finngaida / MotionProvider

A Combine-based CoreMotion data provider as a Swift Package

MotionProvider

A Combine-based CoreMotion data provider as a Swift Package.

On every update of the device motion data (accelerometer and gyroscope), it provides a struct

struct MotionData {
    var timestamp : Date
    var acc_x : Double // userAcceleration.x
    var acc_y : Double // userAcceleration.y
    var acc_z : Double // userAcceleration.z
    var rot_x : Double // rotationRate.x
    var rot_y : Double // rotationRate.y
    var rot_z : Double // rotationRate.z
}

through a PassthroughSubject<MotionData, Never> called motionWillChange, as well as a published property motion.

If real location data is unavailable on the device (e.g., the Simulator), it provides random fake-motion data scheduled by a timer.

Usage

Starting the Motion Provider

Initialize and start the MotionProvider

let motionProvider = MotionProvider()
motionProvider.start()

Handling the Motion Data

Subscribe to the motionWillChange subject and store the returned Cancellable

cancellableMotion = motionProvider.motionWillChange.sink { md in
    handleMotion(md)
}

The function handleMotion in the sink closure is executed on every MotionData object sent by the MotionProvider.

Also, the MotionProvider is an ObservableObject which has a published property motion that updates the ObservableObject. This dynamic property can directly be accessed in SwiftUI.

Stopping the Motion Provider

Stop the MotionProvider and cancel the subscription

motionProvider.stop()
cancellableMotion?.cancel()