Added debouncing to prevent from frequent triggering by jatinkumar2409 · Pull Request #20879 · ankidroid/Anki-Android

jatinkumar2409 · 2026-04-28T07:40:02Z

Purpose / Description

The shake gesture was triggering multiple times on frequent shakes

Fixes

Fixes Shake gesture shouldn't trigger repeatedly #20810

Approach

Added debouncing so that there should be atleast 2500ms between two shake gestures to prevent frequent triggering

How Has This Been Tested?

ankidroid_shake_fix.mp4

You can set the shake gesture to any of the action specifically "set due date" and try to shake frequently on old screen and you can test with adding or editing notes in new study screen

Learning (optional, can help others)

Describe the research stage

Links to blog posts, patterns, libraries or addons used to solve this problem

Checklist

Please, go through these checks before submitting the PR.

You have a descriptive commit message with a short title (first line, max 50 chars).
You have commented your code, particularly in hard-to-understand areas
You have performed a self-review of your own code
UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
UI Changes: You have tested your change using the Google Accessibility Scanner

david-allison

Thanks!!

Could you clean the diff (files changed tab) so only relevant changes are visible

Feel free to squash + force push, the unnecessary changes make it hard to understand the intent of the change

From the "files changed", this does not appear to impact the new study screen (ReviewerFragment)

jatinkumar2409 · 2026-04-28T10:38:12Z

Thank you @david-allison for guiding me , I am working on this . Will update it soon

ZornHadNoChoice · 2026-04-28T11:27:58Z

3000ms feels too much, doesn't it? Is 500ms or even 1000ms not enough to prevent the bug?

jatinkumar2409 · 2026-04-28T11:34:48Z

@ZornHadNoChoice Yeah in new devices 1000ms is enough but i tested in my 2gb realme c30s and it was easily crossing 1000ms that too on frequent shakes. So , for keeping older and low ram devices in mind i changed it to 2500ms and its working fine now

BrayanDSO

Subclassing ShakeDetector would be cleaner IMO

david-allison

Thanks!!

Architecturally, this would be better handled inside a custom ShakeDetector. See how we construct it here:

Anki-Android/AnkiDroid/src/main/java/com/ichi2/anki/ui/windows/reviewer/ReviewerFragment.kt

Lines 360 to 361 in f1a3305

    
           shakeDetector = ShakeDetector(this) 
        
           shakeDetector?.start(sensorManager, SensorManager.SENSOR_DELAY_UI)

This also opens us up for future refactorings: removing sensorManager from ReviewerFragment and moving it into the custom class.

I'll need to test the debounce threshold on a physical phone. Regardless of the outcome, the constant should be extracted, and the reason that you selected the value should be documented.

Use a Duration for the time: val cooldown = 2500.milliseconds or val cooldown = 2.5.seconds

BrayanDSO · 2026-04-28T14:30:16Z

probably 1500ms or 2000ms is good enough

jatinkumar2409 · 2026-04-28T14:36:57Z

@BrayanDSO yeah 1500ms or 2000ms can be good but 2500 is for old and laggy phones

jatinkumar2409 · 2026-04-28T14:53:18Z

@david-allison i am creating the wrapper in com.ichi2.anki.utils directory

jatinkumar2409 · 2026-04-29T18:08:50Z

@david-allison I have created the custom class for sensorManager. Requested for your review

david-allison

Looks great! Implementers choice on these nitpicks.

Only request is knowing where the 2500 came from

david-allison · 2026-04-30T03:40:15Z

+    private val sensorManager: SensorManager?,
+    private val sensorDelay: Int,
+    private val listener: ShakeDetector.Listener,
+//    The minimum time between two shakes in milliseconds . 2500 is used as default value


Why did you select this value? Due to your testing on what device?

I chose this value because the setduedate dialog of AbstractFlashCardViewer (legacy screen) was appearing multiple times during frequent shaking in my realme c30s . It is the older 2gb ram phone , so i thought this problem can also arise in more older phones. That's why to be safe , i chose higher threshold

the time logic should work the same independently of how slow the phone is

This should be a comment in the code.

