Lifecycle as Flow [176311030]

Fixed

Feature Request

Status Update

No update yet.

Description

p1...@gmail.com

created issue #1

Dec 25, 2020 09:24PM

Please provide extension for lifecycle to observe Lifecycle.Event as Flow.

Also present you my workaround

fun Lifecycle.asFlow() = callbackFlow<Lifecycle.Event> {

val observer = ALifecycleObserver(this@asFlow) { offer(it) }

awaitClose { removeObserver(observer) }

}

class ALifecycleObserver(
lifecycle: Lifecycle,
private val action: (Lifecycle.Event) -> Unit
): LifecycleObserver {

init { lifecycle.addObserver(this) }

@OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
fun onCreate(event: Lifecycle.Event) = action.invoke(event)

@OnLifecycleEvent(Lifecycle.Event.ON_START)
fun onStart(event: Lifecycle.Event) = action.invoke(event)

@OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
fun onResume(event: Lifecycle.Event) = action.invoke(event)

@OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
fun onPause(event: Lifecycle.Event) = action.invoke(event)

@OnLifecycleEvent(Lifecycle.Event.ON_STOP)
fun onStop(event: Lifecycle.Event) = action.invoke(event)

@OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
fun onDestroy(event: Lifecycle.Event) = action.invoke(event)
}

Comments

p1...@gmail.com <p1...@gmail.com> #2Dec 25, 2020 11:24PM

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

commit c60f33e229e31ab328ef6b59dab63b264954831c
Author: Alexandre Elias <aelias@google.com>
Date: Fri Jul 10 16:23:09 2020

Semantics no-op cleanups

Partly in response to lmr's broad code review, I did a pass of
superficial API/implementation cleanup. The main changes are:

- I changed each Boolean SemanticsProperty where false is equivalent to
not being present to take "Unit" instead. This is conceptually
clearer: it avoids questions like "can I cancel out a semantics from a
merged child by setting it to false?" Because "property = Unit" looks
weird, I also changed the style of these to "property()".

- I moved the Semantics id generator closer to where it's used, in
SemanticsModifierCore. I made it internal and an AtomicInt.
(Note that integer ids are heavily used in the Android
AccessibilityNodeInfo APIs so I can't simply remove them entirely.)

- I deleted dead code. Some examples include SemanticsHintOverrides,
a public API not connected to anything, and SemanticsPropertyKey
merge() open method which is never called. (In both cases I have
a different plan in mind for accessibility.)

Fixes: 145951226
Fixes: 145955412
Test: existing tests
Relnote: "Single-value semantics properties now use a calling style.
For example, 'semantics { hidden = true }' is now written as:
'semantics { hidden() }'."

Change-Id: Ic1afd12ea22c926babc9662f1804d80b33aa0cfc

M ui/integration-tests/benchmark/src/androidTest/java/androidx/ui/benchmark/test/LayoutNodeModifierBenchmark.kt
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/graphics/vector/VectorTest.kt
M ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/semantics/SemanticsTests.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidActuals.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeView.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeViewAccessibilityDelegateCompat.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidPopup.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/Expect.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsConfiguration.kt
D ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsHintOverrides.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsModifier.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsNode.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsOwner.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsWrapper.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/semantics/SemanticsProperties.kt
M ui/ui-foundation/api/0.1.0-dev15.txt
M ui/ui-foundation/api/current.txt
M ui/ui-foundation/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-foundation/api/public_plus_experimental_current.txt
M ui/ui-foundation/api/restricted_0.1.0-dev15.txt
M ui/ui-foundation/api/restricted_current.txt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Selectable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/semantics/FoundationSemanticsProperties.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ButtonTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/CardTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/CheckboxScreenshotTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/RadioButtonScreenshotTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ScaffoldTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/SnackbarTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/SurfaceTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ripple/RippleIndicationTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/textfield/TextFieldScreenshotTest.kt
M ui/ui-material/src/main/java/androidx/ui/material/AppBar.kt
M ui/ui-material/src/main/java/androidx/ui/material/TextFieldImpl.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/AssertsTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/CallSemanticsActionTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/ErrorMessagesTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/FindersTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/PrintToStringTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/ScrollToTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/TextActionsTest.kt
M ui/ui-test/src/main/java/androidx/ui/test/Actions.kt
M ui/ui-test/src/main/java/androidx/ui/test/Filters.kt
M ui/ui-text/api/0.1.0-dev15.txt
M ui/ui-text/api/current.txt
M ui/ui-text/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-text/api/public_plus_experimental_current.txt
M ui/ui-text/api/restricted_0.1.0-dev15.txt
M ui/ui-text/api/restricted_current.txt
M ui/ui-text/src/commonMain/kotlin/androidx/ui/text/CoreTextField.kt
M ui/ui-text/src/commonMain/kotlin/androidx/ui/text/TextSemanticsProperties.kt

