Xamarin Forms Detect if Screen Active and/or Device Locked

Question

I have a Xamarin Forms app that produces background audio and thus the app can run while the device is in lock mode and/or when the screen is not active (screen sleep).

I have a need to prevent screen updates while the Xamarin Forms MainPage (a ContentPage) is not visible and active. In other words, I need to detect is the screen is disabled (in sleep mode), if the device is locked, and also preferably when the MainPage is not currently active and visible.

Using Xamarin Forms, how can I detect if the screen is not active and/or if the device is in lock mode?

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Additional Info

• I tried using Xamarin.Essentials and checking the ScreenLock.IsActive property. This did not work, as IsActive was always false even when the device was in lock mode. Tested on iOS device (iPhone).
• The reason why I need to prevent screen updates is because I am using CocosSharp and I am periodically placing CCParticle animations on the screen. When the screen is not active, new CCParticle animations can continue to be added, but the existing ones do not run to their set duration and thus never "expire." The result is an ever-increasing number of CCParticle animations on the (hidden) screen that continuously consume resources.

Answer 1

In your App.xaml.cs, you have the following methods:

protected override void OnStart()
{
    // Handle when your app starts
}

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

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

It sounds like you want stuff to happen when the app starts/resumes, but not when it sleeps (when the screen is inactive, or the app is in the background).