(Android/FlatList) Fix onMomentumScrollEnd being called multiple times

[huangkaiyuan]

Description

Version

0.64.1

Output of react-native info

Steps to reproduce

Snack, code example, screenshot, or link to a repository

No response

[fanyangxi]

Observing the same symptom. FYI, the onMomentumScrollBegin was triggered only once, but the onMomentumScrollEnd was trigged around 3~5 times.

[Arjan-Zuidema]

Same bug occurs on the ScrollView component

[meowcorp]

+1

[anton-patrushev]

Was able to reproduce it on the 0.66.4 version. Android only. Hermes is enabled (maybe it would be useful). I have faced with that issue on 0.64.2 first time. But it's still reproducible.

[rubydeve]

+1

[rubydeve]

This is how it worked for me

const [canmomentum, setCanMomentum] = useState(false);
<ScrollView
      onScroll={( event ) => {
           setCanMomentum(true)
     }}
     onMomentumScrollEnd={() => {
           if (canmomentum) console.log('onMomentumScrollEnd')
           setCanMomentum(false)
     }}
>
     <Content/>
</ScrollView>

[ewnavilae]

This is how it worked for me

const [canmomentum, setCanMomentum] = useState(false);
<ScrollView
      onScroll={( event ) => {
           setCanMomentum(true)
     }}
     onMomentumScrollEnd={() => {
           if (canmomentum) console.log('onMomentumScrollEnd')
           setCanMomentum(false)
     }}
>
     <Content/>
</ScrollView>

Thanks for this suggestion, I did something similar but with a ref instead to avoid unnecessary state updates and renders.

[achiyazigi]

This is how it worked for me

const [canmomentum, setCanMomentum] = useState(false);
<ScrollView
      onScroll={( event ) => {
           setCanMomentum(true)
     }}
     onMomentumScrollEnd={() => {
           if (canmomentum) console.log('onMomentumScrollEnd')
           setCanMomentum(false)
     }}
>
     <Content/>
</ScrollView>

Thanks for this suggestion, I did something similar but with a ref instead to avoid unnecessary state updates and renders.

I didn't find how to reference the scrolling state from ref. would you agree to share your solution?

[asr1191]

This is how it worked for me

const [canmomentum, setCanMomentum] = useState(false);
<ScrollView
      onScroll={( event ) => {
           setCanMomentum(true)
     }}
     onMomentumScrollEnd={() => {
           if (canmomentum) console.log('onMomentumScrollEnd')
           setCanMomentum(false)
     }}
>
     <Content/>
</ScrollView>

Thanks for this suggestion, I did something similar but with a ref instead to avoid unnecessary state updates and renders.

I didn't find how to reference the scrolling state from ref. would you agree to share your solution?

Second this, please share thy precious knowledge of the hooks. Saveth me from mine own perils! @ewnavilae I beg of you.

[josecarlosrx]

Solution using useRef:

const canMomentum = React.useRef(false);

const onMomentumScrollBegin = () => {
  canMomentum.current = true;
};

const onMomentumScrollEnd = () => {
  if (canMomentum.current) {
    // console.log('onMomentumScrollEnd');
  }

  canMomentum.current = false;
};

return (
  <ScrollView
    onMomentumScrollBegin={onMomentumScrollBegin}
    onMomentumScrollEnd={onMomentumScrollEnd}
  ></ScrollView>
);

[MarceloNascc]

I'm having the same issue in version 0.68.2

[RobbertMerapar]

Still an issue in version 0.69.6

[MichHighlander]

Still an issue in version 0.70

[stingerdallas]

Any update on this? The workaround doesn't work if using the snapToInterval because its the last event that is correct. I can put in a debounce but it is way too long of a debounce since the onMomentumScrollEnd gets called almost a second apart.

When using snapToInterval, and user drags very little and lets go, it snaps back to the original snap location, but onMomentumScrollEnd gets called twice. once for the temp scrolled location and once for the new location

[kirx76]

Still an issue in version 0.71.7

[wyeo]

+1

[Jlexyc]

+1

[Bowlerr]

+1

[gaearon]

Looks like this will be fixed by https://github.com/facebook/react-native/pull/32433.

[gaearon]

Note there's a similar problem for onScrollBeginDrag (which gets called twice). I don't know if that PR fixes it.

[hichemfantar]

I'm still having this issue in react-native 0.72.6.

[hichemfantar]

Solution using useRef:

const canMomentum = React.useRef(false);

const onMomentumScrollBegin = () => {
  canMomentum.current = true;
};

const onMomentumScrollEnd = () => {
  if (canMomentum.current) {
    // console.log('onMomentumScrollEnd');
  }

  canMomentum.current = false;
};

return (
  <ScrollView
    onMomentumScrollBegin={onMomentumScrollBegin}
    onMomentumScrollEnd={onMomentumScrollEnd}
  ></ScrollView>
);

This works but the event is called too early, it doesn't wait for the animation to end.

[github-actions[bot]]

This issue is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[xaiamov]

It must be fixed in RN 0.74.1 https://github.com/facebook/react-native/commit/06668fcbacd750771f1d53cce829dc55e86f3f3c

[Iuriy-Budnikov]

Not fixed :(

[mars-lan]

Using RN 0.74.3 and can confirm that this issue has been fixed.