Bug P2
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kl...@google.com
Project: platform/frameworks/support
Branch: androidx-main
Author: Louis Pullen-Freilich <
Link:
Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling
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Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling
These APIs allow overscroll to have events dispatched to it by one component, and rendered in a separate component.
Fixes: b/266550551
Fixes: b/204650733
Fixes: b/255554340
Fixes: b/229537244
Test: OverscrollTest
Relnote: "Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling APIs - these APIs create a wrapped instance of the provided overscroll effect that doesn't draw / handle events respectively, which allows for rendering overscroll in a separate component from the component that is dispatching events. For example, disabling drawing the overscroll inside a lazy list, and then drawing the overscroll separately on top / elsewhere."
Change-Id: Idbb3d91546b49c1987a041f959bce4b2b09a9f61
Files:
- M
compose/foundation/foundation/api/current.txt - M
compose/foundation/foundation/api/restricted_current.txt - M
compose/foundation/foundation/integration-tests/foundation-demos/src/main/java/androidx/compose/foundation/demos/OverscrollDemo.kt - M
compose/foundation/foundation/samples/src/main/java/androidx/compose/foundation/samples/OverscrollSample.kt - M
compose/foundation/foundation/src/androidInstrumentedTest/kotlin/androidx/compose/foundation/OverscrollTest.kt - M
compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/Overscroll.kt
Hash: f64e25b7a473c757d080521e7dd97b3f6670f60d
Date: Fri Nov 01 18:43:56 2024
ap...@google.com
The following release(s) address this bug.It is possible this bug has only been partially addressed:
androidx.compose.foundation:foundation:1.8.0-alpha06androidx.compose.foundation:foundation-android:1.8.0-alpha06androidx.compose.foundation:foundation-jvmstubs:1.8.0-alpha06androidx.compose.foundation:foundation-linuxx64stubs:1.8.0-alpha06
kl...@google.com
This is no longer blocking me, assigning to Levi to figure out if it's something we want to support.
Description
If
ScrollableState.animateScrollByis called and then before it completes it is called again in another coroutine, the first animation will be cancelled before starting the second one. However, unlike calls toAnimatable.animateTo, the velocity of the previous animation will not be preserved.Possible solutions
This isn't a trivial fix because
ScrollableStateitself does not keep any animation or velocity state –animateScrollByis an extension function. It also does not provide any signal about whether it's being scrolled by an animation or the user, so if we track the velocity externally then we could end up in a weird state if the user interrupts an animation.Option 1: Move
animateScrollByintoScrollableStateThis would allow
ScrollableStateto keep track of animated scroll velocity internally. It should also allow it to be reset to zero when the animation is interrupted by a user scroll. However,ScrollableStateis a public interface so to avoid breaking binary compatibility we would need to wait for Kotlin 1.6.20 and then give it a default implementation. The default implementation could simply be the current implementation.Option 2: Expose scroll velocity from
ScrollableStateI'm not sure how feasible this is – tracking velocity requires tracking timestamps, which
ScrollableStatedoes not currently do and would probably make the API super gross.