Activity recognition using core motion

Here's some sample code using a Data Model and SwiftUI

**** The Data Model

import Foundation

import CoreMotion

class DataModel : ObservableObject {

    var activityManager : CMMotionActivityManager?

    @Published var activities = [CMMotionActivity] () // (remove the space before the ()

    init() {

        if !CMMotionActivityManager.isActivityAvailable() {

            print("Activity Monitoring not available")

            return

        }

        activityManager = CMMotionActivityManager()

        if activityManager == nil {  // check just to be sure initialised OK

            print("Unable to initialise Activity Manager")

            return

        }

        activityManager!.startActivityUpdates(to: OperationQueue.main) { (motion) in

            guard let newMotion = motion else { return }

            self.activities.append(newMotion)

        }

    }

}

extension CMMotionActivity {

    func activityString() -> String {

        // returns a compound string of activities e.g. Stationary Automotive

        var output = ""

        if stationary { output = output + "Stationary "}

        if walking { output = output + "Walking "}

        if running { output = output + "Running "}

        if automotive { output = output + "Automotive "}

        if cycling { output = output + "Cycling "}

        if unknown { output = output + "Unknown "}

        return output

    }

}

**** The Main App (if generated in Xcode 12+)

import SwiftUI

@main

struct Activity_TrackerApp: App {

    @StateObject var dataModel = DataModel()

    var body: some Scene {

        WindowGroup {

            ContentView()

                .environmentObject(dataModel)

        }

    }

}

**** The Content View

import SwiftUI

struct ContentView: View {

    @EnvironmentObject var dataModel: DataModel

    var body: some View {

        ScrollView {

            ForEach(dataModel.activities, id:\.startDate) {activity in

                HStack{

                    Text(activity.startDate, style: .date)

                    Text(activity.startDate, style: .time)

                    Text(activity.activityString())

                }

            }

        }

    }

}

You must also add a Plist key for Privacy - Motion Usage Description and say why you're recording activity.

This is a very rough UI, but it should get you started. You'll also need (??) to turn off monitoring at some point and deal with entering and exiting background mode.

Good luck and regards, Michaela