Remove MRKT3 Android's dependency on MR OpenXR Plugin.

[AMollis]

This issue has been migrated a new MRTK repository, and the status of this issue will now be tracked at the following location:

• https://github.com/MixedRealityToolkit/MixedRealityToolkit-Unity/issues/124

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Overview

The Mixed Reality OpenXR Plugin v1.8.0 removed support for Android. Andriod is no longer being supported by Microsoft's plug-in. Unfortunately, MRTK3 still relies on the MR OpenXR Plugin for Android Hand Joints.

Fix

Instead of relying on the MR OpenXR Plugin for Android Hand Joints, MRTK3 should use other methods for obtaining hand joints.

[mschult2]

I think I have a similar problem. But I'm not even building Android w/ OpenXR, I'm building Android w/ ARCore. No MRTK needed for my Android mobile target.

Even so, the mere presence of the MRTK package is causing the build to fail.

Any workarounds?

Library\PackageCache\com.microsoft.mrtk.input@473ce5ad9479\Subsystems\Hands\OpenXRHandsSubsystem.cs(8,30): error CS0234: The type or namespace name 'OpenXR' does not exist in the namespace 'Microsoft.MixedReality' (are you missing an assembly reference?)

[AMollis]

@mschult2, before we resolve this issue, you have to downgrade to an earlier version MR Open XR Plugin. Trying switching to v1.7.2

https://github.com/microsoft/OpenXR-Unity-MixedReality-Samples/releases/tag/v1.7.2

Or you can update the MRTKs' assembly metadata files, so they don't build for Android.

[AMollis]

Open XR v1.8.1 added Android support back. So this is no longer needed

• https://github.com/microsoft/OpenXR-Unity-MixedReality-Samples/releases/tag/v1.8.1

[mschult2]

Great! I’ll upgrade OpenXR 1.8.0 to 1.8.1, then rebuild my MRTK app for Android.