Issue 5835 nearby

[tristan81]

Fixes #5835

Fix for reported bug: Nearby map does not show new pins when moving map a little, especially noticeable when zoomed in

What changes did you make and why?

Modified NearbyParentFragment.java:

• Onscroll - removed distance threshold that was requiring the user to scroll a distance of at least 2000m before a search was initiated. Added logic to delay search by 800ms when OnScroll is fired, mulitple scrolls within 800ms are debounced and only most recent is actioned.

• OnDestroy - destroy any queued OnScroll initiated searches that could be waiting to run when the OnDestroy event is fired.

Tests performed (required)

• Tested main app on virtual device API Level 35

• Ran all automatic tests, same results as unmodified code base.

• Tested Nearby screen on virtual device:
  -- multiple scrolls within 800ms threshold
  -- scroll and wait 800ms for search initiation
  --make successive scrolls within 10 seconds

Test notes:

• Experienced occassional HTTP 500 error but it is coming from the unchanged UpdateMarkers()

Screenshots (for UI changes only)

• no UI changes included

[nicolas-raoul]

Testing now. :-)

[nicolas-raoul]

Working great and the code looks good. Thanks a lot Tristan!

[nicolas-raoul]

Ah, just after merging I notice this issue, pins disappearing/reappearing many times at the beginning of the video, after moving the map once:

screen-20241002-141556.mp4

Any idea what it might be?

[nicolas-raoul]

screen-20241002-142150.mp4

[tristan81]

It wasn't noticeable in my area but I can see it now when I move my position to the nearest city centre where the place markers are dense.

I think I know what is causing it, sub methods that load the places (i.e. populatePlacesForCurrentLocation()) are spawning processes. Forcing them to stop when there is a new OnScroll can leave the UI in an inconsistent state because they are controlling UI features like the progress bar, locking/unlocking the map.

The places are updating in blocks of three, I assume this is so the UI isn't locked for the duration of populating the places which in my closest city can take 10 mins for all the places to load. Instead of querying for all the places in the viewable map area in a single HTTP request it is running many HTTP for each place/attraction which is visible in logcat.

I will need to work out how to get methods like populatePlacesForCurrentLocation to gracefully terminate if stopped before completion.

Should we revert the merge?

[nicolas-raoul]

Better not revert the merge, as it is a clear improvement. :-)
If you have time to send another pull request building upon it, that would be wonderful.

[tristan81]

okay I will see if I can improve it.