Platform-specific Initialization versus .NET MAUI Application Class

Question

Under Xamarin, the Application class Xamarin.Forms.Application depends on the LoadApplication(new App) call that need to be executed during a platform-specific launch.

With .NET MAUI, the Application class Microsoft.Maui.Controls.Application now has a life of its own. It means that with .NET MAUI, the Application class can be executed before platform-specific initialization prerequisites are completed. Migration from Xamarin to .NET MAUI will therefore require to take care of this important difference.

An ad-hoc approach can be taken to solve the problem so as to sync platform-specific initialization with dependent code in the .NET MAUI Application class and subsequent user code. As important the .NET MAUI Application lifecycle is, I am assuming that there may be a solution that is robust out there, as opposed to an ad-hoc approach.

SCENARIO EXAMPLE:

I'm using Plugin.Fingerprint package for fingerprint sensor based security. The package requires initialization during platform launch, for instance, for Android CrossFingerprint.SetCurrentActivityResolver(() => this); initialization is required in MainActivity OnCreate().

The issue is that the fingerprint sensor code can be reached before the required platform initialization.

Is there a recommended approach to solving this issue?

Answer 1

Hello,

The issue is that the fingerprint sensor code can be reached before the required platform initialization.Is there a recommended approach to solving this issue?

You can add your code of initialization to the MauiProgram.cs and wrap the Conditional compilation for Platform-specific code like the following code.

   public static class MauiProgram  
   {  
       public static MauiApp CreateMauiApp()  
       {  
           var builder = MauiApp.CreateBuilder();  
   #if ANDROID  
   // execute your android init code  
   #elif IOS  
   // execute your iOS init code  
   #else  
   // execute other platform init code  
     
   #endif  
     
           builder  
               .UseMauiApp<App>()  
               .ConfigureFonts(fonts =>  
               {  
                   fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");  
                   fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");  
               }) ;  
          return builder.Build();  
       }  
   }  

Best Regards,

Leon Lu

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