Programmatically restrict user access to Android/iPad/iPhone device while an app is in a certain state

Some background information:

I currently sell a niche software product for Windows PCs. Some of my clients are expressing heavy interest in rolling out similar functionality to their Android and iPad users. I am not an Android or iOS developer. My software solution restricts user access to a computer by disabling the screen while some specific hardware is giving a certain signal.

The essence of my question:

Is开发者_开发问答 is possible, on either Android or iOS, to programmatically restrict access to the device while an app is in a certain state.

This could involve any of the following:

1. Preventing the user from changing apps or returning to the home screen while the app is in a certain state.
2. Locking the screen while the app is in a certain state.
3. Turning the screen off (or completely disabling the screen) while the app is in a certain state.

I imagine this isn't something "normal" apps could do - the malware implications are quite horrible. For my purposes, it is acceptable if some certain administration actions or special install steps are taken.

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For regular (I will later decode meaning of word regular) Android device it's impossible, since always there's a possibility for end-user press magic button "HOME" and you can access to any device features. HOME button can't be intercepted by any application - it's low-level restriction.

Under regular I mean Android device with standard kernel. But there's a possibility to hack kernel and rewrite those restriction related to HOME button, for sure after that you'll be solely responsible for all kind of support, update and so on.

About iPhone: it's not my field - I don't know.