Access Android Camera.Parameters from Unity

I would like to access the android defined class

Camera.Parameters.getHorizontalViewAngle()

from a Unity3D c# script but my java skills are limited. Can anybody offer any help? I have this code:

using UnityEngine;

#if UNITY_ANDROID
public class CameraParametersAndroid
{
    public static float HorizontalViewAngle { get; protected set; }
    public static float VerticalViewAngle   { get; protected set; }
    public static int   numCameras      { get; protected set; }

    static CameraParametersAndroid()
    {
        AndroidJavaClass unityPlayerClass = new AndroidJavaClass ("com.unity3d.player.UnityPlayer"),
                         cameraClass = new AndroidJavaClass ("android.hardware.Camera"),
                         cameraParametersClass = new AndroidJavaClass ("android.hardware.Camera.Parameters"),
                         cameraInfoClass = new AndroidJavaClass ("android.hardware.Camera.CameraInfo");

        AndroidJavaObject currentActivity = unityPlayerClass.GetStatic<AndroidJavaObject>("currentActivity");
        object[] args = {currentActivity};

        AndroidJavaObject camera = cameraClass.CallStatic<AndroidJavaObject>("getCamera", args);

        if (camera != null)
        {
            AndroidJavaObject cameraParameters = camera.Call<AndroidJavaObject>("getParameters");

            numCameras = camera.Call<int>("getNumberOfCameras");
            HorizontalViewAngle = cameraParameters.Call<float>("getHorizontalViewAngle");
            VerticalViewAngle   = cameraParameters.Call<float>("getVerticalViewAngle");

        }
        else
        {
            Debug.LogError("[CameraParametersAndroid] Camera not available");
        }
    }
}
#endif

but not even the getNumberOfCameras() call works.