CameraSelector.Builder().AddCameraFilter effectively unusable (cannot select specific camera lens) about androidx HOT 2 CLOSED

That works perfectly. : Java.Lang.Object, was the missing key.

Thank you so much. Up to you whether to leave this open; I did ask for help on a large C# Discord server and nobody who answered could figure it out either.

Note to anyone finding this later:
The list you return from filter must be modifiable (the Java implementation calls retainAll on it).

Therefore, simply returning the same list passed in (p0) will result in a Java.Lang.UnsupportedOperationException. Calling ToList() on it fixes it.

Also, LensFacing is not the same as the lens id. There doesn't seem to be a way to get that directly from CameraInfo, so you'll need to store that mapping in memory elsewhere and do a lookup.

from androidx.

I think it would be something like:

var selector = new CameraSelector.Builder ()
                    .AddCameraFilter (new MyCameraFilter ())
                    .Build ();

class MyCameraFilter : Java.Lang.Object, ICameraFilter {
    public IList<ICameraInfo> Filter (IList<ICameraInfo> p0) => p0.Where (c => c.LensFacing == 3);
}

from androidx.