Article on Medium: https://medium.com/@merail/incoming-call-handler-0c57e8ae7188

This Android app demonstrates examples of usage:

1. BroadcastReceiver for catching calls.
2. CallScreeningService for cathing calls with Android 10+.
3. Creating a window from the BroadcastReceiver/CallScreeningService.
4. Dragging the created window.

The following permissions are required to complete these steps:

1. android.permission.READ_PHONE_STATE.
2. android.permission.READ_CONTACTS.
3. android.permission.READ_CALL_LOG.
4. android.permission.SYSTEM_ALERT_WINDOW.

Also for Android 10+, the application needs to install the ROLE_CALL_SCREENING role.

Handling of incoming calls will also work when the application is closed and after a device reboot.

Note: Android Marshmellow may have problems with handling due to security policy.