How to use Android-L preview Task Locking?

Question

Has anyone got task locking working in Android L? Could they share some details on how it works? I have seen the instructions below, but struggling to understand this.

Answer 1

Make a file device_owner.xml using below content, replace appropriate package name

adb push device_owner.xml /data/system/device_owner.xml Reboot device.

from com.your.packagename app call

startLockTask(); 

from your activity

Even if you do not have userdebug, you can test it by calling startLockTask, without pushing any file