Unusable or Undebuggable? Rebelling against "best practices"

Who is your speaker His name is: Louis CAD • Developed for Android since 2014 • Wears smartwatches since 2015 (Android Wear / Wear OS) • Kotlin lover since 2016 • Does open source since 2016 with Splitties, and other projects • Currently focused on Charts-kt by Data2Viz, a commercial Kotlin Multiplatform charting library (JS, iOS, JVM, & Android of course) • Also doing Wear OS apps, and contributing to OSS projects

LazyColumn & basic features The truth that hurts

No content

More than 3 years old 💀

@Louis_CAD Component: ScalingLazyColumn

@Louis_CAD Component: ScalingLazyColumn .com/android/wear-os-samples/issues/238 Jank and poor scrolling performance on the ComposeAdvanced sample

@Louis_CAD Reproduced on 3 watches (Samsung, Mobvoi, Google) Unreproducible on the emulator… Component: ScalingLazyColumn .com/android/wear-os-samples/issues/238 Jank and poor scrolling performance on the ComposeAdvanced sample

@Louis_CAD Reported in 2022 (12th March) Reproduced on 3 watches (Samsung, Mobvoi, Google) Unreproducible on the emulator… Component: ScalingLazyColumn .com/android/wear-os-samples/issues/238 Jank and poor scrolling performance on the ComposeAdvanced sample

@Louis_CAD Reported in 2022 (12th March) Reproduced on 3 watches (Samsung, Mobvoi, Google) Unreproducible on the emulator… Component: ScalingLazyColumn "Closed as completed" within 4 days! 🎉⁉ .com/android/wear-os-samples/issues/238 Jank and poor scrolling performance on the ComposeAdvanced sample

@Louis_CAD Reported in 2022 (12th March) Reproduced on 3 watches (Samsung, Mobvoi, Google) Unreproducible on the emulator… Component: ScalingLazyColumn "Closed as completed" within 4 days! 🎉⁉ .com/android/wear-os-samples/issues/238 Jank and poor scrolling performance on the ComposeAdvanced sample

Conclusion

Conclusion • Don't debug your app on an actual watch? • Enjoy the ergonomics of manipulating a watch emulator with a mouse pointer! • release build: really slower than debug build? (yes)

Conclusion, 2 option sets: 1. Unusable or Undebuggable 2. Kinda usable and debuggable

Conclusion, 3 option sets: 1. Unusable or Undebuggable 2. Kinda usable and debuggable 3. Hack around

Hack around

In the mind of a rebel about to hack around Back in 2015 (7-8 years ago), scrolling was smooth on my LG G Watch It doesn't have to be! 
 People need to know. People say RecyclerView is verbose I don't remember RecyclerView being laggy LazyColumn lagging behind RecyclerView? 
 Déjà vu Insertions and removals animations? I wrapped RecyclerView to get them Let's try that thing again?

Let's try that thing again?

Let's try that thing again? Let's take a step back f irst.

@Louis_CAD LazyColumn RecyclerView Simple, high-level API, out of the box 👌 Ok-ish/poor performance in debug mode 😕 @Louis_CAD No insertion/removal animations 😭 Lower-level API, complex by default 🫤 As smooth as its content 🤞 Animates all item changes, by default 😎 Scrolling friction on Samsung GW4 😓 Keeps all user input ✅

What if LazyColumn was using RecyclerView under the hood? I heard SwiftUI kinda does that on iOS: Using UITableView for LazyVStack & LazyHStack.

@Louis_CAD LazyColumn RecyclerView Simple, high-level API, out of the box 👌 Ok-ish/poor performance in debug mode 😕 @Louis_CAD No insertion/removal animations 😭 Lower-level API, complex by default 🫤 As smooth as its content 🤞 Animates all item changes, by default 😎 Scrolling friction on Samsung GW4 😓 Keeps all user input ✅

@Louis_CAD LazyColumnWithRecyclerView Simple, high-level API, out of the box 👌 Ok-ish/poor performance in debug mode 😕 @Louis_CAD No insertion/removal animations 😭 Lower-level API, complex by default 🫤 As smooth as its content* 🤞 Animates all item changes, by default 😎 Scrolling friction on Samsung GW4 😓 Keeps all user input ✅

@Louis_CAD LazyColumnWithRecyclerView Simple, high-level API, out of the box 👌 @Louis_CAD As smooth as its content* 🤞 Animates all item changes, by default 😎 Keeps all user input ✅ Let's look at that, top to bottom.

@Louis_CAD LazyColumnWithRecyclerView Simple, high-level API, out of the box 👌 @Louis_CAD Let's look at that, top to bottom.

@Louis_CAD LazyColumnWithRecyclerView Simple, high-level API, out of the box 👌 @Louis_CAD As smooth as its content* 🤞 Animates all item changes, by default 😎 Keeps all user input ✅ *Some of the lag is caused by missing pro fi le for Composable content… 
 …so we only made the issue less bad… 😶 
 Scrolling the app a bit gets JIT to fi x the issue, until next deploy. 
 Better than nothing!

Where is the code today? .com/LouisCAD/Splitties