Incompatibility warning card on main screen (COMMUNITY)

[fynngodau]

As discussed in #688 (comment), this PR introduces a warning card on the main screen that informs users when their device is incompatible or only partially compatible with Exposure Notifications.

Screenshots

1: BLE broadcasts not supported	2: BLE scans not supported

To test

• On most devices: open app's main screen. Nothing changes with this PR.
• Use a device that doesn't support broadcasting beacons. Open app's main screen. New card like in screenshot 1. (For example, some operating systems for Fairphone 2 have a Bluetooth driver that doesn't support BLE peripheral mode, see also No beacons sent on Fairphone 2 (Fairphone OS 19.11.2 / Android 7.1.2) #780. Note that I don't own such a device)
• Use Android emulator. Open app's main screen. New card like in screenshot 2. (Android emulator doesn't support Bluetooth at all)

What this PR doesn't do, but should still be done

• Add some further information to the app or to the FAQ or another website that can be displayed once the warning card is clicked.
• Block sharing test results if BLE broadcasts are not supported.

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Internal Tracking ID: EXPOSUREAPP-5464

[Diapolo]

I own a FP2 and use it with CWA (and microG). As far as I can tell I can send and receive beacons, microG is showing me collected IDs and a changing own ID.

[fynngodau]

If microg is not showing a very similar warning text to one of the screenshots within its EN settings, this PR would not display any as well, because the code for detecting incompatible devices is actually the same.

@Diapolo Is microg not displaying such a warning? Which operating system have you installed on your Fairphone 2?

[Diapolo]

I'm using LineageOS for microG 17.1 for FP2, while my girlfriend is still using LineageOS 16 with GAPPS and both versions are able to communicate with eachother via EN beacons.

[thomasaugsten]

@Diapolo is the microgG settings giving some warnings?
@fynngodau can you double check if the check is valid for the FP2 phones?

[fynngodau]

To our knowledge there is a driver issue with Fairphone 2 that prevents BLE from working, it is not a hardware limitation. For this reason, it is possible that an OS for this device exists which ships with a driver that implements BLE broadcasting appropriately.

The LineageOS that @Diapolo installed on their device could contain such a driver. If it does, and the device is broadcasting IDs, and if microG is (hence correctly) not showing a warning, then this PR will also not display a warning.

Our latest information is that the stock ROM (though this information could be outdated and there could be a fix in newer versions) doesn't have such a driver, and we heard from users who are correctly seeing the warning and would also see them in CWA with this PR.

[Diapolo]

@Diapolo is the microgG settings giving some warnings?

No there is NO warnings shown and everything EN-related seems to work fine...

[dsarkar]

Internal Tracking ID: EXPOSUREAPP-5464

[doak]

Don't know it it is eventually the same code, but you can also use the nrf Connect application to detect if "peripheral mode" is working.

More important, you can check if you actually receive BLE beacons from the other device (which proofs that that device is able to send).

[Diapolo]

This is my device and it shows "Peripheral mode supported" YES.

[fynngodau]

Thanks for the interesting information @Diapolo, I'll remember that LineageOS for Fairphone 2 supports BLE broadcasting and forward this information to users in case it is needed. I'll also change the PR's description accordingly to avoid confusion (as well as our FAQ).

[vaubaehn]

Just for additional information/reference, and to support @fynngodau findings: No BLE beacons sent on FP2 with Fairphone OS 19.11.2 / Android 7.1.2, as reported here: #780 (comment)
Edit: I overlooked that @fynngodau already referenced that FP2 in his first comment of this PR.

[vaubaehn]

Great to see that you consider to implement the proposed solution for release 2.1! 🎉

[harambasicluka]

@fynngodau also haven't forgotten that one :) But the same applies as here: #2702 (comment)

[d4rken]

As this PR didn't make it into 1.15.x, it fell a bit behind, I rebased your commits and got it up to speed so that it should make the schedule for 2.2.x.

Closing in favor of #2873