Fix animated gifs in Release builds

[mattleibow]

Description of Change

I had to change the code a bit to prevent the linker from removing interfaces from types or something that I do not yet understand.

The old code would pass a URI to Glide and Glide would return a Drawable that may or may not be IAnimatable - for example, it could be AnimatedImageDrawable.

In Debug builds, the condition drawable is IAnimatable would return true, but in Release builds, this will be false. Checking the type, it was a Java AnimatedImageDrawable. The dotnet type is a DrawableInvoker since the dotnet type was linked out. This is a good thing because we can never use nor need the dotnet type. All we want is the Java interface.

@simonrozsival @jonathanpeppers does this make any sense to you as to why this would happen like this?

Issues Fixed

Fixes #12974

[simonrozsival]

I had to fix something similar earlier this year: dotnet/android#8594 I think you can fix this with a few [DynamicDependency] attributes to this method:

[DynamicDependency(nameof(IAnimatable))]
[DynamicDependency(nameof(AnimationD)rawable)]
[DynamicDependency(nameof(GifDrawable))]
[DynamicDependency(nameof(AnimatedImageDrawable))]

[jonathanpeppers]

Does no C# code use any of the above types? What @simonrozsival suggests seems like the right idea.

Something similar also happens here:

• https://github.com/xamarin/xamarin-android/blob/b521487d0226db265baaa83f0f53e2e75497c420/tests/Mono.Android-Tests/Android.Graphics/NinePatchTests.cs#L27-L34

Since no C# code uses NinePatchDrawable it's linked away. Mono.Android.dll and all the AndroidX libraries mark themselves trimmable.

[mattleibow]

The issue is that I don't know what types are being used - I know of some but it could be any type of drawable. I would have to list all of the known ones and then it would still not be super perfect because of third parties.

Also, since we don't use the type in C# - all the loading code is in Java now - we are otentially forcing a whole bunch of C# types to exist when we don't really need it.

[simonrozsival]

It doesn't seem like [DynamicDependency] is applicable in this case then. Doing the JavaCast might be the best way after all. Hopefully Proguard won't be messing up the Java side of things :)

[jonathanpeppers]

I'm not a fan of an empty try-catch with no logging.

Does a [DynamicDependency] like @simonrozsival suggested also solve it? That would have no performance cost, and I think things would still be trimmed away if you had 0 animated gifs in your app.

[mattleibow]

I logged an issue with a feature request or something: dotnet/android#9038

[Redth]

/azp run

[azure-pipelines]

Azure Pipelines could not run because the pipeline triggers exclude this branch/path.