Retrieve Device Motion data only once - Core Motion

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Created Nov ’20

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I'm using Core Motion to see if the phone is facing upwards or downwards, and I only need to retrieve the data once. Here is some of my code:

Code Block swiftlet manager = CMMotionManager()
manager.showsDeviceMovementDisplay = true
// "Pull data" - since I only need it once
manager.deviceMotionUpdateInterval = 1.0 / 60.0
manager.startDeviceMotionUpdates(using: .xMagneticNorthZVertical)
// Repeats set to false since I only need it once - but same problem even when set to true
self.timer = Timer(fire: Date(), interval: 1.0 / 60.0, repeats: false) { _ in
    print("Timer started")
    if let motionData = manager.deviceMotion?.gravity.z {
        print("Successfully unwrapped")
        if 0.7...1 ~= motionData { // Facing downwards
            print("Facing downwards")
            position = .downwards(motionData)
        } else if -1...(-0.7) ~= motionData { // Facing upwards
            print("Facing upwards")
            position = .upwards(motionData)
        } else {
            print("Position uknown")
            position = .unknown
        }
    }
}
RunLoop.current.add(self.timer!, forMode: RunLoop.Mode.default)

However, I never reach "Successfully unwrapped". From my attempts to debug, I found that manager.isDeviceMotionActive is never set to true, even though I called startDeviceMotionUpdates(using: .xMagneticNorthZVertical). Why could that be?

Answered by theepicapple in 648924022

It seems like Paul from Hacking with Swift has come once again to save the day - just found his article on how to detect whether the device is facing upwards or downwards through a notification!
(can't post the link, Apple, or at least the forum text editor, doesn't seem to like it)

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theepicapple OP

Nov ’20

Accepted Answer

It seems like Paul from Hacking with Swift has come once again to save the day - just found his article on how to detect whether the device is facing upwards or downwards through a notification!
(can't post the link, Apple, or at least the forum text editor, doesn't seem to like it)

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