Xamarin.Plugins | Cross platform Xamarin Plugins | Form library

While calling your application is getting to the background and is resumed when you hang up the call. If you don't save your state when the app is pushed to the background it will just start it like it's a fresh start.

In the Application class there are methods to override which you can use to save the state and check the state on resume. https://docs.microsoft.com/en-gb/xamarin/xamarin-forms/app-fundamentals/app-lifecycle

So my suggestion would be to store the state of the current phone number you're calling and on the resume check if there was a previous number called and continue from that number in your list.

After comparing with the official sample , I found the issue was that the timeout parameter you set is too short for the task completion, so it canceled every time.

Okay I finally found something that was useful. I found a clue on this page and some other information on the project issues page on Github.

Ultimately, to get the icon to display I used

The workaround I found was to declare de IconToolbarItem in the c# code instead of xaml. Although I don't know why it wasn't working while on xaml.

Declaring the item li

I'm putting in the answer here just in case someone else has the same problem as I do in the future. Also, since there's little documentation, and I had to cobble together this alternative solution from a Chinese website (of all places!) and discussion with some of the guys on Slate Prism-Forms channel, I thought it would be best to put it out there on the alternative solution so at least you get an rudimentary idea on to resolve the DependencyService issues, and workarounds using Autofac DI.

I do want to note that there is discussion going on the Prism GitHub that Prism's implementation of DependencyService should be depreciated and go through this alternative that I'm describing here in this post. So hopefully one of the guys on the development team will document it and give better code examples on what I'm showing here.

That said, on with the show...

Okay, so I found out the answer to the problem. Long story short, the problem is the Autofac container.

And now the long winded version.

From what I gathered Dan Siegel, of all the containers that Prism can implement for a IoC/DI container, I had to pick the one that doesn't play well with others!

Why, do I say that it doesn't play well? According to the Autofac documentation, the container is Immutable which means it cannot be modified once it's been built. So my hypothesis is that when Prism goes through the project and tries to add in the registration types of DependencyService, Autofac is balking because the container is already built and therefore the "Unhandled Exception" is being thrown.

That explains the issue, but not the solution.

And what is the solution? Well, it turns out that Brian (Lagunas) and Brian (Noyes) have implemented a new interface called IPlatformInitializer, and I therefore have no choice but to use ContainerBuilder.Update(container) to add in the new RegisterType, which implements the additional RegisterTypes for the DependencyService, and I had to implement it like this: