refactor(card-browser): Convert to fragment (and fix a few issues)

[david-allison]

Purpose / Description

Requested by @BrayanDSO

Fixes

• Fixes Migrate the Browser into a Fragment #17901

Approach

See commits:

1. Create fragment and move UI elements there
2. define accessors for UI elements via cardBrowserFragment
3. Go through each usage of accessors and move inside fragment
4. finally, remove the cardBrowserFragment, it became test only

---

• fix: maintain selection after selecting flag
• fix: don't show focused row if non-fragmented

How Has This Been Tested?

• Unit tests
• Google Pixel 9 Pro
• API 34 tablet
  • One bug, also present in main : Browse (split screen): changing deck in note editor updates the browser instead #18462

Learning (optional, can help others)

Easier than expected. There's more rounds if we want to tackle the menu

I feel I did something wrong....

Checklist

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[mikehardy]

LGTM and I'd prefer to get this in ASAP so it receives quickest wide testing as possible

One thought regarding possible memory leak - I'll trust your analysis and any possible changes

[mikehardy]

interesting - while doing the review on #18467 I saw a lot of chatter on memory leaks related to the combination of Fragment + RecyclerView + Adapter, and it looks like this may suffer from the leak described

https://stackoverflow.com/a/46957469/9910298

the adapter will continue to live on in the fragment after the RecyclerView goes away, which will leak perhaps?

during the fragment lifecycle (ie. in onDestroyView) the adapter may be set to null and cleared out of the recyclerview to allow it to GC

there's an interaction with the var declaration as lateinit vs nullable though - and maybe I'm mis-reading it and this doesn't apply ? fine with being wrong and this being comment being closeable

[david-allison]

Not enough motivation to deep dive today. May not have been a problem due to the lifecycles of the activity and fragment being equal.

Fixed:

    override fun onDestroyView() {
        super.onDestroyView()
        if (::cardsListView.isInitialized) {
            cardsListView.adapter = null
        }
    }

[BrayanDSO]

Mike's comment was addressed, and we can keep looking if it causes other leaks after the merge