1) This type of app doesn't work on some phones. I don't have a Note 4, but that may be one of the phones it doesn't work on.
2)
Tasker, with the
Secure Settings plugin can control the lock screen, and
Tasker App Factory can turn a task into an app you can put on the homescreen (or probably run from the lockscreen). Tasker is $3, but considering what you can do with it, it's extremely cheap. (The plugins are free.) My screen is totally unlocked when I'm home - press the power button and I'm on the homescreen. When I leave home, it has a passworded lock screen, USB debugging is off, mobile data is on, etc., etc. All I have to do is drive down he block - Tasker does all the rest. (There's a learning curve, but it's
much easier than learning to write Android apps. And I say this as someone who could write a Windows accounting package in his sleep. I still don't know the Android environment well enough to write Android apps, but I have a whole slew of Tasker apps.)
@Bosbaouer:
That's too simple.