[Android] ScrollView is missing initial scroll position for Android

[bcalik]

ScrollView has a contentOffset prop for iOS, which sets the initial scroll offset.
But it lacks on Android, so you can not set the initial scroll position.

For anyone who can make this, these are the attributes in Android's native ScrollView.

android:scrollX     The initial horizontal scroll offset, in pixels. 
android:scrollY     The initial vertical scroll offset, in pixels. 

[hufeng]

render() {
  return (
    <ScrollView ref={(view) => this._scrollView = view}>
    </ScrollView>
  );
}

this._scrollView.getScrollResponder().scrollTo({x: 0, y: 0, animated: true})

[bcalik]

@hufeng That will cause flickering after render, first you will see the 0,0 position, then it will scroll.

Also if you are using a ListView, then you will have to render all the data until the scroll position you want, then you can scroll there.. Which will slow your app dramatically.
But in iOS, you can just set initialListSize={1} and it can just start rendering where-ever you want by setting contentOffset.

[mangogogos]

https://productpains.com/post/react-native/content-offsetinset-for-scrollview

I started a product pains post for this a while back, but it hasn't gained any traction. While @hufeng's approach does the correct thing, it's very janky and even if you set animated: false, it will be noticeable to the end-user that the scrollview is jumping to its initial position. I've wanted to take a crack at a PR for this for a while but haven't had the bandwidth outside of work but for me this would be one of the most welcomed features for Android/iOS parity

[madox2]

When I try to call scrollTo from componentDidMount method it does not scroll. I have to use workaround with setTimeout to make it work:

componentDidMount() {
  setTimeout(() => this.refs._scrollView.scrollTo({ x: 100, y: 0 }) , 0);
}

[satya164]

It'll be awesome if someone could send a pull request for it.

[bcalik]

@madox2 Because the scroll position you want to scroll is not rendered yet, you have to wait for all rows to be rendered before you scroll to that position. So setTimeout is not a solution, which may not work.

iOS ListView does't have this issue, because it has a initial scroll position property, so it can start rendering from that position, not from zero.

[mkonicek]

Hi there! This issue is being closed because it has been inactive for a while.

But don't worry, it will live on with ProductPains! Check out its new home: https://productpains.com/post/react-native/android-scrollview-is-missing-initial-scroll-position-for-android

Product Pains has been very useful in highlighting the top bugs and feature requests:
https://productpains.com/product/react-native?tab=top

Also, if this issue is a bug, please consider sending a pull request with a fix.

[arv]

Was this fixed or just closed?

The productpain page links back to this issue.

[uqix]

+1

[cherniv]

+1 , please

[aymericbouzy]

+1

[satya164]

If someone is willing to send a PR, please do