react / react/react-native

<View /> doesn't recalculate it's size when a descendant <Text /> changes height due to wrapping following a device rotation

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Beschreibung

🐛 Bug Report

I believe I've found a bug in the View size calculation logic in React Native. In certain cases, the ancestor View fails to recalculate its size if a descendant <Text /> component changes in size due to a rotation and subsequent text (re)wrapping.

The following shows three states: initial, rotated, and back to original orientation. Notice that the fuschia view "grows" after returning to the original orientation.

Initial orientation
image
Portrait
image
Back to initial orientation
image

Speculative Analysis and Workaround

This appears to be an issue where an ancestor view caches a layout calculation and doesn't trigger a re-calculation when a nested Text component changes in size due to orientation changes.

After some playing around, we've figured out that if you "poke" any of the style properties that affect the view's style layout, the view will recalculate and be correct. We did this by toggling a state var upon rotation and then adding/removing a style object to the view's styles array that contained an extra paddingBottom that mirrored the existing padding on the view (basically we changed the style but the effect had no changes to the layout).

You can see a demo of the workaround by uncommenting the line of code below the FIXME comment in the code sample.

To Reproduce

See the code, but basically if you have a <ScrollView> that contains a container <View> which contains another <View> and then have a <Text> element inside that view... this layout bug will happen. I haven't been able to reduce this example further than that.

Expected Behavior

After rotating and going back to the initial orientation, the View should be exactly the same size.

Code Example

Github repo: https://github.com/jeremywiebe/react-native-text-orientation-bug

Environment

  React Native Environment Info:
    System:
      OS: macOS 10.14.2
      CPU: (8) x64 Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
      Memory: 34.97 MB / 16.00 GB
      Shell: 3.0.0 - /usr/local/bin/fish
    Binaries:
      Node: 8.15.0 - /usr/local/bin/node
      Yarn: 1.13.0 - /usr/local/bin/yarn
      npm: 6.4.1 - /usr/local/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1
      Android SDK:
        API Levels: 23, 25, 27
        Build Tools: 23.0.1, 25.0.0, 25.0.2, 25.0.3, 27.0.3, 28.0.1, 28.0.2, 28.0.3
        System Images: android-16 | Intel x86 Atom, android-16 | Google APIs Intel x86 Atom, android-19 | Intel x86 Atom, android-19 | Google APIs Intel x86 Atom, android-23 | Google APIs Intel x86 Atom_64, android-24 | Google APIs Intel x86 Atom, android-24 | Google Play Intel x86 Atom, android-25 | Google APIs Intel x86 Atom, android-28 | Google Play Intel x86 Atom
    IDEs:
      Android Studio: 3.1 AI-173.4907809
      Xcode: 10.1/10B61 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.6.3 => 16.6.3 
      react-native: 0.58.4 => 0.58.4 

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Erste Schritte

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  3. Forke das Repository und arbeite in einem Branch.
  4. Öffne einen Pull Request, der die Issue-Nummer nennt.

Rechercherichtung

Beginne mit dem verlinkten Reproduktions-Repository und reproduziere die Rotationssequenz mit ScrollView, verschachtelten View-Komponenten und dem Textumbruch von Text. Lies die im Bericht beschriebene Logik zur Größenberechnung von View und vergleiche die anfängliche, die Hochformat- und die wiederhergestellte Ausrichtung. Als erledigt gilt die Aufgabe, wenn der übergeordnete View ohne den Workaround zur Stiländerung exakt dieselbe Größe wieder annimmt.

Vom Indexierungsmodell aus dem Issue-Text verfasst.

Bewertung

Tech-Stack
react-native
Bereich
mobile-dev
Issue-Typ
Bug
Schwierigkeit
4/5
Geschätzter Aufwand
3-5 Tage
Aktivitätsstatus
Veraltet
Klarheit
Größtenteils klar
Anfängerfreundlichkeit
35/100

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