Hey guys, pretty broad question - assuming that I create my own CustomTheme (<https://developer.andr...

# compose

[scana]

Hey guys, pretty broad question - assuming that I create my own CustomTheme (https://developer.android.com/jetpack/compose/themes/custom), how can I share it efficiently between screens, given that I migrate existing XML Fragment-based app to Compose?

E.g. I migrate two separate screens to Compose, and they both are built like this:

CustomTheme {
   // screen A content
}

CustomTheme {
  // screen B content
}

Won't this recreate my fonts/colors all over again? What would be the best approach here?

[f.babic]

you could store/prepare the fonts/colors etc in your AppClass and then have your themes pull from a singular place so that it's not recreated every single time

[scana]

This was actually my first approach as I kept all of typography styles and colors as static fields, but it seems that CompositionLocalProvider would be a better approach to e.g. share dark mode colors

[scana]

But yeah, I'll try with just initialising fonts/colors set once and reusing it

[f.babic]

Yeah you can use composition locals to provide some values, but you'd need to check if you already set the values or not, so you don't override them

[Filip Wiesner]

Is this really a problem tho? The way you are doing it now looks fine to me 🤷

[scana]

Design system at my company is a custom one and doesn't really follows material design practices. It is pretty big and I was wondering whether I could avoid re-creating tons of resources every time a screen is opened. But obviously forgot about the simplest solution 🤦

[Chris Sinco [G]]

Won’t this recreate my fonts/colors all over again? What would be the best approach here?

If you follow the guide, you essentially would just redo the MaterialTheme solution with your own colors/typography/shape. The values of that get passed down to all hierarchies via CompositionLocals. There shouldn’t be any overhead to resources being recreated. You just wrap the UIs you need with CustomTheme which would all be derived from wherever you declare that information, e.g. ui.theme.CustomTheme.kt

[Chris Sinco [G]]

If you haven’t already, I’d suggest looking at the Jetsnack sample that has a non-Material custom design system: https://github.com/android/compose-samples/tree/main/Jetsnack

[Chris Sinco [G]]

Most folks just copy that implementation and add/change values as needed by their specific design system

[Chris Sinco [G]]

Though you did mention XML Fragments - if you must share XML resources with your Compose theme, this adapter can be helpful: https://github.com/material-components/material-components-android-compose-theme-adapter