Akavache: Crash at System.Reactive.Linq.Observable.SelectMany

This is my take on the code to resolve this issue:

        Akavache.BlobCache.Shutdown().Wait();  // this calls the shutdown code
        Akavache.BlobCache.LocalMachine = null; // clear out the static cached variables
        Akavache.BlobCache.Secure = null;
        Akavache.BlobCache.UserAccount = null;
        FieldInfo fi = typeof(Akavache.BlobCache).GetField("shutdownRequested", BindingFlags.Static | BindingFlags.NonPublic );
        fi.SetValue(null, false); // reset the private flag
        Splat.Locator.Current = new Splat.ModernDependencyResolver(); // create a new dependency resolver so akavache has to create new objects when the app is resurrected.

This code is in the MainActivity.OnDestroy override

I believe I am seeing the same issue. For me, the exception (System.ArgumentNullException: Value cannot be null.Parameter name: source) is a repeatable fault which occurs only after the App is resumed after being suspended. (Note: I am relatively new to X-Forms so it is entirely possible that, in my case, it is operator error)

I have attached a sample VS 2015 Xamarin Forms project (Droid only) which is failing reliably on my system. Here are the steps to reproduce.

• Target Nexus 4 (KitKat) (Android 4.4 - API 19) using the Xamarin Android Player)
• Start the app in Debug mode. It should startup and display “We have 5 cats!”
• Suspend the app using the Back button (Important… don’t use the Home button)
• Restart the app by selecting the app icon on the emulator. The app should throw the exception on the call to GetOrFetchObject.

App3.zip

Hi, same here.

Is there an alternative to static BlobCache.XXXX ? For example, we could instantiate directly an IBlobCache and keep control over that instance.

Xamarin.Forms provides us 3 events to be aware about app lifecycle : OnStart, OnResume and OnSleep, so when app is going to sleep, we can just call Flush() on the BlobCache instance for example. Or, maybe we can Dispose() the instance (or Shutdown it ?), then re-instanciating it when app resumes.

@paulcbetts Any advice about that and getting rid of BlobCache static class ?

I worked around this by moving the call to BlobCache.Shutdown().Wait(); within the OnDestroy of my main activity, rather than OnStop.