Xamarin: Block sleep mode while running a process

Question

Sometimes it is required to turn off sleep mode in the application while a lengthy process is running. When the process has done, sleep mode can be turned on again.

How to do that in Xamarin, for Android and iOS projects?

Answer 1

We'll make an interface and use DependencyService to run platform-specific implementation in the platform-agnostic project.

In the platform agnostic project create an interface:

namespace MyCompany.Services {
    public interface ISleepModeHandler
    {
        public void BlockSleepMode(bool blockSleepMode);
    }
}

In the Android project:

1. In the AndroidManifest.xml file, add this permission:

    <uses-permission android:name="android.permission.WAKE_LOCK" />

2. Add Xamarin.Essentials dependency to the platform-agnostic and to the android project. And don't forget to initialize Xamarin.Essentials in the android project.

3. Create the class:

using Android.Views;
using MyCompany.Android.Services;
using MyCompany.Services
using Xamarin.Essentials;
using Xamarin.Forms;
    
[assembly: Dependency(typeof(SleepModeHandlerForDroid))]
namespace MyCompany.Android.Services
{
    public class SleepModeHandlerForDroid : ISleepModeHandler
    {
        public void BlockSleepMode(bool blockSleepMode)
        {
            Xamarin.Forms.Device.BeginInvokeOnMainThread(() => 
            { 
                MainActivity activity = (MainActivity)Platform.CurrentActivity;

                if (blockSleepMode)
                {
                    activity.Window.AddFlags(WindowManagerFlags.KeepScreenOn);
                }
                else
                {
                    activity.Window.ClearFlags(WindowManagerFlags.KeepScreenOn);
                }
            });
        }
    }
}

4. In iOS project create the class:

using MyCompany.Services;
using MyCompany.iOS.Services;
using UIKit;
using Xamarin.Forms;

[assembly: Dependency(typeof(SleepModeHandlerForiOS))]
namespace MyCompany.iOS.Services
{
    [Foundation.Preserve(AllMembers = true)]
    public class SleepModeHandlerForiOS : ISleepModeHandler
    {
        public void BlockSleepMode(bool blockSleepMode)
        {
            Xamarin.Forms.Device.BeginInvokeOnMainThread(() => 
            {
                UIApplication.SharedApplication.IdleTimerDisabled = blockSleepMode;
            });
        }
    }
}

That's it. Now, in platform agnostic module, when you want to block sleep mode while processing, and turn it on afterwards use the following approach:

ISleepModeHandler sleepModeHandler = DependencyService.Get<ISleepModeHandler>();
sleepModeHandler.BlockSleepMode(true); // blocking the sleep mode

// your process goes here

sleepModeHandler.BlockSleepMode(false); // allowing the sleep mode again