fix: Scroll and restore position correctly in Home and Notifications #1240
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These are cached timelines, backed by Room. Room **requires** the `PagingConfig` to have `enablePlaceholders = true`. Otherwise the list is corrupted when scrolling down the list and paging in new items. To restore the user's reading position correctly in the UI, wait for the adapter to emit the very first page. Combine this with the user's refresh key, and the number of placeholders in the page, to scroll the user to the correct place in the list. To make all this work, ensure that Room loads a large enough page of data around the refresh key (in the `initialKey` calculation).
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These are cached timelines, backed by Room. Room requires the
PagingConfigto haveenablePlaceholders = true. Otherwise the list is corrupted when scrolling down the list and paging in new items.To restore the user's reading position correctly in the UI, wait for the adapter to emit the very first page. Combine this with the user's refresh key, and the number of placeholders in the page, to scroll the user to the correct place in the list.
To make all this work, ensure that Room loads a large enough page of data around the refresh key (in the
initialKeycalculation).