First, register an ArcGIS developer account on the offciial website. After registration, download the ArcGIS Runtime SDK for Android from the developer dashboard.

Integrate the SDK into your Android project by extracting the downloaded archive and adding the .aar file to your project's libs folder. Then configure the build.gradle file:

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.aar'])
}

Next, generate a license key from the ArcGIS developer site under the "License Keys" section.

In your application's entry point, activate the license using the provided key:

// Initialize the ArcGIS runtime environment
LicenseResult result = ArcGISRuntimeEnvironment.setLicense("your_license_key_here");

// Verify activation status
if (result.getStatus() == LicenseStatus.VALID) {
    // License is active; proceed with map operations
} else {
    // Handle invalid license
}

Replace "your_license_key_here" with the actual key.

This process enables paid features of the ArcGIS Runtime API for Android. Ensure that the license key is kept secure and not exposed in client-side code if possible.