I stumbled upon this weird LazyColumn+scrolling pr...

# compose

[Emil Lahtinen]

I stumbled upon this weird LazyColumn+scrolling problem which leads to ANR, details in thread

[Emil Lahtinen]

So the problem occurs when trying to scroll focused item to the top of the screen. If you start scrolling the items with arrow keys first downward, then scroll back up ‘past the first row’ it jumps to what seems a random row after which GC goes haywire and causes ANR. This happens (at least, haven’t tested thoroughly) with API 27 but not with API 19

[Emil Lahtinen]

Screenshot from profiler

[Emil Lahtinen]

I created a minified version where the problem occurs: https://github.com/ELIEL87/lazycolumntest

[matvei]

cc @Ralston Da Silva

[Heikki Rauhala]

The minified version also shows strange janky behaviour of animateScrollToItem when moving upwards. It's difficult to tell if that is related to the GC problem. Maybe this should be filed as two distinct bugs?

[Ralston Da Silva]

Sorry for the delayed response. Yes, we are aware of this issue and we are in the process of adding a few low level APIs so that we can support focus traversal in LazyLists

[Walter Berggren]

Thanks for the update, great to hear that it is being worked on 😊