Xamarin.android Apk Crashes Following Migration To Visual Studio Team Services (vsts)

We've got a mobile application (Xamarin.Forms for iOS and Android) that we've been in the progress of migrating from our on-premise Team Foundation Server (TFS) to Visual Studio Te

Solution 1:

As it turns out, updating Xamarin.Forms is the solution.

Though suggested as resolution to the same error as ours on the Xamarin forums, and something I had come across before, the age of the post and the old version of Xamarin.Forms involved made me disregard this option as less relevant to our problem. What didn't help either was that I thought we were already on the highest version of Xamarin.Forms 2.5.1, and are not quite ready to move to Xamarin.Forms 3.0 yet. Yesterday, however, I discovered there was still a revision we could upgrade within the 2.5.1-branch, which is what I did. When I then tried a build with this code, surprisingly the resulting APK turned out to run without any issue!

The reason why updating Xamarin.Forms works is unclear to us, though. We did, however, observe that this particular version of Xamarin.Forms, 2.5.1.527436, was released just about a week before I migrated our build definition from TFS to VSTS. It might therefore be that there's some correlation there.

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Edit 1

Ran into some trouble with Xamarin.Forms 2.5.1.527436 today, which has eventually led me to the most likely cause for our problems creating an Android build of our App. That is, in order to resolve a crash caused by Xamarin.Forms, I tried to revert Forms to the last version I knew still worked. However, the problem with Xamarin.Forms persisted, even after the downgrade. This triggered me to inspect the project-files and compare the working version of the App to that which had been downgraded, yet should have ended up the same notwithstanding.

As it turns out some project files had references to two different versions of Xamarin.Forms: the one that I had intended to use, and the one we had been using before that. Now this mixture didn't cause any problems while running on a local development machine, since this machine would have both old and new versions of Xamarin.Forms installed and there would therefore not be any missing assemblies. However, I can imagine that this would not be the case when running a VSTS-build on a build-server. Moreover, the project files containing the incorrect assembly references were both Android projects - which explains why iOS had no trouble building...!