In blog Better Biometrics in Android P they said: "To keep users safe, most apps and devices have an authentication mechanism, or a way to prove that you're you. These mechanisms fall into three categories: knowledge factors, possession factors, and biometric factors. Knowledge factors ask for something you know (like a PIN or a password), possession factors ask for something you have (like a token generator or security key), and biometric factors ask for something you are (like your fingerprint, iris, or face)".
But when I read in BiometricPrompt API, I can't see document for iris or face, authenticate only support for fingerprint: "This call warms up the fingerprint hardware, displays a system-provided dialog, and starts scanning for a fingerprint. It terminates when BiometricPrompt.AuthenticationCallback.onAuthenticationError(int, CharSequence) is called..." How I can use Biometrics to create authentication login with iris and face or any other solution for this?
Android 9 only includes support for the Fingerprint aspect of biometric authentication. Iris and facial recognition will be supported down the line. Note that this results in the deprecation of the previous FingerprintManager APIs when writing apps for Android P.
Android 9 only includes fingerprint integration for BiometricPrompt. However, integrated support for other biometric modalities are forthcoming.
来源：https://stackoverflow.com/questions/51146127/biometrics-with-iris-and-face-recognition