I just tried an app with a LazyColumn on a device ...

# compose

[Pawel]

I just tried an app with a LazyColumn on a device and it is really laggy. Its a small example app with hardly any code in it. I would still expect better performance. I think doing a release build helps a bit. Any suggestions of what else could be affecting performance ?

[Sergey Y.]

It is fast only in release mode with R8 minimizations applied. Alternatively, you can force full AOT on your device to make it run even faster.
I tested LazyColumn with arbitrary length text elements on my Nexus 5 (2013). In different modes, it works very differently, you should not judge raw debug builds.

[Sergey Y.]

raw debug build, no R8 - JIT is running, it is very slow

[Sergey Y.]

release build + R8 minifications applied - much better, but JIT is still there

[Sergey Y.]

release build + R8 + full AOT - you can see the difference

[Sergey Y.]

you can trigger full AOT by running adb shell cmd package compile -r bg-dexopt your_pkg_name right after you installed your app.

[Pawel]

Thanks @Sergey Y. I did test the release build with R8 enabled it was a bit better but still a bit jerky it wasn't as good as as recycler view. I will test it now with full AOT

[Sergey Y.]

if even after all the optimizations there are performance problems, then most likely the problem is in the application code, you need to profile and look for the cause.

[Sergey Y.]

As you can see, JP Compose can work well on hardware that is 8 years old.

[Sergey Y.]

Alternatively you can test the Tivi app, it is also written in Compose.
Source code: https://github.com/chrisbanes/tivi
Google Play: https://play.google.com/store/apps/details?id=app.tivi

[Scott Kruse]

@dan.the.man