Xamarin forms: Check if user inactive after some time log out app

Question

Hi I am trying to build an application in xamarin forms using PCL. I am trying to logout user from my app if the app is idle more than 10minute or more. I tried it by events

Answer 1

I was able to use the Device.StartTimer in Xamarin Forms to create an expiration. For my app the user switched screens fairly often so I would cause inactivity to be reset between screen transitions. It was a little less obnoxious then tying the method to each button press and screen tap. The class that houses the logic looks something like this:

public class InactivityService
{  
    public ActivityMonitorService( )
    { 
    }

    public DateTime LastClick { get; private set; }
    public TimeSpan MaxLength { get; private set; }

    public void Start(TimeSpan maxDuration, Action expirationCallback = null)
    {
        MaxLength = maxDuration;
        Notify();
        _expirationCallBack = expirationCallback;
        ResetTimer();
    }

    public void Notify()
    { 
        LastClick = DateTime.Now;
    }

    public void Stop()
    {
    }

    public TimeSpan TimeSinceLastNotification()
    {
        var now = DateTime.Now;
        var timeSinceLastClick = now - LastClick;
        return timeSinceLastClick;
    }

    public TimeSpan GetNewTimerSpan()
    {
        var newDuration = MaxLength - TimeSinceLastNotification();
        return newDuration;
    }

    public bool IsExpired(DateTime time)
    {
        return time - LastClick > MaxLength;
    }

    private bool CallBack()
    {
        if (IsExpired(DateTime.Now))
        {
            Expire();
        }
        else
        {
            ResetTimer();
        }

        return false;
    }

    public async void Expire()
    {
        if (_expirationCallBack != null)
            _expirationCallBack.Invoke();
        Stop(); 
        //Notify user of logout
        //Do logout navigation
    }

    private void ResetTimer()
    {
        Device.StartTimer(GetNewTimerSpan(), CallBack);
    }
}