iOS: Link to System Preferences for app permissions when necessary

[chrisbobbe]

iOS has a quirk where an app can only display the native alert requesting a specific permission once. If the user declines, and then they retry the action that requires the permission (and on all subsequent retries), it will fail. Currently, we handle this by displaying, e.g., “Error: photo library permissions not granted.” Instead, let’s provide a button that will navigate to the Zulip page in System Preferences and prompt the user to grant it manually. (I know there’s a way to do this linking, as I’ve done it before, but I can’t remember exactly — I think we can use the Linking API from React Native.)

[jainkuniya]

I think we can use the Linking API from React Native.)

Yes, it will look like:

Linking.openURL('app-settings:')

I am thinking of adding a button (in right hand side, and rename current ok button to cancel) in current alert to open system preferences.

@gnprice @chrisbobbe thoughts?

[gnprice]

I am thinking of adding a button (in right hand side, and rename current ok button to cancel) in current alert to open system preferences.

For the UI: we should do whatever is the standard thing that Apple recommends to do here. So the next step for figuring out the right UI is to find the relevant Apple documentation and see what it says.

[chrisbobbe]

Yes, it will look like:

Linking.openURL('app-settings:')

Ah, it looks like there's a safer way to do it in RN v0.60.0 (#3548), just Linking.openSettings(): facebook/react-native@fa426cf. It's probably not a bad idea to wait for RN v0.60.0 so we know all releases use the safer code, and we expect to be on v0.60.0 soon (EDIT: marking this as "blocked" for that reason).

I am thinking of adding a button (in right hand side, and rename current ok button to cancel) in current alert to open system preferences.

I think a two-button alert, with "Cancel" on the left and "Open Settings" on the right would be in line with the Human Interface Guidelines on Alerts. I wonder if we can produce the alert message itself by programmatically accessing the "usage string" for the particular permission: e.g., NSPhotoLibraryUsageDescription in Info.plist. On the other hand, perhaps we should have a more generic message, so there's a clear path forward for translations.

Apple's doc on requesting access to protected resources doesn't have specific guidance on navigating the user to Settings on access attempts following the first.

[jainkuniya]

facebook/react-native@fa426cf

Cool! wow, they have added support for Android as well. This will fix our Android case as well at the same time.

I think a two-button alert, with "Cancel" on the left and "Open Settings"

Agree 👍

Currently we get

as string in error. We can use this and append Open setting to grant now.

[gnprice]

And that RN upgrade is complete! So we should now be able to do this using that improved support.