Expose shortSnapVelocityThreshold as a parameter in PagerDefaults.flingBehavior [275579012]

Fixed

Bug

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Description

ma...@perrystreet.com

created issue #1

Mar 29, 2023 10:02AM

Jetpack Compose version: 1.4.0

Jetpack Compose component(s) used: Pager

It is now a lot harder to customize the required fling to snap to a page, because shortSnapVelocityThreshold parameter is not exposed to the fling creation function and everything is private inside the Pager file.

Before I could simply do something like this:

private class FlingBehaviourMultiplier(
    private val multiplier: Float,
    private val baseFlingBehavior: FlingBehavior
) : FlingBehavior {
    override suspend fun ScrollScope.performFling(initialVelocity: Float): Float {
        return with(baseFlingBehavior) {
            performFling(initialVelocity * multiplier)
        }
    }
}

but now this is also not possible because SnapFlingBehavior is a concrete class instead of an interface and I'd need to provide all the constructor params and I cannot take advantage of the SnapLayoutInfoProvider class since it's also private.

Comments

jo...@google.com <jo...@google.com> Mar 29, 2023 10:10AM

Reassigned to le...@google.com.

ap...@google.com <ap...@google.com> #2Apr 13, 2023 12:40PM

Marked as fixed.

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

commit 452d89091e65de10088498a57e2e1ff26127b00e
Author: Levi Albuquerque <levima@google.com>
Date: Tue Apr 11 14:40:08 2023

Allow customization of shortSnapVelocityThreshold in Pager.

shortSnapVelocityThreshold was the only parameter in SnapFlingBehavior that wasn't customizable in Pager. We can enable its customization so developers can change it without the need to instantiate their own SnapFlingBehavior (which is currently not possible because the PagerLayoutInfoProvider is private).

Relnote: Introduce shortSnapVelocityThreshold in Pager's SnapFlingBehavior.

Test: Previous tests should pass.
Fixes: 275579012
Change-Id: I7379e457b8b7321aba6605a81cccd2245122a80e

M compose/foundation/foundation/api/public_plus_experimental_current.txt
M compose/foundation/foundation/src/androidAndroidTest/kotlin/androidx/compose/foundation/pager/BasePagerTest.kt
M compose/foundation/foundation/src/androidAndroidTest/kotlin/androidx/compose/foundation/pager/PagerScrollingTest.kt
M compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/pager/Pager.kt

https://android-review.googlesource.com/2531123

na...@google.com <na...@google.com> #3May 10, 2023 07:08PM

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

androidx.compose.foundation:foundation:1.5.0-alpha04

Issue 275579012

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jo...@google.com <jo...@google.com> Mar 29, 2023 10:10AM

ap...@google.com <ap...@google.com> #2Apr 13, 2023 12:40PM

na...@google.com <na...@google.com> #3May 10, 2023 07:08PM

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