iOS supports this with "Guided Access" mode. It has to be enabled in settings, then a triple click will turn it off/on. It can have its own passcode as well. I use it when handing my phone to my kids--start a video, enable guided access, and not worry about who they might inadvertently call or photo they might delete.
I'd love to be able to map this to ipad side switch (which no more exists) - my kids use it to fix the picture on screen so that they could put a paper over screen, and use the picture as a template for drawing.
No, it's not like that at all. You have to not just enable it but also select inaccessible areas of the screen. Every time. And they get greyed out which makes it unusable for watching videos while disabling inadvertent interactions (accidental pause/resume/rewind etc).
You don’t have to disable any part of the screen. Just hit “start” and you are locked into the app.
I just tested it and the only thing I could not do was change the volume.
You've missed my point completely. I want the _whole damn screen_ disabled so I don't inadvertently press pause/skip forward when watching videos for example. It's exactly the opposite of the behavior you get from "guided access" thing.
I apologize, I misread what you said. In options (bottom left of the screen) there is a switch to disable touch completely (it also seems to remember it’s setting for that particular app).