Improve offline map download user experience

[cafootitt]

Moved the remaining bug from #9 into new issue.

Just one thing I noticed about how the maps are downloaded (steps below):

• Logged in as demo user
• Available maps to download were SOANIERANA IVONGO and MANANARA AVARATRA
• I selected both maps and tapped on Download button
• SOANIERANA IVONGO downloaded quite quickly and disappeared
• MANANARA AVARATRA took longer to download, but I noticed that it disappeared from the list after it started downloading; whereas with SOANIERANA IVONGO, the location showed in the list while it was downloading.
• When MANANARA AVARATRA reached about 93% download, the downloading status disappeared, yet the location didn't appear in the DOWNLOADED tab for several minutes. So there's basically a period of several minutes where the user isn't sure whether the download worked because the snack bar message with the download percentage disappeared, and the location name disappeared in both tabs.
• Apart from this small point of possible confusion for the user, the download works really well!

[cafootitt]

@bennsimon To share a new apk to test a proposed fix for this.

[cafootitt]

Benn to share an apk to test this.

[cafootitt]

QA 8 Feb 2021:

I don't think the user experience has gotten any better. I tried to download the "TAOLAGNARO" map and it showed a toaster message up until about 0.17% download, and then the toaster disappeared. After some time, the map appeared in the downloaded section, but I'm not clear if it was actually downloaded, because it says "downloaded null". See below. I think I briefly saw a toaster that started with "HTTP..." and it must have been an error message, but it disappeared before I could take a screenshot. When I try to delete this map and tap on the Delete button, there's no visible response.

I also tried to download "MANANARA AVARATRA" but it failed to download. I saw the toaster to say it started to download, but nothing happened after that.

[cafootitt]

Potential solutions to the huge district download issue:

• Download sections of the district instead of the whole district (ie. user selects Communes instead or downloads areas around the service points themselves, but this latter option is a much larger LOE)
• Zoom level for offline maps is min 5 and max 11, which sounds reasonable (if we reduce the max zoom level, it will affect the clarity)
• Mapbox issue that limits the number of tiles, so we could increase that amount. See how many tiles are in that specific district

[cafootitt]

16 feb 2021 release - Reduced max zoom level to 10

[cafootitt]

Closing in favor of this new issue: #56