chinwag-android/app
Nik Clayton 9cf4882f41
Keep scroll position when loading missing statuses (#3000)
* Change "Load more" to load oldest statuses first in home timeline

Previous behaviour loaded missing statuses by using "since_id" and "max_id".
This loads the most recent N statuses, looking backwards from "max_id".

Change to load the oldest statuses first, assuming the user is scrolling
up through the timeline and will want to load statuses in reverse
chronological order.

* Scroll to the bottom of new entries added by "Load more"

- Remember the position of the "Load more" placeholder
- Check the position of inserted entries
- If they match, scroll to the bottom

* Change "Load more" to load oldest statuses first in home timeline

Previous behaviour loaded missing statuses by using "since_id" and "max_id".
This loads the most recent N statuses, looking backwards from "max_id".

Change to load the oldest statuses first, assuming the user is scrolling
up through the timeline and will want to load statuses in reverse
chronological order.

* Scroll to the bottom of new entries added by "Load more"

- Remember the position of the "Load more" placeholder
- Check the position of inserted entries
- If they match, scroll to the bottom

* Ensure the user can't have two simultaneous "Load more" coroutines

Having two simultanous coroutines would break the calculation used to figure
out which item in the list to scroll to after a "Load more" in the timeline.

Do this by:

- Creating a TimelineUiState and associated flow that tracks the "Load more"
  state
- Updating this in the (Cached|Network)TimelineViewModel
- Listening for changes to it in TimelineFragment, and notifying the adapter
- The adapter will disable any placeholder views while "Load more" is active

* Revert changes that loaded the oldest statuses instead of the newest

* Be more robust about locating the status to scroll to

Weirdness with the PagingData library meant that positionStart could still be
wrong after "Load more" was clicked.

Instead, remember the position of the "Load more" item and the ID of the
status immediately after it.

When new items are added, search for the remembered status at the position of
the "Load more" item. This is quick, testing at most LOAD_AT_ONCE items in
the adapter.

If the remembered status is not visible on screen then scroll to it.

* Lint

* Add a preference to specify the reading order

Default behaviour (oldest first) is for "load more" to load statuses and
stay at the oldest of the new statuses.

Alternative behaviour (if the user is reading from top to bottom) is to
stay at the newest of the new statuses.

* Move ReadingOrder enum construction logic in to the enum

* Jump to top if swipe/refresh while preferring newest-first order

* Show a circular progress spinner during "Load more" operations

Remove a dedicated view, and use an icon on the button instead.

Adjust the placeholder attributes and styles accordingly.

* Remove the "loadMoreActive" property

Complicates the code and doesn't really achieve the desired effect. If the
user wants to tap multiple "Load more" buttons they can.

* Update comments in TimelineFragment

* Respect the user's reading order preference if it changes

* Add developer tools

This is for functionality that makes it easier for developers to interact
with the app, or get it in to a known-state.

These features are for use by users, so are only visible in debug builds.

* Adjust how content is loaded based on preferred reading order

- Add the readingOrder to TimelineViewModel so derived classes can use it.
- Update the homeTimeline API to support the `minId` parameter and update
  calls in NetworkTimelineViewModel

In CachedTimelineViewModel:
- Set the bounds of the load to be the status IDs on either side of the
  placeholder ID (update TimelineDao with a new query for this)
- Load statuses using either minId or sinceId depending on the reading order
- Is there was no overlap then insert the new placeholder at the start/end
  of the list depending on reading order

* Lint

* Rename unused dialog parameter to _

* Update API arguments in tests

* Simplify ReadingOrder preference handling

* Fix bug with Placeholder and the "expanded" property

If a status is a Placeholder the "expanded" propery is used to indicate
whether or not it is loading.

replaceStatusRange() set this property based on the old value, and the user's
alwaysOpenSpoiler preference setting.

This shouldn't have been used if the status is a Placeholder, as it can lead
to incorrect loading states.

Fix this.

While I'm here, introduce an explicit computed property for whether a
TimelineStatusEntity is a placeholder, and use that for code clarity.

* Set the "Load more" button background to transparent

* Fix typo.

* Inline spec, update comment

* Revert 1480c6aa3ac5c0c2d362fb271f47ea2259ab14e2

Turns out the behaviour is not desired.

* Remove unnecessary Log call

* Extract function

* Change default to newest first
2023-01-13 19:26:24 +01:00
..
schemas/com.keylesspalace.tusky.db.AppDatabase add 46.json (#3116) 2022-12-29 19:29:33 +01:00
src Keep scroll position when loading missing statuses (#3000) 2023-01-13 19:26:24 +01:00
.gitignore
build.gradle Remove old opt-in for RequiresOptIn (#3167) 2023-01-12 19:41:35 +01:00
proguard-rules.pro add shrinker rules to keep bouncycastle EC classes (#2542) 2022-05-19 07:19:16 +02:00