After phone restart 'unfortunately app has stopped' error - xamarin.forms

Question

I get "unfortunately app has stopped" error after phone restart. My Phone is Oreo 8 but another phone with Nougat 7.1.1 also having the same error after phone restart. I use James Montemagnos' MyStepCounter bound services codes from GitHub with some changes in VS 2017 (Xamarin Cross-Platform App). The app is working fine if once started after phone restart with this error, else it is not counting steps and not working on the background. If I check the app in Phone Settings-General-Battery-Power saving exclusions then it works with no problems after phone restart and it is counting steps on the background without starting the app on Oreo phone. But there are no settings for battery power saving exclusions on the other phone
BootReceiver.cs
[BroadcastReceiver(Enabled = true, Exported = true, DirectBootAware = true)]
[IntentFilter(new string[] { Intent.ActionBootCompleted, Intent.ActionLockedBootCompleted, "android.intent.action.QUICKBOOT_POWERON", "com.htc.intent.action.QUICKBOOT_POWERON" })]
public class BootReceiver : BroadcastReceiver
{
public override void OnReceive(Context context, Intent intent)
{
var stepServiceIntent = new Intent(context, typeof(StepService));
context.StartService(stepServiceIntent);
}
}
StepServiceBinder.cs
public class StepServiceBinder : Binder
{
StepService stepService;
public StepServiceBinder(StepService service)
{
this.stepService = service;
}
public StepService StepService
{
get { return stepService; }
}
}
StepServiceConnection.cs
public class StepServiceConnection : Java.Lang.Object, IServiceConnection
{
MainActivity activity;
public StepServiceConnection(MainActivity activity)
{
this.activity = activity;
}
public void OnServiceConnected(ComponentName name, IBinder service)
{
var serviceBinder = service as StepServiceBinder;
if (serviceBinder != null)
{
activity.Binder = serviceBinder;
activity.IsBound = true;
}
}
public void OnServiceDisconnected(ComponentName name)
{
activity.IsBound = false;
}
}
StepService.cs
public class StepServiceConnection : Java.Lang.Object, IServiceConnection
{
MainActivity activity;
public StepServiceConnection(MainActivity activity)
{
this.activity = activity;
}
public void OnServiceConnected(ComponentName name, IBinder service)
{
var serviceBinder = service as StepServiceBinder;
if (serviceBinder != null)
{
activity.Binder = serviceBinder;
activity.IsBound = true;
}
}
public void OnServiceDisconnected(ComponentName name)
{
activity.IsBound = false;
}
}
StepService.cs
[Service(Enabled = true)]
[IntentFilter(new String[] { "com.PedometerApp.StepService" })]
public class StepService : Service, ISensorEventListener, INotifyPropertyChanged
{
private SensorManager sManager;
private bool isRunning;
private long stepsToday = 0;
public bool WarningState
{
get;
set;
}
public long StepsToday
{
get { return stepsToday; }
set
{
if (stepsToday == value)
return;
stepsToday = value;
OnPropertyChanged("StepsToday");
Settings.CurrentDaySteps = value;
MessagingCenter.Send<object, long>(this, "Steps", Settings.CurrentDaySteps);
}
}
public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
{
var alarmManager = ((AlarmManager)ApplicationContext.GetSystemService(AlarmService));
var intent2 = new Intent(this, typeof(StepService));
intent2.PutExtra("warning", WarningState);
var stepIntent = PendingIntent.GetService(ApplicationContext, 200, intent2, PendingIntentFlags.UpdateCurrent);
alarmManager.Set(AlarmType.Rtc, Java.Lang.JavaSystem
.CurrentTimeMillis() + 1000 * 60 * 60, stepIntent);
var warning = false;
if (intent != null)
warning = intent.GetBooleanExtra("warning", false);
Startup();
return StartCommandResult.Sticky;
}
public override void OnTaskRemoved(Intent rootIntent)
{
base.OnTaskRemoved(rootIntent);
UnregisterListeners();
var intent = new Intent(this, typeof(StepService));
intent.PutExtra("warning", WarningState);
((AlarmManager)GetSystemService(AlarmService)).Set(AlarmType.Rtc, Java.Lang.JavaSystem
.CurrentTimeMillis() + 500,
PendingIntent.GetService(this, 201, intent, 0));
}
private void Startup(bool warning = false)
{
CrunchDates(true);
if (!isRunning)
{
RegisterListeners();
WarningState = warning;
}
isRunning = true;
}
public override void OnDestroy()
{
base.OnDestroy();
UnregisterListeners();
isRunning = false;
CrunchDates();
}
void RegisterListeners()
{
sManager = GetSystemService(SensorService) as SensorManager;
sManager.RegisterListener(this, sManager.GetDefaultSensor(SensorType.StepCounter), SensorDelay.Ui);
}
void UnregisterListeners()
{
if (!isRunning)
return;
try
{
var sensorManager = (SensorManager)GetSystemService(Context.SensorService);
sensorManager.UnregisterListener(this);
isRunning = false;
}
catch (Exception ex)
{
}
}
StepServiceBinder binder;
public override Android.OS.IBinder OnBind(Android.Content.Intent intent)
{
binder = new StepServiceBinder(this);
return binder;
}
public void OnAccuracyChanged(Sensor sensor, SensorStatus accuracy)
{
//do nothing here
}
public void AddSteps(long count)
{
if (lastSteps == 0)
{
lastSteps = count;
}
newSteps = count - lastSteps;
if (newSteps < 0)
newSteps = 1;
else if (newSteps > 100)
newSteps = 1;
lastSteps = count;
CrunchDates();
Settings.TotalSteps += newSteps;
StepsToday = Settings.TotalSteps - Settings.StepsBeforeToday;
}
long newSteps = 0;
long lastSteps = 0;
public void OnSensorChanged(SensorEvent e)
{
if (lastSteps < 0)
lastSteps = 0;
var count = (long)e.Values[0];
WarningState = false;
AddSteps(count);
}
private void CrunchDates(bool startup = false)
{
if (!Utils.IsSameDay)
{
var yesterday = Settings.CurrentDay;
var dayEntry = StepEntryManager.GetStepEntry(yesterday);
if (dayEntry == null || dayEntry.Date.DayOfYear != yesterday.DayOfYear)
{
dayEntry = new StepEntry();
}
dayEntry.Date = yesterday;
dayEntry.Steps = Settings.CurrentDaySteps;
Settings.CurrentDay = DateTime.Today;
Settings.CurrentDaySteps = 0;
Settings.StepsBeforeToday = Settings.TotalSteps;
StepsToday = 0;
try
{
StepEntryManager.SaveStepEntry(dayEntry);
}
catch (Exception ex)
{
Console.WriteLine("Error {0}", ex.Message);
}
}
else if (startup)
{
StepsToday = Settings.TotalSteps - Settings.StepsBeforeToday;
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string name)
{
if (PropertyChanged == null)
return;
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}