to detect orientation change?

Question

I am using Swift and I want to be able to load a UIViewController when I rotate to landscape, can anyone point me in the right direction?

I Can't find anything online and a little bit confused by the documentation.

Answer 1

If you want to do something AFTER the rotation is complete, you can use the UIViewControllerTransitionCoordinator completion handler like this

public override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    super.viewWillTransition(to: size, with: coordinator)

    // Hook in to the rotation animation completion handler
    coordinator.animate(alongsideTransition: nil) { (_) in
        // Updates to your UI...
        self.tableView.reloadData()
    }
}

Answer 2

override func didRotate(from fromInterfaceOrientation: UIInterfaceOrientation) {
    //swift 3
    getScreenSize()
}


func getScreenSize(){
   let screenWidth = UIScreen.main.bounds.width
   let  screenHeight = UIScreen.main.bounds.height
    print("SCREEN RESOLUTION: \(screenWidth.description) x \(screenHeight.description)")
}

Answer 3

Here is an easy way to detect the device orientation: (Swift 3)

override func willRotate(to toInterfaceOrientation: UIInterfaceOrientation, duration: TimeInterval) {
            handleViewRotaion(orientation: toInterfaceOrientation)
        }

    //MARK: - Rotation controls
    func handleViewRotaion(orientation:UIInterfaceOrientation) -> Void {
        switch orientation {
        case .portrait :
            print("portrait view")
            break
        case .portraitUpsideDown :
            print("portraitUpsideDown view")
            break
        case .landscapeLeft :
            print("landscapeLeft view")
            break
        case .landscapeRight :
            print("landscapeRight view")
            break
        case .unknown :
            break
        }
    }

Answer 4

My approach is similar to what bpedit shows above, but with an iOS 9+ focus. I wanted to change the scope of the FSCalendar when the view rotates.

override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
    super.viewWillTransitionToSize(size, withTransitionCoordinator: coordinator)

    coordinator.animateAlongsideTransition({ (context) in
        if size.height < size.width {
            self.calendar.setScope(.Week, animated: true)
            self.calendar.appearance.cellShape = .Rectangle
        }
        else {
            self.calendar.appearance.cellShape = .Circle
            self.calendar.setScope(.Month, animated: true)

        }

        }, completion: nil)
}

This below worked, but I felt sheepish about it :)

coordinator.animateAlongsideTransition({ (context) in
        if size.height < size.width {
            self.calendar.scope = .Week
            self.calendar.appearance.cellShape = .Rectangle
        }
        }) { (context) in
            if size.height > size.width {
                self.calendar.scope = .Month
                self.calendar.appearance.cellShape = .Circle
            }
    }

Answer 5

Check if rotation had changed with: viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator)

With the coordinator.animateAlongsideTransition(nil) { (UIViewControllerTransitionCoordinatorContext) you can check if the transition is finished.

See code below:

override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {

    super.viewWillTransitionToSize(size, withTransitionCoordinator: coordinator)

    coordinator.animateAlongsideTransition(nil) { (UIViewControllerTransitionCoordinatorContext) in
        // if you want to execute code after transition finished
        print("Transition finished")
    }

    if size.height < size.width {
        // Landscape
        print("Landscape")
    } else {
        // Portrait
        print("Portrait")
    }

}

Answer 6

Here's how I got it working:

In AppDelegate.swift inside the didFinishLaunchingWithOptions function I put:

NotificationCenter.default.addObserver(self, selector: #selector(AppDelegate.rotated), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil)

and then inside the AppDelegate class I put the following function:

func rotated() {
    if UIDeviceOrientationIsLandscape(UIDevice.current.orientation) {
        print("Landscape")
    }

    if UIDeviceOrientationIsPortrait(UIDevice.current.orientation) {
        print("Portrait")
    }

}

Hope this helps anyone else!

Thanks!