As Brayan said, timing should also be phone-independent, select a value which works for you here, don't make assumptions we'll need to be safe for legacy hardware.

jatinkumar2409 · 2026-04-30T10:32:10Z

@david-allison
I chose this 2500 as threshold because the setduedate dialog of AbstractFlashCardViewer (legacy screen) was appearing multiple times during frequent shaking in my realme c30s . It is the older 2gb ram phone , so i thought this problem can also arise in more older phones. That's why to be safe , i chose higher threshold

jatinkumar2409 · 2026-04-30T11:08:32Z

@david-allison fixed the requested changes . Require your review

david-allison · 2026-04-30T15:06:49Z

+ * in rapid succession during a single physical shake event.
+ */
+class AnkiShakeDetector(
+//  The sensor manager to use for the shake detection


Suggested change

// The sensor manager to use for the shake detection

david-allison · 2026-04-30T15:08:32Z

+    private val sensorManager: SensorManager?,
+    private val sensorDelay: Int,
+    private val listener: ShakeDetector.Listener,
+//    The minimum time between two shakes in milliseconds . 2500 is used as default value


This should be a comment in the code.

As Brayan said, timing should also be phone-independent, select a value which works for you here, don't make assumptions we'll need to be safe for legacy hardware.

jatinkumar2409 · 2026-04-30T16:23:22Z

@david-allison your requested changes have already fixed . You reviewed the older code as your comments have outdated . Can you please recheck it . As i moved the AnkiShakeDetector from utils directory to android

david-allison · 2026-04-30T17:27:06Z

Thanks! #20879 (comment) is still pending

jatinkumar2409 · 2026-05-05T17:21:35Z

@BrayanDSO I updated the code . Needs your review

BrayanDSO

LGTM. Thanks

BrayanDSO · 2026-05-05T18:13:40Z

+import kotlin.time.Duration.Companion.milliseconds
+
+/*
+ *  Wrapper for a [ShakeDetector] to provide a cooldown mechanism.


Suggested change

* Wrapper for a [ShakeDetector] to provide a cooldown mechanism.

* Wrapper for a [ShakeDetector] to provide a cooldown mechanism.

jatinkumar2409 · 2026-05-06T09:16:47Z

@david-allison @BrayanDSO Thank you for mentoring me in this issue . As this was my first open source contribution . Can i get the short feedback so that i can improve for future contributions.
Thank you

BrayanDSO

You mixed your commit with another one. Please rebase your branch with only our changes

jatinkumar2409 · 2026-05-06T10:27:09Z

@BrayanDSO I fixed that

BrayanDSO · 2026-05-06T14:41:48Z

address David's comment about the copyright header

jatinkumar2409 · 2026-05-06T16:18:26Z

@BrayanDSO It was just the small formatting . I already fixed that

BrayanDSO · 2026-05-06T16:47:02Z

so push the changes. It looks the same here.

jatinkumar2409 · 2026-05-06T16:52:56Z

@BrayanDSO Fixed that

BrayanDSO

other cleanups can be made later. LGTM

jatinkumar2409 · 2026-05-06T18:18:49Z

@BrayanDSO Can this be merged now

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jatinkumar2409 force-pushed the main branch from 4df5983 to 95b1b8d Compare April 28, 2026 11:20

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jatinkumar2409 force-pushed the main branch from f1bca4e to de9793c Compare April 28, 2026 18:24

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david-allison reviewed Apr 30, 2026

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Comment thread AnkiDroid/src/main/java/com/ichi2/anki/utils/AnkiShakeDetector.kt Outdated

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Comment thread AnkiDroid/src/main/java/com/ichi2/anki/utils/AnkiShakeDetector.kt Outdated

jatinkumar2409 force-pushed the main branch from de9793c to 9a329fd Compare April 30, 2026 10:46

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jatinkumar2409 force-pushed the main branch from 9a329fd to e53c94e Compare April 30, 2026 16:28

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jatinkumar2409 force-pushed the main branch 2 times, most recently from 1dad002 to be22fef Compare May 6, 2026 09:49

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jatinkumar2409 force-pushed the main branch from be22fef to 5c22b48 Compare May 6, 2026 10:14

jatinkumar2409 requested a review from BrayanDSO May 6, 2026 10:44

added debouncing to prevent frequent triggering

68592bc

jatinkumar2409 force-pushed the main branch from 5c22b48 to 68592bc Compare May 6, 2026 17:03

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BrayanDSO added Pending Merge Things with approval that are waiting future merge (e.g. targets a future release, CI wait, etc) and removed Needs Author Reply Waiting for a reply from the original author labels May 7, 2026

Merged via the queue into ankidroid:main with commit 23b04d9 May 7, 2026
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github-actions Bot added this to the 2.25 release milestone May 7, 2026

	shakeDetector = ShakeDetector(this)
	shakeDetector?.start(sensorManager, SensorManager.SENSOR_DELAY_UI)

	* Wrapper for a [ShakeDetector] to provide a cooldown mechanism.
	* Wrapper for a [ShakeDetector] to provide a cooldown mechanism.

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Purpose / Description

Fixes

Approach

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jatinkumar2409 commented Apr 28, 2026 •

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