Fix #389: Low-fi Home fragment implementation 2 (Nested RecyclerView)

[rt4914]

Explanation

This PR implements nested recyclerview to create carousel in HomeFragment.

Mock: https://xd.adobe.com/spec/e2239cf4-9cde-4c08-5296-25316c1f0a14-9412/screen/d47aa8de-a7a8-4d25-b011-5baefc7b7098/HP-Home-Page-

For testing carousel follow these steps:

1. Go to TopicListController.kt file in domain module.
2. In createOngoingStoryList, just repeat ongoingStoryListBuilder.addRecentStory twice, or something similar to that, check screenshot.

Checklist

• The PR title starts with "Fix #bugnum: ", followed by a short, clear summary of the changes. (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• The PR explanation includes the words "Fixes #bugnum: ..." (or "Fixes part of #bugnum" if the PR only partially fixes an issue).
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• The PR is made from a branch that's not called "develop".
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[veena14cs]

It works smoothly. LGTM

[nikitamarysolomanpvt]

LGTM

[BenHenning]

Thanks @rt4914. I have some concerns about the manual margin/padding computations happening. Other than that the changes LGTM.

[BenHenning]

This is a bit hacky and won't work correctly for RTL layouts. Why do we need it?

[rt4914]

Actually as per @mschanteltc suggestions the implementation should be like this,
If there are more than 1 items, then the left and right margin are uneven, so as to make visual room for next item

But if there is only one item, it will become an issue, so in that case, left/right margin should be same on both sides

[BenHenning]

Thanks, that makes sense to me. Could we also solve this by setting end padding on each individual item, but set the start padding on the whole recycler view? My thinking is that the padding/margin probably should be the same for each item, and in the case when there is only one item then ensuring the spacing is correct falls on the container itself.

[rt4914]

We cannot change the padding/margin of recyclerview because all the items in HomeFragment are at a particular margin/padding on left and right but as the promoted story is a carousel, it will use the entire width of screen when learner scrolls, therefore the recyclerview needs to have padding and margin as 0. And the padding/margin should be controlled on items(promoted story) only.

[BenHenning]

Ah. Hmm. I’ll need to think on this to see if there’s a cleaner way to do it. Let’s go with this now.

[rt4914]

Okay.

[BenHenning]

Thanks!