# compose

Garret Yoder

03/06/2024, 7:43 PM
Hey guys - looking for some feedback and thoughts on something I spent this morning tweaking. this is a multiplatform implementation for the old style material collapsing app bar w/ enterAlwaysCollapsed. The current M3 toolbar implementation doesn't have support for this, you can do a collapsing app bar but you just pick the size you want. Having a massive LargeAppBar appear on scroll is less than ideal. This implements a lazycolumn w/ a decorator toolbar that is large initially, shrinks to small when scrolled, and hides/shows on scroll. It grows back to the full height when you hit the top. The reason I'm asking for feedback is I feel like it's a little hacky due to me making this multiplatform. I was unable to just mimic natural scrolling like seen here(

). This is because on desktop the nested scroll events can easily have enough velocity that you can never really detect when the list reaches the top in preScroll - only in postScroll. You also can't use the drag event to make it scroll smoothly to the top without stopping line other implementations do. What I opted for was to just animate the toolbar expand when you hit the top of the list, and I think it feels pretty okay. Anyone have any feedback or has done something similar better than I just did?