Add support for comment replies

[Stypox]

What is it?

• Bugfix (user facing)
• Feature (user facing)
• Codebase improvement (dev facing)
• Meta improvement to the project (dev facing)

Description of the changes in your PR

The most basic implementation of comment replies. The replies are shown in a fragment opened from the main activity, instead of on top of the video detail fragment. Although this might be a bit unexpected, this can be improved later, since I tried and found it too cumbersome to open fragments on top of each other*.

* Yet another broken thing in the current app architecture: opening new fragments from within one fragment. With the old Android APIs it would take something like 100 lines of code spread across many files, since you would have to create a stack of fragments in the base activity, then implement proper state saving in the stack, then push and pop items from the stack in the correct way, ... If we used the modern APIs instead, after the initial setup in the topmost activity, it would be as simple as writing something along the lines of findNavController(...).navigate(viewId, arguments).

Implementation notes

• I removed the comment mini variant since it was never used. Now only one variant exists, which reduced code duplication and made it simpler to edit the layout to add the replies button.
• The comment item layout had a few changes (other than adding the replies button) that fixed RTL warnings.
• I moved RelatedItemsInfo in the same folder as RelatedItemsFragment, since it wouldn't make sense for that class to stay in util. I also simplified the code in that class. Although this is an unrelated change, I did it because I also added CommentRepliesInfo that works in a similar way, and put it in the same folder as CommentRepliesFragment.
• At first I though that to load comment replies the extractor needed the original CommentsInfo object, so I made bb01da3, but then I found out that the url is enough, so I reverted that change in 50a3ae6.
• The replies page has at the top the starting comment of which replies are shown. The text size there is a bit larger than for comment items, and the comment content is always expanded.
• The only code smell reported by Sonar is about CommentInfoItemHolder.updateFromItem, but I would ignore this warning since I already simplified many parts of that method in 8bd42d9 and added comments to separate the various actions being performed.

Before/After Screenshots/Screen Record

Before	Video details page	Replies page	With heart and pin

^{Note to blog post writers: I just noticed these images contain some aggressive comments in Italian, so they need to be taken again}

Fixes the following issue(s)

• Closes Display comment replies #2277
• Fixes SoundCloud large playlist can’t load #10012 thanks to e236d37, also see [SoundCloud] Fix certain playlists showing as empty NewPipeExtractor#1049

APK testing

The APK can be found by going to the "Checks" tab below the title. On the left pane, click on "CI", scroll down to "artifacts" and click "app" to download the zip file which contains the debug APK of this PR.

This PeerTube video has nested replies, but they don't seem to work: https://share.tube/w/vxu4uTstUBAUromWwXGHrq.

Due diligence

• I read the contribution guidelines.

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Notes for the website team: make sure to modify the corresponding FAQ entry when updating the page for the release.

[tsiflimagas]

It works good and pagination works well too, I can load 500 comments. Though, I think that "List view mode" shouldn't affect the way comments are displayed (grid view for comments doesn't look well). Probably I'm ignoring that's an impact of how the fragment is opened, but idk the technical stuff.

[Stypox]

I think that "List view mode" shouldn't affect the way comments are displayed

Thank you for noticing, now it's fixed :-)

The PR should now be ready

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
1 Code Smell

0.0% Coverage
0.0% Duplication

[Stypox]

@TobiGr this PeerTube video has nested replies, but they don't seem to be returned by the extractor: https://share.tube/w/vxu4uTstUBAUromWwXGHrq.

[nicoursi]

This is nice but there's a behaviour I think should be fixed: when comment replies are open, the android back button should just close the replies and not get back to the last video list.

[Stypox]

That's an inconsistent behavior that is independent of this PR and is definitely strange. According to @opusforlife2 in Android the expected behavior for the top-left back button is to go to home, while the system back button should go to the previous fragment. This can be fixed in a separate PR.

[opusforlife2]

aggressive comments in Italian

xD

According to opus

Not me! I was just quoting!

[TobiGr]

@TobiGr this PeerTube video has nested replies, but they don't seem to be returned by the extractor: https://share.tube/w/vxu4uTstUBAUromWwXGHrq.

See TeamNewPipe/NewPipeExtractor#1052

[MD77MD]

i think the approach in [Show comment replies #9410] by @xz-dev is much better because:

1. it does not take us to a new page
2. if we scroll down throw comments and finish reading a reply, going back will always take me to the top of the comments page then we need to scroll back to where we were.
3. and most important, it open replies in an expandable/ retractable list that doesn't cut our flow off reading

[Stypox]

@MD77MD yes, if only it didn't have strange scrolling bugs and object cloning. I have already explained why this choice is being made.

[MD77MD]

i hpoe this is not taken the wrong way, but this feature is implemented in another fork called pipepipe. perhaps you guys can take a look and see if they have managed to solve the scrolling problem stypox mentioned, or even improve on top of it in later updates. the link is down below

https://github.com/InfinityLoop1308/PipePipe

[TobiGr]

Annotations are missing. Once added, this can be merged

[Stypox]

I think your commit does not provide a proper behaviour:

• pressing the system back button correctly closes the replies fragment and brings you back to the video
• pressing the back arrow at the top left of the screen does not close the replies fragment
• when there are nested replies, going back correctly closes only the top fragment, but the video is always brought up even if you were looking at the replies of a nested comment, which is unexpected imo (you can test with the URL in the PR description)

[TobiGr]

I fixed the behaviour you pointed out above.

One thing that I noticed is that the DetailFragment is scrolled to top after it is expanded from the BottomSheetBehaviour. I pushed a second commit which should help us to scroll to the last clicked comment. However, when calling CommentsFragment.scrollToComment nothing happens. Any ideas why?

[sonarcloud]

Quality Gate passed

The SonarCloud Quality Gate passed, but some issues were introduced.

2 New issues
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[Stypox]

I rebased, fixed various problems with going back from the replies fragment to the video details fragment, and added the @NonNull annotation as requested by @TobiGr's review. If nobody has anything against it, I will merge this PR as it is now. I might try to open another PR soon that implements PipePipe's behavior: #10018 (comment).