CODEWITHSUNDEEP
iosiphonexamarin
makerofthings7
makerofthings7

Reputation: 61463

How to tell if the iPhone is "face down" or "face up"?

I need to detect which direction the iPhone is facing so I can record from the non obstructed camera (Front or Back) when dropped.

This will be used in emergency situation and the phone is dropped, or placed in such a way that the active camera is recording nothing of value.

What API or technique can I use to determine this?

Upvotes: 6

Views: 2858

Answers (3)

dustinrwh
dustinrwh

Reputation: 926

Here is a simple function I wrote to start tracking orientation changes so that you can know when it is face down or face up (or whatever orientation you're looking for):

func trackOrientationChanges() {
    UIDevice.current.beginGeneratingDeviceOrientationNotifications()
    NotificationCenter.default.addObserver(forName: UIDevice.orientationDidChangeNotification, object: nil, queue: nil, using:  
    { notificiation in
        if UIDevice.current.orientation == .faceDown {
            print("Device is face down")
        } else {
            print("Device is not face down")
        }
    })
}

Written in Swift 4 but the API is available since iOS 2.0+

Upvotes: 6

Jason
Jason

Reputation: 89102

Check the ProximityState property of the UIDevice class. This will tell you if the screen is near an object (the user's face, or flat on the ground).

For newer devices, you can also use CoreMotion. A positive value on the Z-axis should correspond to the phone's screen being facedown.

Upvotes: 2

matt
matt

Reputation: 535118

Use the Core Motion accelerometer. It reports the direction of gravity, which tells you which way the device is facing.

Upvotes: 4

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