Hide app content when app is in background

[sosnovsky]

details - https://github.com/FlowCrypt/flowcrypt-security/issues/264

[DenBond7]

@sosnovsky I can add

window.setFlags(
            WindowManager.LayoutParams.FLAG_SECURE,
            WindowManager.LayoutParams.FLAG_SECURE
)

But this will disable making screenshots too. Do we need the ability to make screenshots in the app?

[DenBond7]

For history. ref https://issuetracker.google.com/issues/237190495

[sosnovsky]

Yes, I think taking screenshots should still be allowed in the app. Maybe it's possible to apply this flag only when app is in background, like described here - https://stackoverflow.com/a/49442984/3091318 ?

[sosnovsky]

Also there is setRecentsScreenshotEnabled property added in Android 12, we can use it for Android 12+, and View#onWindowFocusChanged(boolean) for older versions. What do you think, will it work?

[DenBond7]

Yes, I think taking screenshots should still be allowed in the app. Maybe it's possible to apply this flag only when app is in background, like described here - https://stackoverflow.com/a/49442984/3091318 ?

Yes, it's possible. Also, need to add that starting from Android 12 we have a little different behavior. Please look at the example

Content will be hidden after switching to other apps. (At this stage the app will have a paused state)

[sosnovsky]

Looks good 👍