Determine if biometric hardware is present and the user has enrolled biometrics on Android P

Question

I\'m asked to show certain UI elements depending on the presence of biometric hardware. For Android 23-27 I use FingerprintManager#isHardwareDetected() and

Answer 1

In my biometrics, I used these and a few more checks to make sure that the device was capable and the fingerprint was enabled. In Kotlin I created an Object class and called it utilities.

object BiometricUtilities {
    fun isBiometricPromptEnabled(): Boolean {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.P
    }
    fun isSdkVersionSupported(): Boolean {
    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.M
    }
    fun isHardwareSupported(context: Context): Boolean {
        val fingerprintManager = FingerprintManagerCompat.from(context)
        return fingerprintManager.isHardwareDetected
    }
    fun isFingerprintAvailable(context: Context): Boolean {
        val fingerprintManager = FingerprintManagerCompat.from(context)
        return fingerprintManager.hasEnrolledFingerprints()
    }
}

Then in my bioManager class, I placed the conditional statements under a function called authenticate that implements BiometricCallback

fun authenticate(biometricCallback: BiometricCallback) {

    if (!BiometricUtilities.isHardwareSupported(context)) {
        biometricCallback.onBiometricAuthenticationNotSupported()
        return
    }

    if (!BiometricUtilities.isFingerprintAvailable(context)) {
        val intent = Intent(Settings.ACTION_SECURITY_SETTINGS)
           biometricCallback.onBiometricAuthenticationNotAvailable()
        return
    }

    displayBiometricDialog(biometricCallback)
}

This way you can check for availability of hardware and presence of fingerprint on the device and let the OS help you to display a prompt or not