如何使用 Xamarin 应用程序开发自动注销

我必须在 App.xaml.cs 上添加功能才能使其正常工作。我在 OnStart 上添加了功能，但现在它会间歇性地一次又一次地将我从应用程序中注销。根据下面的代码，我需要做什么才能让它停止这样做。或者我的代码有问题。这是我最新的代码：

  namespace MyApp
  {
   public partial class App : Application
  {
    DateTime _sessionStart;

    public App()
    {
       InitializeComponent();

        DatabaseManager = new DatabaseManager(new DatabaseService());

        HttpManager = new HttpManager(new HTTPService());

        MainPage = new NavigationPage(new LoginPage());
    }

    protected override void OnStart()
    {
        // Handle when your app starts
        _sessionStart = DateTime.Now;

        Device.StartTimer(TimeSpan.FromSeconds(60), () =>
        {
            // Check if 24 hours has elapsed
            if (DateTime.Now > _sessionStart.AddHours(24))
            {
                //logout
                 MainPage = new NavigationPage(new LoginPage());
            }

            return true; // True = Repeat again, False = Stop the timer
        });


    }

    protected override void OnSleep()
    {
        // Handle when your app sleeps
    }

    protected override void OnResume()
    {
        // Handle when your app resumes
    }
}

尝试通过在 Main 上注册自定义应用程序来跟踪空闲时间（应用程序中没有触摸的时间）。请参阅下面的示例

Set TimeoutInSeconds值到您想要的间隔（例如 24 小时）

public class Application
{
    // This is the main entry point of the application.
    static void Main (string[] args)
    {
        UIApplication.Main (args, "MYCUSTOMAPP", "AppDelegate");
    }
}

[Register ("MYCUSTOMAPP")]
public class MYCUSTOMAPP : UIApplication
{ 
    const int TimeoutInSeconds = 1800; // 30 minutes
    NSTimer idleTimer;

    public override void SendEvent (UIEvent uievent)
    {
        base.SendEvent (uievent);

        if (idleTimer == null)
            ResetTimer ();
        var allTouches = uievent.AllTouches;
        if (allTouches != null && allTouches.Count > 0 && ((UITouch)allTouches.First ()).Phase == UITouchPhase.Began)
            ResetTimer ();
    }

    void ResetTimer ()
    {
        if (idleTimer != null)
            idleTimer.Invalidate ();

        idleTimer = NSTimer.CreateScheduledTimer (new TimeSpan (0, 0, TimeoutInSeconds), (t) => TimerExceeded());

    }

    void  TimerExceeded ()
    {
        NSNotificationCenter.DefaultCenter.PostNotificationName ("TimeoutNotification", null);
    }
}

将观察者添加到您的视图控制器以将其注销

    public override void ViewDidLoad()
    {
        base.ViewDidLoad();
        NSNotificationCenter.DefaultCenter.AddObserver(new NSString("TimeoutNotification"), handleInactivityNotification);
    }

    public void handleInactivityNotification(NSNotification notification)
    {
        //Return to login page (Root view controller)
        this.NavigationController.PopToRootViewController(true);
    }