Hmm. After a couple of weeks of life coming in the way I'm back to Composing and trying to embed an AndroidView into my dev07 based compose app. I have been using this example code some kind composer pointed me at: https://cs.android.com/androidx/platform/frameworks/support/+/androidx-master-dev:ui/ui-android-view/src/main/java/androidx/ui/androidview/ComposedView.kt?q=AndroidView&ss=androidx%2Fplatform%2Fframeworks%2Fsupport but looking at the code I must be missing some key undertanding. I see where it inflates the view and adds the view to the AndroidViewHolder (a ViewGroup). But I don't see the code that adds that view group into the hierarchy of views in the content of the activity?

That

ViewGroup

is emitted during composition and we are handling it being composed here: https://osscs.corp.google.com/androidx/platform/frameworks/support/+/androidx-master-dev:ui/ui-framework/src/main/java/androidx/ui/node/UiComposer.kt;l=134?q=uicomposer.kt

@Mihai Popa Oh, I see (I think?) so when inside of an @ Compose function, there is some bit of extra compiler instrumentation goo that allows the runtime to see any creation of View objects (they magically end up in pendingInserts somehow? - in the example code I was looking at I only see creation of a ViewGroup, not adding it to any other structure). And if a View object is created (but not even added underneath a View already in the Window hierarchy) the compose runtime takes care of adding it later? Thank you for helping with this, because I tried a variant of this example code (though I needed to update it a bit to make it work with dev07) and was puzzled. If I add breakpoints, I see my view getting created, but it never gets a surface (unsurprisingly because I don't see it getting added to the view hierarchy) https://github.com/geeksville/Meshtastic-Android/blob/map/app/src/main/java/androidx/ui/fakeandroidview/ComposedView.kt#L45

It's not really any creation of

View

, but the Compose runtime will handle the creation of `View`s when you emit them (i.e. use the DSL-style syntax as if you executed a

@Composable

but with a

View

instead). This is how

AndroidViewHolder

is emitted, not just created

oh! I didn't realize you could use DSL syntax for creating views!

yep, exactly

hmm. If I try to do this I get an error on the call to AndroidViewHolder() "No value passed for parameter 'context'). Is it possible that example code depends on a compiler version not yet released?

@Composable
// TODO(popam): support modifiers here
fun AndroidView(@LayoutRes resId: Int, postInflationCallback: (View) -> Unit = { _ -> }) {
    AndroidViewHolder()
    //r.postInflationCallback = postInflationCallback
    //r.resId = resId
}


private class AndroidViewHolder(context: Context) : ViewGroup(context)

yeah, that code is working for me

thank you for your help. sorry I missed that line in the first place though. keep rocking it. Super awesome out engaged all you composegeeks are

Yeah, currently we are not passing along touch events for Views

ok thanks! alas! keep rocking it