On this repository you'll find an experiment to draw the Native Android Camera feed onto a Unity GameObject.
The inspiration comes from Unity Technologies NativeRenderingPlugin.
The folder structure contains the following code:
1 An NDK library as the low level rendering plugin
2 An Android Studio project to create and AAR library as Unity Native Plugin
3 Finally, the Unity project to illustrate all the plumbing
Upon success you'll see something like the below image on your Android device:
If you have trouble building the Unity project, please try the following:
Open "Build Settings" and make sure:
"Android" is selected in the Platform panel;
the Build System dropbox is showing "Internal".
This should allow you to build successfully.