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Feature Request

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Description

ri...@google.com

created issue #1

Sep 25, 2023 10:01AM

Component used: activity-compose - PredictiveBackHandler

Right now, when getting the progress events, you can tell the touchX and touchY and the progress, but you’d need to manually track the velocity to understand the velocity with which a gesture is performed.

I’d like this velocity to be able to use animateDecay, or animateTo() on Animatable, to be able to smoothly finish the animation from where it left off. To do this, I’ve added VelocityTracker, but the BackEvent doesn’t contain uptimeMillis, leading me to use System.currentTimeMillis, which could be inaccurate if an event comes in a different order.

val translationX = remember {
            Animatable(0f)
        }

        val drawerWidth = with(LocalDensity.current) {
            DrawerWidth.toPx()
        }
        translationX.updateBounds(0f, drawerWidth)
        val velocityTracker = remember {
            VelocityTracker()
        }
        PredictiveBackHandler(drawerState == DrawerState.Closed) { progress: Flow<BackEventCompat> ->
            // code for gesture back started
            try {
                progress.collect { backEvent ->
                    // code for progress
                    if (drawerState == DrawerState.Closed) {
                        translationX.snapTo(backEvent.progress * drawerWidth)
// I'd like to not need to use System time but rather the gesture event time.
                        velocityTracker.addPosition(System.currentTimeMillis(), Offset(backEvent.touchX, backEvent.touchY))
                    }
                }
                // code for completion
                val endProgress = if (translationX.value > drawerWidth * 0.5f) {
                    drawerWidth
                } else {
                    0f
                }
                translationX.animateTo(endProgress, initialVelocity = velocityTracker.calculateVelocity().x)

                if (endProgress == 0f){
                    drawerState = DrawerState.Closed
                } else {
                    drawerState = DrawerState.Open
                }
            } catch (e: CancellationException) {
                // code for cancellation
                Log.d("!!!", "predictive back gesture cancelled")
            }
        }

Comments

il...@google.com <il...@google.com> #2Sep 26, 2023 06:12PM

Assigned to sh...@google.com.

BackEventCompat is a simple wrapper around the framework BackEvent, which does not include any uptimeMillis field that we can pass through.

Over to the framework team to comment on whether System.currentItemMillis() is a reasonable back compat for this feature request and if it makes sense to make a change on the framework side separately as well.

ga...@google.com <ga...@google.com> #3Mar 5, 2025 07:15PM

Reassigned to jb...@google.com.

We have added the frameTimeMillis field to BackEvent on the framework side on Android 16. It would be great if that could be mirrored in androidx. As a back compat I would suggest to use System.nanoTime() / TimeUtils.NANOS_PER_MS.

ap...@google.com <ap...@google.com> #4Mar 18, 2025 10:21PM

Project: platform/frameworks/support
Branch: androidx-main
Author: Jeremy Woods <jbwoods@google.com>
Link: https://android-review.googlesource.com/3548541

Adding support for new APIs in BackEventCompat

Expand for full commit details

Adding support for new APIs in BackEventCompat 
 
Adding support for the new EDGE_NONE and frameTimeMillis features in the 
BackEventCompat class to ensure that it is compatible with those new 
features from the framework. 
 
RelNote: "`BackEventCompat` now provides `EDGE_NONE` as a swipe edge 
option to represent none-gesture back cases and `frameTimeMillis` which 
can be used to calculate gesture velocity." 
RelNote: "Activity is now compiled with API 36." 
Test: added tests 
Bug: 301910674 
Fixes: 400993493 
 
Change-Id: I510e8f026436f72b000eae153f627b02b1f1e2a3

Files:

M activity/activity-compose/build.gradle
M activity/activity-compose/samples/build.gradle
M activity/activity-ktx/build.gradle
M activity/activity/api/current.txt
M activity/activity/api/restricted_current.txt
M activity/activity/build.gradle
M activity/activity/src/androidTest/java/androidx/activity/BackEventCompatTest.kt
M activity/activity/src/main/java/androidx/activity/BackEventCompat.kt
M activity/integration-tests/macrobenchmark-target/build.gradle
M activity/integration-tests/testapp/build.gradle

Hash: 0d4dba6a6083a6cb65aa738adfa3def907f49829
Date: Wed Mar 05 21:19:01 2025

ap...@google.com <ap...@google.com> #5Mar 18, 2025 10:21PM

Project: platform/frameworks/support
Branch: androidx-main
Author: Jeremy Woods <jbwoods@google.com>
Link: https://android-review.googlesource.com/3549880

Remove ToT Activity deps

Expand for full commit details

Remove ToT Activity deps 
 
Changing all activity ToT dependencies that are not part of the activity 
library to stable dependencies. None of them are depending on new 
activity features. 
 
