生物识别提示未显示面部解锁提示

Question

I am trying to authenticate my app with fingerprint as well as face unlock depending upon user has setup authentication for his device.Now in my app I want face unlock which is not getting displayed.For that I have removed finger prints but it never comes up.My device supports Android 10.I know oem select what to show ie fingerprint or face prompt.How can i check whether my app supports face unlock. Below is my implementation

Gradle :
 implementation "androidx.biometric:biometric:1.0.1"

Code Implementation:

public class MainActivity extends AppCompatActivity {

    Button btnHello;
    Executor executor;
    BiometricPrompt.PromptInfo promptInfo;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        executor = ContextCompat.getMainExecutor(this);
        final BiometricPrompt biometricPrompt = new BiometricPrompt(MainActivity.this,
                executor, new BiometricPrompt.AuthenticationCallback() {
            @Override
            public void onAuthenticationError(int errorCode,
                                              @NonNull CharSequence errString) {
                super.onAuthenticationError(errorCode, errString);
                Toast.makeText(getApplicationContext(),
                        "Authentication error: " + errString, Toast.LENGTH_SHORT)
                        .show();
            }

            @Override
            public void onAuthenticationSucceeded(
                    @NonNull BiometricPrompt.AuthenticationResult result) {
                super.onAuthenticationSucceeded(result);
                Toast.makeText(getApplicationContext(),
                        "Authentication succeeded!", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onAuthenticationFailed() {
                super.onAuthenticationFailed();
                Toast.makeText(getApplicationContext(), "Authentication failed",
                        Toast.LENGTH_SHORT)
                        .show();
            }
        });

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

        // Prompt appears when user clicks "Log in".
        // Consider integrating with the keystore to unlock cryptographic operations,
        // if needed by your app.
        Button biometricLoginButton = findViewById(R.id.btnHello);
        biometricLoginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                biometricPrompt.authenticate(promptInfo);
            }
        });
    }







}

Answer 1

BiometricManager biometricManager = BiometricManager.from(this);
    switch (biometricManager.canAuthenticate()) {
        case BiometricManager.BIOMETRIC_SUCCESS:
            Log.d("MY_APP_TAG", "App can authenticate using biometrics.");
            break;
        case BiometricManager.BIOMETRIC_ERROR_NO_HARDWARE:
            Log.e("MY_APP_TAG", "No biometric features available on this device.");
            break;
        case BiometricManager.BIOMETRIC_ERROR_HW_UNAVAILABLE:
            Log.e("MY_APP_TAG", "Biometric features are currently unavailable.");
            break;
        case BiometricManager.BIOMETRIC_ERROR_NONE_ENROLLED:
            Log.e("MY_APP_TAG", "The user hasn't associated " +
                    "any biometric credentials with their account.");
            break;

Answer 2

You really can't (I think). You can only determine if it supports a biometric implementation, not which specific one it is (ie you can say it supports biometrics, but not that it supports fingerprint or face recognition). You likely can't see the face recognition option because your device is not capable of STRONG (vs WEAK) biometric through the face id (on Samsungs, for example, the fingerprint is STRONG, but the face id is WEAK).