https://android-review.googlesource.com/1360099

se...@google.com <se...@google.com> #3Jan 6, 2021 01:22PM

We previously discussed in the tea whether this extension should be provided out of box.

Currently, it was decided not to provide it, because it seems niche and not really needed at one hand, and very easy to implement for developers who want it at the other.

Implementation-wise, I'd note that ALifecycleObserver can be replaced with LifecycleEventObserver, which makes your snippet even smaller.

Gonna mark it as Feature Request and leave it open to see if there is an appetite for this API as official extension.

p1...@gmail.com <p1...@gmail.com> #4Jan 6, 2021 01:54PM

Okay, thanks. Final version :

fun Lifecycle.asFlow() = callbackFlow<Lifecycle.Event> {

val observer = LifecycleEventObserver { _, event ->
if (!isClosedForSend) offer(event)
}.also { this@asFlow.addObserver(it) }

awaitClose { removeObserver(observer) }
}.flowOn(Dispatchers.Main)

https://hatebin.com/ijgshyydfq

il...@google.com <il...@google.com> Nov 18, 2021 10:12PM

Status: New

ca...@google.com <ca...@google.com> #5Jan 28, 2022 06:40PM

This is something I also added as a workaround. It seems like a natural API to include in Jetpack.

il...@google.com <il...@google.com> Sep 12, 2022 11:51PM

Assigned to sa...@google.com.

ey...@gmail.com <ey...@gmail.com> #6Jan 17, 2023 10:59PM

I was very surprised that this wasn't included in Jetpack.

it...@gmail.com <it...@gmail.com> #7Jan 20, 2023 01:16AM

I ended up incorporating this workaround, too. Makes a ton of sense to make this observable.

sa...@google.com <sa...@google.com> Feb 8, 2023 10:41PM

Accepted by sa...@google.com.

ap...@google.com <ap...@google.com> #8Mar 3, 2023 10:24PM

Project: platform/frameworks/support
Branch: androidx-main

commit 2f35da31af699a8b91439c53d9eb43840da6551b
Author: sanura <sanura@google.com>
Date: Thu Feb 09 01:47:28 2023

Expose Lifecycle as a Flow<Lifecycle.Event>

Adding an extension method to Lifecycle that
will allow observing Lifecycle.Event as a Flow.

RelNote: "`Lifecycle.Event`s are now able to be
observed as a `Flow` with `Lifecycle.asFlow().`"
Bug: 176311030
Test: LifecycleAsFlowTest

Change-Id: If2c0f10760caca7109d43c235ea76437ef2af5dc

M lifecycle/lifecycle-common/api/current.txt
M lifecycle/lifecycle-common/api/public_plus_experimental_current.txt
M lifecycle/lifecycle-common/api/restricted_current.txt
M lifecycle/lifecycle-common/build.gradle
M lifecycle/lifecycle-common/src/main/java/androidx/lifecycle/Lifecycle.kt
A lifecycle/lifecycle-runtime-testing/src/test/java/androidx/lifecycle/testing/LifecycleEventFlowTest.kt

https://android-review.googlesource.com/2427280

it...@gmail.com <it...@gmail.com> #9Mar 4, 2023 12:18AM

#8 you might want to remove that email from your comment, as emails are typically obfuscated in these threads

sa...@google.com <sa...@google.com> Mar 6, 2023 07:43PM

Marked as fixed.

na...@google.com <na...@google.com> #10Jul 26, 2023 05:21PM

The following release(s) address this bug.It is possible this bug has only been partially addressed:

androidx.lifecycle:lifecycle-common:2.7.0-alpha01
androidx.lifecycle:lifecycle-runtime-testing:2.7.0-alpha01