Why do need to call `setContent(Recomposer.current()) {}` in fragments? and if we must pass a Recomp...

# compose

[andylamax]

Why do need to call setContent(Recomposer.current()) {} in fragments? and if we must pass a Recomposer as a parameter, in which scenario would I need to pass another Recomposer? say setContent(Recomposer.new()){} . If not, why is Recomposer.current() not a default parameter value in setContent?

[Adam Powell]

It's part of moving away from Recomposer.current() altogether and reworking a bit of how creating a composition works in general. Recomposer.current() will be deprecated sometime in the future.

[Adam Powell]

We're probably going to remove the ViewGroup.setContent extension altogether in favor of some sort of public AbstractComposeView that accepts a composable function as a required constructor parameter

[Adam Powell]

Since the current extension has to create one anyway, and today it's just an added layer of view hierarchy

[Adam Powell]

That will pave the way for both a concrete ComposeView that would have a public setContent function, plus it could be a subclass for generated view subclasses from single composables

[Adam Powell]

And we can do the recomposer wire-up a bit differently there

[Adam Powell]

More concretely though, Recomposer.current() is thread-specific, and binding to the current thread by default has been a source of issues in other Android APIs over the years. Being explicit is better here. However when you're talking about the Activity extension, Activity UI always is bound to the ActivityThread - the main thread.

[Adam Powell]

And when it comes to the future view APIs mentioned above, we can do some more contextual recomposer autodiscovery

[andylamax]

Thanks for the perfect elaborations you gave. And that makes sense a lot. In a nutshell, how is the API AbstractComposeView going to look like?

class MyView : AbstractComposeView({
   // . . . composables here
})

[Adam Powell]

Might be closer to something like

class MyView @JvmOverloads constructor(
  context: Context,
  attrs: AttributeSet? = null
) : AbstractComposeView(context, attrs) {
  @Composable
  override fun Content() {
    // ...
  }
}

[andylamax]

Wooow, I think I already like it.