Minor performance improvement

[GuhDoy]

I think this would improve performance at some points while not significantly increasing the complexity of the code. Could you please review my PR? Thanks!

[GuhDoy]

Well, I suddenly come up with another idea, which is more capable and simpler.

[nanihadesuka]

@GuhDoy thanks for trying improving it but I think current implementation has better UI stability.

Will keep open for a week in case you find a good counter argument 😄

[GuhDoy]

I don't think the recomposition you mentioned is possible. I wrote the following shit code to detect the recomposition behavior you mentioned:

        coroutineScope.launch {
            listState.scrollToItem(index = index, scrollOffset = 0)
            val offset = realFirstVisibleItem
                ?.size
                ?.let { it.toFloat() * remainder }
                ?: 0f
            Thread.sleep(100) // Sleep for 0.1 seconds to pretend we're doing something costly.
            val realFirstVisibleItem2 = listState.layoutInfo.visibleItemsInfo.firstOrNull {
                it.index == index
            }
            if (realFirstVisibleItem2 !== realFirstVisibleItem || realFirstVisibleItem2!!.offset != 0) {
                Log.e("TAG", "recomposition") // <-- Log goes here!
            }
            listState.scrollBy(offset)
        }

The log will only be printed when scrolling to the bottom of the LazyColumn.

[nanihadesuka]

@GuhDoy ok, tested in real device. Seems there are no apparent issues and test pass. Accepted