onDragStart called after onDrag [187320697]

Fixed

Bug

Status Update

No update yet.

Description

ha...@google.com

created issue #1

May 5, 2021 07:01PM

Steps to reproduce: Run the following code:

Box(
    modifier = Modifier.background(Color.Cyan).pointerInput(Unit) {
        detectDragGestures(
            onDragStart = {
                dragStarted = true
                Log.e("debugTag", "onDragStart")
            },
            onDragEnd = {
                dragStarted = false
                Log.e("debugTag", "onDragEnd")
            },
            onDragCancel = {
                dragStarted = false
                Log.e("debugTag", "onDragCancel")
            },
        ) { change, dragAmount ->
            change.consumeAllChanges()
            if (!dragStarted) {
                Log.e("debugTag", "onDrag called before onStart")
            } else {
                Log.e("debugTag", "onDrag")
            }
        }
    }
)

Drag anywhere in the Box.
Check the log, we can find that onDrag is always called once before onDragStart get called.

Example:

2021-05-05 11:59:43.653 19756-19756/androidx.compose.integration.demos E/debugTag: onDrag called before onStart
2021-05-05 11:59:43.653 19756-19756/androidx.compose.integration.demos E/debugTag: onDragStart
2021-05-05 11:59:43.669 19756-19756/androidx.compose.integration.demos E/debugTag: onDrag
2021-05-05 11:59:43.686 19756-19756/androidx.compose.integration.demos E/debugTag: onDrag
2021-05-05 11:59:43.703 19756-19756/androidx.compose.integration.demos E/debugTag: onDrag
2021-05-05 11:59:43.719 19756-19756/androidx.compose.integration.demos E/debugTag: onDrag
2021-05-05 11:59:43.736 19756-19756/androidx.compose.integration.demos E/debugTag: onDrag
2021-05-05 11:59:43.748 19756-19756/androidx.compose.integration.demos E/debugTag: onDrag
2021-05-05 11:59:43.749 19756-19756/androidx.compose.integration.demos E/debugTag: onDragEnd

Comments

an...@google.com <an...@google.com> May 20, 2021 11:26AM

Assigned to ma...@google.com.

ap...@google.com <ap...@google.com> #2May 20, 2021 12:18PM

Marked as fixed.

Thanks! This looks like a bug, thank you for reporting!

ch...@gmail.com <ch...@gmail.com> #3Jun 11, 2021 02:37PM

I would also recommend setting the value to 10%. When you do that, the behavior is wild.

Dragging up to 10% or between 50% and 90% will cause it to snap back to the start anchor.
Dragging between 10% and 50% or past 90% will cause it to snap to the end anchor.

Message last modified on Jun 12, 2021 03:06AM

ma...@google.com <ma...@google.com> #4Jun 11, 2021 02:46PM

Project: platform/frameworks/support
Branch: androidx-main
Author: Jossi Wolf <jossiwolf@google.com>
Link: https://android-review.googlesource.com/3278651

Update AnchoredDraggable target calculation logic

Expand for full commit details

Update AnchoredDraggable target calculation logic

We were previously relying on currentValue and the next closest anchor in the drag direction, but the simpler and more reliable way is to look at the left and right anchors as the window.

Relnote: Fixed a bug where positional thresholds passed to AnchoredDraggableDefaults.flingBehavior were not considered correctly in some scenarios.
Test: anchoredDraggable_fling_offsetPastHalfwayBetweenAnchors_beforePosThreshold_doesntAdvance
Bug: 367660226
Bug: 366003852
Change-Id: Ifdf0dfcf3d7ff8288affee56e7092bbed473d6ab

Files:

M compose/foundation/foundation/src/androidInstrumentedTest/kotlin/androidx/compose/foundation/anchoredDraggable/AnchoredDraggableStateTest.kt
D compose/foundation/foundation/src/androidInstrumentedTest/kotlin/androidx/compose/foundation/anchoredDraggable/AnchoredDraggableTestState.kt
M compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/gestures/AnchoredDraggable.kt

Hash: eff53304942e9fd4fa5382e0cf487a734c5b8d28
Date: Thu Sep 19 16:24:55 2024

ch...@gmail.com <ch...@gmail.com> #5Jun 12, 2021 02:40AM

Any estimate on when will this release?

ma...@google.com <ma...@google.com> #6Jun 14, 2021 10:49AM

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

androidx.compose.foundation:foundation:1.8.0-alpha04
androidx.compose.foundation:foundation-android:1.8.0-alpha04
androidx.compose.foundation:foundation-jvmstubs:1.8.0-alpha04

Issue 187320697