Add our library to your Android app

Learn how to add our biometric authentication library to your Android or iOS app so you can test biometric authentication during your manual and automated test sessions.

Before you start

Before you can add our library to your app, create a test version of your app and disable your .CryptoObject classes, or ensure your app meets the following:

✓

Only supports Android 9 or later.

✓

Uses classes with lower-level security, like BiometricPrompt.AuthenticationCallback or BiometricPrompt.PromptInfo.

✗

Does not use classes with higher-level security, like BiometricPrompt.CryptoObject.

✗

Does not use deprecated classes, like FingerprintManager.

Add KobitonBiometric.aar

First you’ll open your app’s Android Studio project and create a libs directory inside your project’s app directory if you don’t already have one. Then download and move KobitonBiometric.aar into your new libs directory.

Modify build.gradle

Next you’ll open the build.gradle in your app directory and add our library (or all your .aar libraries) to your list of dependencies:

    implementation fileTree(dir: 'libs', include: ['<library>']) // Replace <library> with KobitonBiometric.aar or *.arr.
Example
dependencies {
    implementation fileTree(dir: 'libs', include: ['KobitonBiometric.aar']) // Alternatively, replace KobitonBiometric.aar with *.arr to include all libraries.
    implementation 'org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version'
    implementation 'androidx.core:core-ktx1.3.0'
    implementation group: 'com.google.android.material', name: 'material', version: '1.3.0-alpha01'

    testImplementation 'junit:junit:4.13'

    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

}

When you’re finished, save your file.

Modify AndroidManifest. xml

Next you’ll open the AndroidManifest.xml file in /app/src/main and add the following lines to your <manifest> element:

<uses-permission android:name="android.permission.USE_BIOMETRIC" android:requiredFeature="false"/>
<uses-permission android:name="android.permission.INTERNET"/>

Locate your <application> element and add the following line:

android:usesCleartextTraffic="true"

Inside <application>, replace:

  • *.BiometricManager classes with com.kobiton.biometric.BiometricManager

  • *.BiometricPrompt with com.kobiton.biometric.BiometricPrompt

Example
$EXAMPLE$

When you’re finished, save your file and verify your changes.

Verify your changes

First, rebuild your .apk and upload it to the app repository. Then, start a manual test session, launch your app, and try using biometric authentication to sign in. Select Pass and check the logs to verify your changes.

Known issues

If you add our library to your app and send BiometricPrompt.AuthenticationCallback during authentication using toasts, your app may crash during your test session. If this happens, you’ll find the following error in your crash logs:

java.lang.NullPointerException: Can't toast on a thread that has not called Looper.prepare()

Here’s a script that could lead to a crash:

private BiometricPrompt.AuthenticationCallback getAuthenticationCallback() {
    return new BiometricPrompt.AuthenticationCallback() {
        @Override
        public void onAuthenticationError(int errorCode, @NonNull CharSequence errString) {
            Toast.makeText(MainActivity.this, "Authentication error", Toast.LENGTH_SHORT).show();
            super.onAuthenticationError(errorCode, errString);
        }

        @Override
        public void onAuthenticationSucceeded(@NonNull BiometricPrompt.AuthenticationResult result) {
            Toast.makeText(MainActivity.this, "Authentication successful", Toast.LENGTH_SHORT).show();
            super.onAuthenticationSucceeded(result);
        }

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