CallFilter is a simple Android application that helps users to filter unknown incoming calls. The application will do screening of incoming calls and will take any action only if this incoming number is not saved in the user's contact directory.

Users can take any one of the following actions on unknown incoming calls:

Silent: This option will silence all unknown incoming calls by default, all other things remain the same. Like notification will be displayed, call log will be recorded.

Reject: This option will reject all unknown incoming calls, other things will remain the same.

Ringtone: This option will open the ringtone picker to select a custom ringtone. That selected ringtone will be played on unknown incoming calls. If no ringtone is selected then the call will be passed to the system to treat it as a normal incoming call.

If users don’t want to take any action on unknown calls, they can simply uncheck the ‘Enable Call Filter’ checkbox.