Joe Vilches
33bd90e07c
Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/50265 This is a fun one! "Improvements" consist of * Performance is better now. Previously we did a tree walk for each ID in the array, now its just one :) * Properly handles coopting (more on that below) **Performance** The previous implementation naively walked the tree until it found the right nativeId for each nativeId in the prop. This new algo just does a single tree walk and collects the views that have the right nativeIds as we are doing that walk. **Coopting** Our iOS code implements a form of accessibility coopting, where an element can "speak for" a descendant. This happens when some parent element does not have an accessibility label but a descendant does. We look at the subtree and grab every node that has a label and lift it up to the aforementioned element without a label. This enables some nice a11y features like wrapping `Text` in a `View` and letting the `View` just read all the `Text` inside (imagine a button with a label, you would only want to focus the button and just read the text instead of the text itself). This feature is nice but it becomes buggy when we introduce `accessibilityOrder`. Previously, there was no way to access nested elements on iOS, the platform prohibits this. However, you can get around this by using `accessibilityElements`, which our `accessibilityOrder` prop maps to. So you could define the order as `['parent', 'child']` and access both elements just fine. However, if that `parent` is a `View` that coopts `Text`, we have some issues. The `View` will read the `Text` but then when the user swipes we focus the `Text` and read it again! To get around this we check up the superview chain in RCTParagraphViewComponentView looking for Views that might coopt us and a cooresponding accessibilityElements with said candidates. If there is such a View we do not announce ourselves. Performance is iffy here, we need to iterate up to root for all text focusing, but this should be fairly fast for all intents and purposes and I have not noticed any lag when changing focus ordering. Changelog: [Internal] Reviewed By: jorge-cab Differential Revision: D71562476 fbshipit-source-id: 31fd935df0764459403464bd645aae2e664c69cb
React Native
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React Native brings React's declarative UI framework to iOS and Android. With React Native, you use native UI controls and have full access to the native platform.
- Declarative. React makes it painless to create interactive UIs. Declarative views make your code more predictable and easier to debug.
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Contents
- Requirements
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- Documentation
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- How to Contribute
- Code of Conduct
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📋 Requirements
React Native apps may target iOS 15.1 and Android 7.0 (API 24) or newer. You may use Windows, macOS, or Linux as your development operating system, though building and running iOS apps is limited to macOS. Tools like Expo can be used to work around this.
🎉 Building your first React Native app
Follow the Getting Started guide. The recommended way to install React Native depends on your project. Here you can find short guides for the most common scenarios:
📖 Documentation
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