Xamarin.Forms Maps + Admob crashes on Android 10+

Ian Hill 6 Reputation points

I'm new to C#/.Net/Xamarin. I’ve been playing with it over the past two months in my spare time.

I'm hoping someone will be able to help me with this.

I’ve written an app that uses both Xamarin.Forms Maps and Admob. It attempts to display both a map and a banner ad on the main page. I’ve used typical admob renderers for iOS and Android that I’ve found online. The app works fine on iOS, but it crashes on Android, just as the ad displays. In the device log and output screen, it indicates a fatal SIGSEGV, just after the ad loads:

BannerListener: the Ad has loaded
[libc] Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0 in tid 20590 (RenderThread), pid 20544 (com.AdTest)

If I eliminate either the map, or the ad, the other works fine. It’s only when both views try to load at the same time that it crashes, and it crashes on Android 11 and 10, but not 9 or 8. The build targets 11. I’ve tested primarily on emulators, but I’ve tried a physical Android 8 device, and it works fine.
I’ve written a minimal project to demonstrate this. It’s on github at https://github.com/ighill/AdMapsCrash

The project includes the testads app_id and ad_id, but not a google maps api_key. You’ll have to add your own to the manifest file, although it seems to crash even with nonsense in place of the api_key – it just leaves the map blank.

Note that I add the two views programmatically in MainPage.xaml.cs, but it behaves exactly the same if they are defined in xaml.

Also, if I delay the loading of the map by including a button that triggers the map to load, and I press it after the ad appears, the map loads fine, and it will continue to run, updating the ad periodically.

At the top of MainPage.xaml.cs, I have three compiler directives, WITHADS, WITHMAP and BUTTON that control whether each is included. If BUTTON is not defined, and WITHMAP is, the map loads immediately (and crashes, if WITHADS is also defined).

I’m using Visual Studio 2019, with the most recent updates installed, and the following nuget package versions (all up to date as of this writing):

NetStandard.Library v2.0.3
Xamarin.Build.Download v0.10.0
Xamarin.Essentials v1.6.1
Xamarin.Forms v5.0.0.2012
Xamarin.Forms.Maps v5.0.0.2012
Xamarin.GooglePlayServices.Ads v119.7.0

Note that I’ve also tried it with the same version of Xamarin.Firebase.Ads, with the same results. Also, I’ve gone through a number of iterations of downgraded admob packages and corresponding Forms/Forms.Maps versions, with exactly the same results.

The github repository includes a file, output.txt, that contains the device.log output from a crashed run.
Thanks in advance. I hope someone can give me some insight into what I’m doing wrong!

A Microsoft open-source app platform for building Android and iOS apps with .NET and C#.
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  1. Alexey Gr 6 Reputation points

    Hi, I have the same problem. Only I have a Java project. Also map and advertisement. Haven't found a solution yet?

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  2. Ian Hill 6 Reputation points

    Unfortunately, I haven't. Good luck, and please let me know if you find a solution. I'll do the same.

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