Device Owner Turtorial

Hi, i tried so set the device owner for your extension via adb. But i can't bring it to work. I tried:

`adb shell dpm set-device-owner eu.bubu1.privext/.org.fdroid.DeviceAdminReceiver

adb shell dpm set-device-owner eu.bubu1.privext/.DeviceAdminReceiver

adb shell dpm set-device-owner eu.bubu1.privext `

everything brings an Error. Unknown admin or Invalid component

I also write an device_owner.xml an put it into /data/system with this:

<?xml version="1.0" encoding="utf-8" standalone="yes" ?> <device-owner package="eu.bubu1.privext" name="org.fdroid.fdroid.privileged.PrivilegedService" />

Also not working. Do you have an idea what was wrong?