I have an older Android (Samsung S5) with a physical hover feature - you literally hover your finger close to the screen and it triggers hover actions like previewing a message or opening a magnifier over text. It is called "Air View"[1] in Samsung lingo, and was coupled with other features ("Air Gesture"[2]) involving moving your hand over your phone to do things like scrolling or waking the screen.

It's finicky on occasion, but when you are used to it, it's surprisingly intuitive practical! It wasn't super popular though, and I imagine it could be annoying to users who didn't want it. It appears they only did it for a few models, ending in the S5.

That phone was pretty interesting, sensor-wise. I kind of miss using it, and I wonder if it would be practical nowadays.

[1] Air View: https://www.samsung.com/hk_en/support/mobile-devices/what-is...

[2] Air Gesture: https://www.samsung.com/hk_en/support/mobile-devices/what-is...

Would tap-and-hold be the closest equivalent?

At least that’s how you get tooltips on Android. Of course, tooltips were designed to be discovered by a user hesitating with their mouse over an UI element (sometimes works, sometimes doesn’t), while tap-and-hold on buttons you have to know about, and it’s still scary when the button looks like it could do something potentially destructive and you want to find out.

Long-tap to see tooltips is a convention that has been proposed in various incarnations of the Android UI guidelines. The convention was present in very early Android UI guidelines (e.g. Android 4.x); I'm not sure if it still is.

The problem is that long-tap gets used for a lot of other things on Android (extended selection, particularly). The user experience is pretty unhappy if you use both conventions. And, in practice, long-tap tooltips are so rarely provided on Android apps that I doubt that ordinary users would expect them at all.

As far as I know, tap-and-hold (as distinguished from long-tap) isn't a conventional gesture on Android.