Images don't load in Xamarin.Forms 4 when using Visual=Material

[mikescandy]

As described in xamarin/Xamarin.Forms#4674, when using XF4 and setting the ContentPage Visual to Material, images don't load.
The visual code uses ContextThemeWrapper to apply Material themes to controls, but in GlideExtensions.cs:

 if (imageView.Context is Activity activity)
else
return;

Without the else images are loaded correctly.

[mikescandy]

I'm trying to produce a minimal case for this but I can't... (these bugs are killing me! 🤬🤬🤬)
I'll keep on trying....

[mikescandy]

Got it! Please find a repro at https://github.com/mikescandy/glidex/tree/wrapbug . I forgot that to trigger the issue I had to:

• upgrade to XF4
• upgrade to Support Libraries v28.0.0-preview8
• target Android 9.0
  BUT
  not for the binding project. I think there's a different Xamarin android bug there
  Anyway, this shows the issue (and it might be a good starting point if/when you plan to update to the latest libs)

[jonathanpeppers]

So I started a branch here to try all the new stuff: https://github.com/jonathanpeppers/glidex/compare/xf-4.0-pre

Main thing I saw was ImageCell broke the moment I upgraded to 4.x: #21

I'll look at what might be happening when glidex.csproj has a TargetFrameworkVersion=v8.1.

[mikescandy]

I think I saw an issue on xamarin.android that could be related to the binding project not compilinig, I'll see if I can link it here.
edit: dotnet/android#2465 (hey, look who created the issue 😅 )

[jonathanpeppers]

If the binding project had:

<PackageReference Include="Xamarin.Android.Support.v4" Version="28.0.0-preview9" />

Then you have to use TargetFrameworkVersion=v9.0, right?

[mikescandy]

no, I think support 28 can multitarget https://blog.xamarin.com/multi-targeting-with-android-support-library-v28/

[jonathanpeppers]

It is working for me, could it be that you have -preview8 in your example, and I have -preview9?

The other thing is I'm using a master build of Xamarin.Android + VS 2019: https://jenkins.mono-project.com/view/Xamarin.Android/job/xamarin-android-builds-master/656/PublishUrls/

[mikescandy]

I think the issue is fixed in master. I'll see if I can try that tomorrow too.

[jonathanpeppers]

The only thing I remember is this: dotnet/android#2424

I think you would get a build error on incremental builds, though.

[jonathanpeppers]

Oh sorry @mikescandy I didn't read!

I think I saw an issue on xamarin.android that could be related to the binding project not compilinig, > > I'll see if I can link it here.
edit: dotnet/android#2465 (hey, look who created the issue 😅 )

If that's the issue, yeah I fixed it in xamarin-android/master. Here is a workaround: 861719f

I think we can close this, unless you are seeing this in the Android device log:

glidex/glidex.forms/GlideExtensions.cs

Lines 28 to 30 in 4c32d3b

	} else {
	Forms.Warn ("Context `{0}` is not an Android.App.Activity, aborting image load for `{1}`.", imageView.Context, source);
	return;

[mikescandy]

I do see

12-14 15:01:10.569 W/glidex  ( 3824): Context `android.view.ContextThemeWrapper@f0bca8f` is not an Android.App.Activity, aborting image load for `Uri: https://growtix-melupufoagt.stackpathdns.com/media/big//34/28/23/5a9f03c2-3734-4486-bd04-2d45ac1c102e.png`.

[jonathanpeppers]

Ok I searched XF for ContextThemeWrapper, and looks like this would happen with <Image/> inside a <Frame/>:

<Frame>
    <Image WidthRequest="80" HeightRequest="80" Source="trump.png" />
</Frame>

MaterialFrameRenderer has a ContextThemeWrapper as its Context, and it would "pass it on" to its children.

[mikescandy]

That's how I triggered it in https://github.com/mikescandy/glidex/tree/wrapbug