How to check whether an iPhone or iPad is upside down or face up

Swift version: 5.1

Paul Hudson    @twostraws    November 28th 2019

If your app needs to know the orientation of the user’s device – face up or face down – it takes only four steps to implement.

First, write a method that can be called when the device orientation changes:

@objc func orientationChanged() {

}

That needs to be marked @objc because it’s going to be called by the system whenever the accelerometer signals the orientation has changed. So, step two is to request those changes be sent to the new method:

NotificationCenter.default.addObserver(self, selector: #selector(orientationChanged), name: UIDevice.orientationDidChangeNotification, object: nil)

Third, ask the system to start checking for orientation changes:

UIDevice.current.beginGeneratingDeviceOrientationNotifications()

You shouldn’t leave that on all the time unless you need it; you should call endGeneratingDeviceOrientationNotifications() when you’re done with the data.

Finally, you can read the orientation property of the current UIDevice to see what the orientation currently is. This property doesn’t work correctly unless you already asked UIKit to begin generating device orientation notifications, which is why the above steps were required:

if UIDevice.current.orientation == .faceDown {
    // it's face down
}

You probably want that inside orientationChanged() so that it reads values as they change.

Sponsor Hacking with Swift and reach the world's largest Swift community!

Available from iOS 2.0

Similar solutions…

• How to do conditional test tear down using addTeardownBlock()
• How to read the battery level of an iPhone or iPad
• How to run code when your app is terminated
• How to scale a view up or down
• How to detect keyboard input using pressesBegan() and pressesEnded()

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.