KeepScreenOn throws error on Android

Jassim Al Rahma 1,516 Reputation points
2023-03-15T19:56:19+00:00

Hi,

I am trying the following:

DeviceDisplay.KeepScreenOn = true;

inside the App,xaml.cs and it's working fine on iOS but when I run it on Android I get below error:

System.NullReferenceException: The current Activity can not be detected. Ensure that you have called Init in your Activity or Application class.
  at Microsoft.Maui.ApplicationModel.ActivityStateManagerExtensions.GetCurrentActivity(IActivityStateManager manager, Boolean throwOnNull) in D:\a\_work\1\s\src\Essentials\src\Platform\ActivityStateManager.android.cs:95
  at Microsoft.Maui.Devices.DeviceDisplayImplementation.SetKeepScreenOn(Boolean keepScreenOn) in D:\a\_work\1\s\src\Essentials\src\DeviceDisplay\DeviceDisplay.android.cs:28
  at Microsoft.Maui.Devices.DeviceDisplayImplementationBase.set_KeepScreenOn(Boolean value) in D:\a\_work\1\s\src\Essentials\src\DeviceDisplay\DeviceDisplay.shared.cs:106
  at Microsoft.Maui.Devices.DeviceDisplay.set_KeepScreenOn(Boolean value) in D:\a\_work\1\s\src\Essentials\src\DeviceDisplay\DeviceDisplay.shared.cs:56
  at DataEye.App..ctor() in /Users/jassim/Projects/DataEye/DataEye/App.xaml.cs:17
  at at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
  at at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
  at at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeResolverContext, Microsoft.Extensions.DependencyInjection, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].VisitCallSiteMain(ServiceCallSite callSite, RuntimeResolverContext argument)
  at at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
  at at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeResolverContext, Microsoft.Extensions.DependencyInjection, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].VisitCallSite(ServiceCallSite callSite, RuntimeResolverContext argument)
  at at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
  at at Microsoft.Extensions.DependencyInjection.ServiceProvider.CreateServiceAccessor(Type serviceType)
  at at System.Collections.Concurrent.ConcurrentDictionary`2[[System.Type, System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Func`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope, Microsoft.Extensions.DependencyInjection, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].GetOrAdd(Type key, Func`2 valueFactory)
  at at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
  at at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
  at Microsoft.Maui.MauiContext.WrappedServiceProvider.GetService(Type serviceType) in D:\a\_work\1\s\src\Core\src\MauiContext.cs:68
  at Microsoft.Maui.MauiContext.WrappedServiceProvider.GetService(Type serviceType) in D:\a\_work\1\s\src\Core\src\MauiContext.cs:68
  at at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[IApplication](IServiceProvider provider)
  at at Microsoft.Maui.Hosting.SentryMauiAppBuilderExtensions.BindMauiEvents(IPlatformApplication platformApplication)
  at at Microsoft.Maui.Hosting.SentryMauiAppBuilderExtensions.<>c.<RegisterMauiEventsBinder>b__3_2(Application application)
  at Microsoft.Maui.MauiApplication.<OnCreate>b__2_0(OnApplicationCreating del) in D:\a\_work\1\s\src\Core\src\Platform\Android\MauiApplication.cs:35
  at Microsoft.Maui.LifecycleEvents.LifecycleEventServiceExtensions.InvokeLifecycleEvents[OnApplicationCreating](IServiceProvider services, Action`1 action) in D:\a\_work\1\s\src\Core\src\LifecycleEvents\LifecycleEventServiceExtensions.cs:31
  at Microsoft.Maui.MauiApplication.OnCreate() in D:\a\_work\1\s\src\Core\src\Platform\Android\MauiApplication.cs:35
  at Android.App.Application.n_OnCreate(IntPtr jnienv, IntPtr native__this) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Android.App.Application.cs:1072
  at Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PP_V(_JniMarshal_PP_V callback, IntPtr jnienv, IntPtr klazz) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:22

KIndly help..

Thanks,

Jassim

.NET MAUI
.NET MAUI
A Microsoft open-source framework for building native device applications spanning mobile, tablet, and desktop.
2,834 questions
{count} votes

2 answers

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  1. Leon Lu (Shanghai Wicresoft Co,.Ltd.) 67,781 Reputation points Microsoft Vendor
    2023-03-23T09:38:14.2966667+00:00

    Hello,

    From MAUI github issue:DeviceDisplay.Current.KeepScreenOn = true isn't working

    It is a timing issue. The actual implementation of KeepScreenOn in Android depends on setting WindowManagerFlags on the current Activity's Window; if KeepScreenOn = true is called in the cross-platform application before the Window is actually available, then it won't do anything.

    Here is a solution, you can put this code to the windows create method like following code.

    public partial class App : Application
    {
        public App()
        {
            InitializeComponent();       
            MainPage = new AppShell();
        }
       protected override Window CreateWindow(IActivationState activationState)
        {
            Window window = base.CreateWindow(activationState);
    
           window.Created += (s, e) =>
            {
                DeviceDisplay.KeepScreenOn = true;
            };
    
           return window;
        }
    
    }
    

    Best Regards,

    Leon Lu


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  2. Auto 41 Reputation points
    2024-04-17T14:36:53.6866667+00:00

    I used to call (DeviceDisplay.KeepScreenOn = true) in the constructor of the page and now - on Android with .NET MAUI - I get the same error:

    "The current Activity can not be detected. Ensure that you have called Init in your Activity or Application class."

    To solve the problem I did in this way at the end of the constuctor of the page:

    MainThread.BeginInvokeOnMainThread(async () =>
    {
        await Task.Delay(1500);  
        DeviceDisplay.KeepScreenOn = true;
    });
    
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