Test: ./gradlew bOS 
Bug: 301910674 
Change-Id: I196e373b5ac79b187952b2979f4c962f7f6c5088

Files:

M activity/activity-compose/build.gradle
M compose/foundation/foundation/integration-tests/foundation-demos/build.gradle
M compose/integration-tests/hero/jetsnack/jetsnack-implementation/build.gradle
M compose/integration-tests/macrobenchmark-target/build.gradle
M compose/material3/integration-tests/macrobenchmark-target/build.gradle
M compose/material3/material3/integration-tests/material3-demos/build.gradle
M compose/runtime/runtime/compose-runtime-benchmark/build.gradle
M compose/runtime/runtime/integration-tests/build.gradle
M constraintlayout/constraintlayout-compose/integration-tests/demos/build.gradle
M constraintlayout/constraintlayout-compose/integration-tests/macrobenchmark-target/build.gradle
M core/core-backported-fixes/integration-tests/testapp/build.gradle
M hilt/integration-tests/viewmodelapp/build.gradle
M hilt/integration-tests/workerapp/build.gradle
M lifecycle/lifecycle-viewmodel-compose/build.gradle
M privacysandbox/tools/integration-tests/testapp/build.gradle
M savedstate/savedstate-samples/build.gradle
M test/uiautomator/integration-tests/testapp/build.gradle
M wear/benchmark/integration-tests/macrobenchmark-target/build.gradle
M wear/compose/compose-material3/macrobenchmark-target/build.gradle
M wear/compose/integration-tests/macrobenchmark-target/build.gradle
M window/integration-tests/macrobenchmark-target/build.gradle
M xr/compose/material3/integration-tests/testapp/build.gradle

Hash: 98dd3b4174987c237e28d310641844d6196eaba2
Date: Tue Mar 18 17:46:46 2025

ap...@google.com <ap...@google.com> #6Mar 18, 2025 10:45PM

Android API Change

This bug was referenced by a recent CL that changed the Android API surface area.

The Android API Council regularly reviews API changes for consistency and sustainability, and we've just added this bug to our hotlist of pending reviews.

We'll wait until you mark this bug as 'Fixed' before starting our review, but please reach out if you'd like us to review it sooner.

Changes to activity/activity/api/current.txt

androidx.activity
androidx.activity.BackEventCompat
androidx.activity.BackEventCompat.Companion

http://go/agw/platform/frameworks/support/+/0d4dba6a6083a6cb65aa738adfa3def907f49829%5E%21
https://android-review.googlesource.com/3548541

[Gerrit:https://android-review.googlesource.com/3548541]
[API-Approvers:ilake@google.com]
[Branch:androidx-main]

[LIBRARY_API_REVIEW_TAG:activity/activity/api/current.txt]

jb...@google.com <jb...@google.com> #7Mar 19, 2025 03:24AM

Marked as fixed.

This has been added internally and will be available in the Activity 1.11.0-alpha02 release.

gr...@google.com <gr...@google.com> #8Mar 27, 2025 04:04PM

Verified by gr...@google.com.

Good news! Wear Compose has been updated to ab/13249763 in

https://critique.corp.google.com/cl/741116702 and this bug has been affected.

IssueTracker

PredictiveBackHandler: Expose uptimeMillis on BackEvent

Status Update

Description

Comments

il...@google.com <il...@google.com> #2Sep 26, 2023 06:12PM

ga...@google.com <ga...@google.com> #3Mar 5, 2025 07:15PM

ap...@google.com <ap...@google.com> #4Mar 18, 2025 10:21PM

ap...@google.com <ap...@google.com> #5Mar 18, 2025 10:21PM

ap...@google.com <ap...@google.com> #6Mar 18, 2025 10:45PM

Android API Change

jb...@google.com <jb...@google.com> #7Mar 19, 2025 03:24AM

gr...@google.com <gr...@google.com> #8Mar 27, 2025 04:04PM

Issue 301910674

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Issue summary

Comments

il...@google.com <il...@google.com> #2Sep 26, 2023 06:12PM

ga...@google.com <ga...@google.com> #3Mar 5, 2025 07:15PM

ap...@google.com <ap...@google.com> #4Mar 18, 2025 10:21PM

ap...@google.com <ap...@google.com> #5Mar 18, 2025 10:21PM

ap...@google.com <ap...@google.com> #6Mar 18, 2025 10:45PM

Android API Change

jb...@google.com <jb...@google.com> #7Mar 19, 2025 03:24AM

gr...@google.com <gr...@google.com> #8Mar 27, 2025 04:04PM

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