Locking android device from app -

please me in how lock android device app.

devicepolicymanager devicepolicymanager = (devicepolicymanager) getsystemservice(context.device_policy_service);  devicepolicymanager.locknow();

used above code not working.

before lock screen need enable admin permission.you can check whether device admin active or not like

devicemanger.isadminactive(compname);

if not have enable first, , can lock device using

devicemanger.locknow();

for further information can refer this:

Detect