Biometrics on Android

Question

Hello, everyone from Stackoverflow. I’m a beginner in Android development, and I just developed an application, now I want to improve it, putting as input into the same biometric system, so that has a home screen with a button enter, When you click on this button I want there to be a system authentication with the biometric(as) registered(as) and if checking, then the user is taken to another Activity. I have researched, I looked on the Android Developers site, I searched here on Stackoverflow both Portuguese and English, but I did not find anything that would help me, has this similar question already open, but no answer,

/questions/354480/solicitar-permissão-para-autenticação-biometrica

If anyone can help me I am very grateful. I am developing an app for android 8.0 or higher. Any questions just ask.

I know that in the current android need to ask permission to the user when he starts the app or before using the service, It is another thing I do not understand how I need to do.

I thank you for your attention and any help is welcome.

Answer 1

Dear Gabriel, it follows the Mainactivity, XML class and the dependencies that must be informed in build.gradle. Doing so is no mistake and you can open your application with digital, because I use this code in all my applications as LOGIN.

package ricciandroid.com.br.biometria;

        import android.os.Bundle;
        import android.view.View;
        import android.widget.Button;
        import android.widget.Toast;

        import androidx.annotation.Nullable;
        import androidx.appcompat.app.AppCompatActivity;

        import com.an.biometric.BiometricCallback;
        import com.an.biometric.BiometricManager;

public class MainActivity extends AppCompatActivity implements BiometricCallback {

    private Button button;
    BiometricManager mBiometricManager;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        button = findViewById(R.id.btn_authenticate);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                /*
                 *
                 * */
                mBiometricManager = new BiometricManager.BiometricBuilder(MainActivity.this)
                        .setTitle(getString(R.string.biometric_title))
                        .setSubtitle(getString(R.string.biometric_subtitle))
                        .setDescription(getString(R.string.biometric_description))
                        .setNegativeButtonText(getString(R.string.biometric_negative_button_text))
                        .build();

                //start authentication
                mBiometricManager.authenticate(MainActivity.this);
            }
        });
    }


    @Override
    public void onSdkVersionNotSupported() {
        Toast.makeText(getApplicationContext(), getString(R.string.biometric_error_sdk_not_supported), Toast.LENGTH_LONG).show();
    }

    @Override
    public void onBiometricAuthenticationNotSupported() {
        Toast.makeText(getApplicationContext(), getString(R.string.biometric_error_hardware_not_supported), Toast.LENGTH_LONG).show();
    }

    @Override
    public void onBiometricAuthenticationNotAvailable() {
        Toast.makeText(getApplicationContext(), getString(R.string.biometric_error_fingerprint_not_available), Toast.LENGTH_LONG).show();
    }

    @Override
    public void onBiometricAuthenticationPermissionNotGranted() {
        Toast.makeText(getApplicationContext(), getString(R.string.biometric_error_permission_not_granted), Toast.LENGTH_LONG).show();
    }

    @Override
    public void onBiometricAuthenticationInternalError(String error) {
        Toast.makeText(getApplicationContext(), error, Toast.LENGTH_LONG).show();
    }

    @Override
    public void onAuthenticationFailed() {
//        Toast.makeText(getApplicationContext(), getString(R.string.biometric_failure), Toast.LENGTH_LONG).show();
    }

    @Override
    public void onAuthenticationCancelled() {
        Toast.makeText(getApplicationContext(), getString(R.string.biometric_cancelled), Toast.LENGTH_LONG).show();
        //mBiometricManager..cancelAuthentication();
    }



    @Override
    public void onAuthenticationSuccessful() {
        Toast.makeText(getApplicationContext(), getString(R.string.biometric_success), Toast.LENGTH_LONG).show();
    }

    @Override
    public void onAuthenticationHelp(int helpCode, CharSequence helpString) {
//        Toast.makeText(getApplicationContext(), helpString, Toast.LENGTH_LONG).show();
    }

    @Override
    public void onAuthenticationError(int errorCode, CharSequence errString) {
//        Toast.makeText(getApplicationContext(), errString, Toast.LENGTH_LONG).show();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent"
    android:orientation="vertical">


    <Button
        android:id="@+id/btn_authenticate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="60dp"
        android:drawableLeft="@drawable/connect"
        android:text="@string/btn_authenticate" />

</RelativeLayout>

NO BUILD.GRADLE INSERT THESE DEPENDENCIES

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'com.google.android.material:material:1.0.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'

    implementation(group: 'com.an.biometric', name: 'biometric-auth', version: '0.1.0', ext: 'aar', classifier: '')
}