Support linking compositions created on ViewGroups to parent CompositionReferences [156527485]

Fixed

Bug

Status Update

No update yet.

Description

za...@gmail.com

created issue #1

May 13, 2020 10:17PM

I’ve got a view/composable structure like this:

@Composable Foo() {
    Providers(MyAmbient provides foo) {
        // <-- [REF] Capture the composition here…
        AndroidView(R.layout.bar) { view ->
            view.setContent {
                // <-- [DEREF] …and resume it here.
                Baz(MyAmbient.current)
            }
        }
    }
}

And I want that innermost composable to be able to access ambients from the outer one.

The way to do this is first to call compositionReference() on the line commented [REF], and then use it to create the composition on the line above [DEREF]. compositionReference() is a public function, and works as expected. Compose APIs such compositionFor() and subcomposeInto() accept a CompositionReference parameter, but are lower-level than is convenient to use from regular view code (they require dealing with ComponentNodes). There's currently no way to pass the CompositionReference into the child composition.

The simplest way to support this would be for ViewGroup.setContent to take an optional CompositionReference parameter and plumb it through to the deepest compositionFor call. I've proven this works using reflection to access private APIs here.

This was initially discussed in this Slack thread.

Comments

le...@google.com <le...@google.com> #2May 14, 2020 12:23AM

Assigned to po...@google.com.

Adding Andrey and Mihai to this. What do you guys think about this? We should consider this a pretty valid use case IMO, and right now the API to do it doesn't really exist.

an...@google.com <an...@google.com> #3May 14, 2020 10:09AM

I agree the proposed fix is a way to go. we should also migrate to start using it in our Popup and Dialog

po...@google.com <po...@google.com> #4May 14, 2020 12:11PM

Yes, this is surely needed. b/154369470 is tracking the symptom of this in Dialog.

ap...@google.com <ap...@google.com> #5Jun 25, 2020 07:27PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit b300d2cd6ccab823bf4dea7fea62d52f9e6ed53c
Author: Mihai Popa <popam@google.com>
Date: Tue Jun 23 16:25:50 2020

Link ViewGroup compositions to existing ones

The CL adds API to link the compositions started via
ViewGroup#setContent to the enclosing composition. This enables proper
invalidations and ambients propagation across the subcomposition border.
Based on this API, Dialogs, Popups and DropdownMenus are now able to inherit
ambients (e.g. MaterialTheme) from the wrapping composition.

Relnote: Popups, Dialogs and Menus are now inheriting the contextual MaterialTheme
Bug: 156527485
Bug: 144091550
Bug: 158804197
Bug: 158794412
Test: WrapperTest, PopupTest, DialogTest
Change-Id: Ia3665905218b4d12d7a9bd121a69a51569d82694

M ui/ui-core/api/0.1.0-dev15.txt
M ui/ui-core/api/current.txt
M ui/ui-core/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-core/api/public_plus_experimental_current.txt
M ui/ui-core/api/restricted_0.1.0-dev15.txt
M ui/ui-core/api/restricted_current.txt
M ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/core/PopupTest.kt
M ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/core/test/WrapperTest.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/Popup.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/Wrapper.kt
M ui/ui-desktop/src/jvmMain/kotlin/androidx/ui/desktop/Wrapper.kt
M ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/DialogUiTest.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt
M ui/ui-material/src/main/java/androidx/ui/material/AlertDialog.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/ActivityWithActionBar.kt

https://android-review.googlesource.com/1347523

po...@google.com <po...@google.com> Jun 26, 2020 12:28AM

Marked as fixed.

Issue 156527485