Closing app on no internet

Question

Hi

I am trying to check internet and to show a mesage to user before closing the app. Problem is DisplayAlert does not show before app is closed. How can I make the DisplayAlert show?

Thanks

Regards

    public partial class App: Application {
      public App() {
        InitializeComponent();
        Current.MainPage = new AppShell();
        if (!CheckInternet()) {
          MainThread.BeginInvokeOnMainThread(async () => {
            // This alert is never shown to user before CloeApp() is called and app is closed
            await MainPage.DisplayAlert("No Internet", "Internet connection is required to use this app.", "OK");
          });
          CloseApp();
        } else {
          await Shell.Current.GoToAsync("//LoginPage");
        }
      }
    }

Answer 1

To ensure that the DisplayAlert shows before the app is closed, you need to await the display alert and then close the app afterward. The CloseApp() method should be called after the user has acknowledged the alert.

Here's the modified version of your code:

public partial class App : Application

{

public App()

{

    InitializeComponent();

    Current.MainPage = new AppShell();

    if (!CheckInternet())

    {

        MainThread.BeginInvokeOnMainThread(async () =>

        {

            // Await the DisplayAlert to ensure it shows before closing the app

            await MainPage.DisplayAlert("No Internet", "Internet connection is required to use this app.", "OK");

            CloseApp(); // Close the app after the alert is acknowledged

        });

    }

    else

    {

        MainThread.BeginInvokeOnMainThread(async () =>

        {

            await Shell.Current.GoToAsync("//LoginPage");

        });

    }

}

private bool CheckInternet()

{

    // Your internet checking logic here

    return true; // For demonstration purposes

}

private void CloseApp()

{

    // Logic to close the app

#if ANDROID

    Android.OS.Process.KillProcess(Android.OS.Process.MyPid());

#elif IOS

    System.Threading.Thread.CurrentThread.Abort();

#endif

}

}

In this modified version, the await MainPage.DisplayAlert ensures that the alert is shown to the user before calling the CloseApp method. This guarantees that the user sees the alert message before the app closes.

Additionally, the Shell.Current.GoToAsync("//LoginPage") call is also wrapped in MainThread.BeginInvokeOnMainThread to ensure it runs on the main thread.