"Android and iOS should have a system-level ability to lock focus on the active application. This would mean you could open a concert ticket, a photo, or your digital insurance record (which is a VERY BAD IDEA to hand to a cop without this feature), guest-lock your phone, and hand it over without any worry that someone could start opening other apps to look for things you didn't want to show them."
> Android and iOS should have a system-level ability to lock focus on the active application.
iOS already has this, it's called Guided Access and you can access it by triple-pressing the power button... it even lets you set up areas of the screen that can't be pressed.
Both Apple and Android have this feature preloaded. On Apple it’s called Guided Access and is three taps of the power button if enabled. On Android I’m not sure but I do know it exists (edit: it’s called App Pinning)
On iOS you can also disable specific actions and even select areas of the screen you want to disable touchscreen usage over.
Guided Access is what I occasionally used when our first child was 2-3 years old and I had to hand him the phone to watch videos with input locked out. It was never an effortless process, it would be awkward to fumble around with before handing my phone to someone. It would make it look like I have something to hide (don't we all?) Maybe I'm doing something wrong.
This feels like a social problem, not a technological one, and I am unconvinced that a technological solution will work here.
If the worry is that the cop you hand your phone to will take more access than you want, then attempting to limit that access is probably not going to work out the way you want.
A more effective solution would be better legal protections.
I had an Android phone circa 2018 (Samsung S8) that had this feature: it was called "App Pinning" and people could only navigate inside the pinned app until you unlocked your phone like you usually would.
Edit: I am now an iOS user since 2022, and I only learn about "Guided Access" from other comments haha
I believe this works on Android in general, but I tried on GrapheneOS. Open the Settings app. Tap Security & Privacy > More security & privacy > App pinning. After that is enabled, if you want to pin an app, open it, swipe up into the recent-apps view, tap the icon of the app above the preview pane, and select "Pin".
The feature is buried a bit. I believe this is because it's more of a best-effort protection. The settings page itself says:
"When an app is pinned, the pinned app may open other apps and personal data may be accessible. If you want to securely share your device with someone, try using a guest user instead."
> This means it would be more easily abused if you're using biometric unlocks, yes, but by no means does it make the feature useless. And it normalizes a level of trust between individuals which is appropriate, but impossible, in many situations.
Here's the problem. By being abusable, it falsly normalises a level of trust. I.e. it deceives the user into trusting it.
App pinning exists on Android already, it's extremely useful if you're handing over your phone to your child to just watch netflix or whatever :P It's just extremely unintuitive, I had to google where it is.
It's the kind of feature that would rub people the wrong way, whether it's a cop, a friend, or a stranger you want to show a funny video to.
To give a couple of examples, using this would be a bit like locking the glove box in front of traffic cops, or going around the house locking rooms when you have a guest.
The only way to make it socially acceptable would be to make it some sort of default (for example, requiring face id when switching apps, with pin/fingerprint as a backup), which will probably be an option as the lag and failure rate of face id or other owner-detection technologies improve.
In the case of cops there's basically no way to interact with them that's both safe and makes them happy. But I just keep a printed version of my insurance for that reason.
in response the all the comments that state that this feature already exists. i didn't know about that, and it's also not the kind of feature that should be obvious so i would not think to search for it, so i am very glad to find this here.
needing this happens rarely and in most cases where i needed it i actually wanted to show a static screen and not even give access to the whole app. for that i found an app that can show an image on an otherwise locked screen.
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[ 2.4 ms ] story [ 13.2 ms ] threadiOS already has this, it's called Guided Access and you can access it by triple-pressing the power button... it even lets you set up areas of the screen that can't be pressed.
https://support.google.com/android/answer/9455138?hl=en
On iOS you can also disable specific actions and even select areas of the screen you want to disable touchscreen usage over.
If the worry is that the cop you hand your phone to will take more access than you want, then attempting to limit that access is probably not going to work out the way you want.
A more effective solution would be better legal protections.
Edit: I am now an iOS user since 2022, and I only learn about "Guided Access" from other comments haha
The feature is buried a bit. I believe this is because it's more of a best-effort protection. The settings page itself says:
"When an app is pinned, the pinned app may open other apps and personal data may be accessible. If you want to securely share your device with someone, try using a guest user instead."
Here's the problem. By being abusable, it falsly normalises a level of trust. I.e. it deceives the user into trusting it.
To give a couple of examples, using this would be a bit like locking the glove box in front of traffic cops, or going around the house locking rooms when you have a guest.
The only way to make it socially acceptable would be to make it some sort of default (for example, requiring face id when switching apps, with pin/fingerprint as a backup), which will probably be an option as the lag and failure rate of face id or other owner-detection technologies improve.
needing this happens rarely and in most cases where i needed it i actually wanted to show a static screen and not even give access to the whole app. for that i found an app that can show an image on an otherwise locked screen.