Biometric prompt Login Activity

LoginActivity.kt

class LoginActivity : AppCompatActivity() {

    private lateinit var biometricPrompt: BiometricPrompt
    private lateinit var promptInfo: BiometricPrompt.PromptInfo

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)
        
        biometricPrompt = createBiometricPrompt()
        promptInfo = createPromptInfo()

        findViewById<Button>(R.id.fingerprintBtn).setOnClickListener { authenticate() }
    }

    private fun createBiometricPrompt(): BiometricPrompt {
        val executor = ContextCompat.getMainExecutor(this)

       private val biometricCallback = object : BiometricPrompt.AuthenticationCallback() {
        override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
            super.onAuthenticationSucceeded(result)
            Toast.makeText(
                this,
                "Authentication succeeded!", Toast.LENGTH_SHORT
            ).show()
            //TODO: call service login bio
        }

        override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
            super.onAuthenticationError(errorCode, errString)
            //Authenticate error handle e.g. Biomatric Sensor Locked, Too many attempts case
        }

        override fun onAuthenticationFailed() {
            super.onAuthenticationFailed()
            //Authenticate failed. e.g. Wrong fingerprint
        }
    }

        //The API requires the client/Activity context for displaying the prompt view
        val biometricPrompt = BiometricPrompt(this, executor, callback)
        return biometricPrompt
    }

    private fun buildBiometricPrompt(): BiometricPrompt.PromptInfo {
        return BiometricPrompt.PromptInfo.Builder()
            .setTitle(getString(R.string.bio_authen_title))
            .setDescription(getString(R.string.bio_authen_description))
            .setNegativeButtonText(getString(R.string.bio_authen_negative_button))
            .setConfirmationRequired(false) //Allows user to authenticate without performing an action, such as pressing a button, after their biometric credential is accepted.
            .setAllowedAuthenticators(BIOMETRIC_WEAK)
            .build()
    }

    private fun authenticate() {
        if (checkCanAuthenticate()) {
            biometricPrompt.authenticate(promptInfo)
        }
    }
    
    private fun checkCanAuthenticate(): Boolean {
        return BiometricManager.from(applicationContext).canAuthenticate(BIOMETRIC_WEAK) == BiometricManager.BIOMETRIC_SUCCESS
    }

}