null is not an object (evaluating 'this._listRef.scrollToIndex')

[dnish]

Since switching from ListView to FlatList we're getting some errors like this:

null is not an object (evaluating 'this._listRef.scrollToIndex')

They happen rarely, but I could confirm that this also happened on one of my devices (OnePlus 3 with Android 7). The app shutted down after I've tried to open a view with a FlatList in it. Sadly I wasn't able to reproduce it.

This is the full output:

TypeError null is not an object (evaluating 'this._listRef.scrollToIndex') 
    index.android.bundle:207:2069 value
    index.android.bundle:817:11813 value
    index.android.bundle:817:3218 
    index.android.bundle:39:562 
    index.android.bundle:32:664 callTimer
    index.android.bundle:32:1084 callTimers
    index.android.bundle:30:3208 value
    index.android.bundle:30:959 
    index.android.bundle:30:2640 value
    index.android.bundle:30:931 value

Due to our logs it only happens on Android devices. We are on React Native 0.46 and react-navigation for our routes. Maybe the view is destroyed while RN tries to access this._listRef?

[charpeni]

@facebook-github-bot needs-repro

[facebook-github-bot]

Can you reproduce the issue using Snack? This step is necessary for people to be able to see and debug the issue being reported. See "How to Contribute".

[dnish]

@charpeni Does this really need a repo when it appears in the error logs of Bugsnag? I'm just wondering, when I take a look into

react-native/Libraries/Lists/FlatList.js

Line 395 in d1372fa

getScrollableNode() {

there are a checks for this._listRef.

 if (this._listRef) {
      return this._listRef.getScrollableNode();
}

But this check is missing in

react-native/Libraries/Lists/FlatList.js

Line 342 in d1372fa

this._listRef.scrollToIndex(params);

I guess there is a reason why we need to check for this._listRef in the other functions? So maybe someone forgot to check for it also in scrollToIndex.

[jasongrishkoff]

Also seeing this error pop up in my Android crash logs.

[pull-bot]

@facebook-github-bot no-template

[facebook-github-bot]

Hey, thanks for reporting this issue! It looks like your description is missing some necessary information, or the list of reproduction steps is not complete. Can you please add all the details specified in the Issue Template? This is necessary for people to be able to understand and reproduce the issue being reported. I am going to close this, but feel free to open a new issue with the additional information provided. Thanks! See "What to Expect from Maintainers" to learn more.

[DeividVeloso]

TypeError: null is not an object (evaluating 'this._listRef.scrollToOffset')
at scrollToOffset(app:///index.android.bundle:40893:20)
at ? (app:///index.android.bundle:79013:48)
at ? (app:///index.android.bundle:4153:24)
at _callTimer(app:///index.android.bundle:4074:15)
at callTimers(app:///index.android.bundle:4268:17)
at __callFunction(app:///index.android.bundle:3637:47)
at ? (app:///index.android.bundle:3453:29)
at __guard(app:///index.android.bundle:3608:11)
at callFunctionReturnFlushedQueue(app:///index.android.bundle:3452:20)

I have same issue

[est7]

@DeividVeloso did u solved it?

[DeividVeloso]

Not yet, some times ocorre.

Thanks