问我使用生物识别api，但在android 10中只显示手指身份验证而不显示面部身份验证

EN

 override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_face_id)

        biometricPrompt = BiometricPrompt(this, ContextCompat.getMainExecutor(this), object : BiometricPrompt.AuthenticationCallback() {

            override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
                super.onAuthenticationError(errorCode, errString)

               Log.d("Huang", " error $errString")
            }

            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
                super.onAuthenticationSucceeded(result)

                Log.d("Huang", " success")
            }

            override fun onAuthenticationFailed() {
                super.onAuthenticationFailed()

                Log.d("Huang", " fail")
            }
        })

        promptInfo  = BiometricPrompt.PromptInfo.Builder()
            .setTitle("Biometric login for my app")
            .setSubtitle("Log in using your biometric credential")
            .setNegativeButtonText("Use account password")
            .setDeviceCredentialAllowed(true)
            .build()

        val button = findViewById<Button>(R.id.login)
        button.setOnClickListener {

            biometricPrompt.authenticate(promptInfo)
        }
    }