IssueTracker

BUILD INFO

• Device type: Emulator and physical
• OS version: 10
• Biometric library version: 1.1.0

STEPS TO REPRODUCE

1. Use an Android 10 device that has a PIN/Swipe pattern but no fingerprint/biometrics
2. Turn on the "Don't Keep Activities" developer option
3. Request a biometric authentication using BiometricPrompt.authenticate
4. Enter the correct PIN/Swipe pattern in on the authentication screen

EXPECTED RESULTS The AuthenticationCallback provided to BiometricPrompt is called appropriately

OBSERVED RESULTS The AuthenticationCallback is not called at all

NUMBER OF TIMES YOU WERE ABLE TO REPRODUCE (e.g. 3/10) 10/10

ADDITIONAL INFORMATION Because the part of the BiometricPrompt code is implemented differently on different distributions of the Android OS, it is possible that this same bug can occur when authenticating from the fingerprint/biometric screens as well as on the device credential screen (e.g. some Samsung devices appear to use an Activity for the fingerprint/biometric screen, which causes this same issue to occur). However, using an emulator with Android 10 and the device credentials flow is the easiest way to reproduce this bug.

This same bug does not occur if the platform's android.hardware.biometrics.BiometricPrompt is used instead.

Below is some example code for an Activity that will reproduce the issue describe above. In this example, you would expect to see a toast if the AuthenticationCallback was called successfully.

class ExampleActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val biometricPrompt = BiometricPrompt(
            this,
            ContextCompat.getMainExecutor(this),
            object : BiometricPrompt.AuthenticationCallback() {
                override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
                    Toast.makeText(this@ExampleActivity, "onAuthenticationError", Toast.LENGTH_LONG).show()
                }

                override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
                    Toast.makeText(this@ExampleActivity, "onAuthenticationSucceeded", Toast.LENGTH_LONG).show()
                }

                override fun onAuthenticationFailed() {
                    Toast.makeText(this@ExampleActivity, "onAuthenticationFailed", Toast.LENGTH_LONG).show()
                }
            }
        )

        val button = Button(this).apply {
            text = "Authenticate"
            setOnClickListener {
                biometricPrompt.authenticate(
                    BiometricPrompt.PromptInfo.Builder()
                        .setTitle("EXAMPLE")
                        .setSubtitle("EXAMPLE")
                        .setAllowedAuthenticators(
                            Authenticators.BIOMETRIC_STRONG or
                            Authenticators.BIOMETRIC_WEAK or
                            Authenticators.DEVICE_CREDENTIAL
                        )
                        .build()
                )
            }
        }

        setContentView(button)
    }
}