Rotating list view causes text to disappear and sometimes causes app to STB

[jaygarcia]

Rotating the list view causes the text to disappear. In some cases, the UIExplorer sample STBs.

Perhaps the Flex layout has something to do with it?

 row : {
        flexDirection   : 'row',
        justifyContent  : 'center',
        padding         : 10,
        backgroundColor : '#F6F6F6',
    },

My App:

UIExplorer:

[ustun]

I can confirm, the example UIExplorer project has the same bug.

[siuying]

Yep this happens.

[drkibitz]

Seeing this in my own layout:
contentContainer: position: 'absolute', left: 50, right: 50, top: 0, bottom: 0
contentColumns: flexDirection: 'row'
contentColumn: flexDirection: 'column', flex: 1
contentColumnText: ...text styles...

If I give contentContainer an explicit width disallowing anything to reflow, text remains visible.

Also if I give contentColumn the style of alignItems: 'flex-start' it allows the containers to reflow, but also prevents the text from wrapping, therefore the text remains visible here as well. This points to something specific in the text view...

Maybe is has to do specifically with alignItems: 'stretch' and the text view, because with this style the text continues to disappear? Just not sure though, these are all just assumptions at this point.

[drkibitz]

Also an important note:
This issue is not related to ListView, or ScrollView, it can be reproduced easily in any View.

[drkibitz]

Tracing things back to this commit 3f6943c, related to changes in Libraries/Text

[drkibitz]

Did some more digging, it looks like it is related to the NSLayoutManager losing it's reference to the NSTextStorage which results in NSLayoutManager returning an empty glyphRange in RCTText's drawRect method.

What's weird is when I compare _textStorage.layoutManagers[0] == _layoutManager I get true. But, _layerManager.textStorage is indeed nil. So the _layoutManager is added to _textStorage, but it does not have a reference back to the receiver, but I'm not sure how this happened.

NSLayoutManager.h says not to set layerManager.textStorage directly, but the funny thing is, when I do this exactly, e.g. _layoutManager.textStorage = _textStorage; inside drawRect, everything seems to work.

This seems like unexpected UIKit behavior to me, what does everyone else think?

[drkibitz]

Finally, I think I've got a fix, we were causing this error in RCTShadowText RCTMeasure function here https://github.com/facebook/react-native/blob/master/Libraries/Text/RCTShadowText.m#L28

Turns out, an NSLayoutManager allows, but does not work correctly when adding to more than one NSTextStorage receiver.

I think I've got a PR brewing I should make shortly.

[chirag04]

+1. Having the same issue. @vjeux