LimitOffsetPagingSource loads partial initial page when near bottom of the list causing ui jump [389729367]

Fixed

Bug

Status Update

No update yet.

Description

ev...@tatarka.me

created issue #1

Jan 13, 2025 10:17PM

Component used: room, room-paging Version used: 2.7.0-alpha12 Devices/Android versions reproduced on: emulator

Steps to reproduce:

Scroll to the end of the list. Then preform a refresh that reduces the number of items in the database but keeps the last items that are visible.
Note the ui jumps up several items. This is is because the first load is smaller than the screen size.

This appears to be caused by the logic in https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:room/room-paging/src/commonMain/kotlin/androidx/room/paging/util/RoomPagingUtil.kt;drc=6d0e4120b9ea66164e1f3c1d93e711fac2aed847;l=76 specifically, if the refresh key lands within the last page it'll load fewer items than expected.

Changing

if (key >= itemCount) {
    maxOf(0, itemCount - params.loadSize)
} else {
    key
}

if (key >= itemCount - params.loadSize) {
    maxOf(0, itemCount - params.loadSize)
} else {
    key
}

should fix it.

Comments

da...@google.com <da...@google.com> Jan 15, 2025 05:25PM

Reassigned to da...@google.com.

ap...@google.com <ap...@google.com> #2Jan 15, 2025 07:49PM

Marked as fixed.

Project: platform/frameworks/support
Branch: androidx-master-dev

commit b90079595f33f58fece04026a97faa0d243acdb1
Author: Yuichi Araki <yaraki@google.com>
Date: Wed Sep 18 16:55:49 2019

Change the way to detect mismatch between POJO and query

This fixes cursor mismatch warnings with expandProjection.

Bug: 140759491
Test: QueryMethodProcessorTest
Change-Id: I7659002e5e0d1ef60fc1af2a625c0c36da0664d8

M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/solver/TypeAdapterStore.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt
M room/compiler/src/test/kotlin/androidx/room/processor/QueryMethodProcessorTest.kt
M room/compiler/src/test/kotlin/androidx/room/testing/TestProcessor.kt

https://android-review.googlesource.com/1123258

https://goto.google.com/android-sha1/b90079595f33f58fece04026a97faa0d243acdb1

na...@google.com <na...@google.com> #3Jan 29, 2025 06:11PM

The following changes were cherrypicked through Coastguard (

https://android-build.googleplex.com/coastguard/)
Release Track: (

https://android-build.googleplex.com/coastguard/dashboard/6093116828680192/#/cherrypickHistory/all)
Created: 2019-10-14 17:23:42.610596+00:00
Changes: aosp/1123258

Issue 389729367

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Comments

da...@google.com <da...@google.com> Jan 15, 2025 05:25PM

ap...@google.com <ap...@google.com> #2Jan 15, 2025 07:49PM

na...@google.com <na...@google.com> #3Jan 29, 2025 06:11PM

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