b48f7e5605
Summary: This PR adds support for Animated tracking to Animated Native Driver implementation on Android and iOS. Animated tracking allows for animation to be started with a "dynamic" end value. Instead of passing a fixed number as end value we can pass a reference to another Animated.Value. Then when that value changes, the animation will be reconfigured to drive the animation to the new destination point. What is important is that animation will keep its state in the process of updating "toValue". That is if it is a spring animation and the end value changes while the previous animation still hasn't settled the new animation will start from the current position and will inherit current velocity. This makes end value transitions very smooth. Animated tracking is available in JS implementation of Animated library but not in the native implementation. Therefore until now, it wasn't possible to utilize native driver when using animated tracking. Offloading animation from JS thread turns out to be crucial for gesture driven animations. This PR is a step forward towards feature parity between JS and native implementations of Animated. Here is a link to example video that shows how tracking can be used to implement chat heads effect: https://twitter.com/kzzzf/status/958362032650244101 In addition this PR fixes an issue with frames animation driver on Android that because of rounding issues was taking one extra frame to start. Because of that change I had to update a number of Android unit tests that were relying on that behavior and running that one additional animation step prior to performing checks. As a part of this PR I'm adding three unit tests for each of the platforms that verifies most important aspects of this implementation. Please refer to the code and look at the test cases top level comments to learn what they do. I'm also adding a section to "Native Animated Example" screen in RNTester app that provides a test case for tracking. In the example we have blue square that fallows the red line drawn on screen. Line uses Animated.Value for it's position while square is connected via tracking spring animation to that value. So it is ought to follow the line. When user taps in the area surrounding the button new position for the red line is selected at random and the value updates. Then we can watch blue screen animate to that position. You can also refer to this video that I use to demonstrate how tracking can be linked with native gesture events using react-native-gesture-handler lib: https://twitter.com/kzzzf/status/958362032650244101 [GENERAL][FEATURE][Native Animated] - Added support for animated tracking to native driver. Now you can use `useNativeDriver` flag with animations that track other Animated.Values Closes https://github.com/facebook/react-native/pull/17896 Differential Revision: D6974170 Pulled By: hramos fbshipit-source-id: 50e918b36ee10f80c1deb866c955661d4cc2619b |
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| .. | ||
| RNTester | ||
| RNTester-tvOS | ||
| RNTester.xcodeproj | ||
| RNTesterIntegrationTests | ||
| RNTesterUnitTests | ||
| android/app | ||
| js | ||
| README.md | ||
README.md
RNTester
The RNTester showcases React Native views and modules.
Running this app
Before running the app, make sure you ran:
git clone https://github.com/facebook/react-native.git
cd react-native
npm install
Running on iOS
Mac OS and Xcode are required.
- Open
RNTester/RNTester.xcodeprojin Xcode - Hit the Run button
See Running on device if you want to use a physical device.
Running on Android
You'll need to have all the prerequisites (SDK, NDK) for Building React Native installed.
Start an Android emulator (Genymotion is recommended).
cd react-native
./gradlew :RNTester:android:app:installDebug
./scripts/packager.sh
Note: Building for the first time can take a while.
Open the RNTester app in your emulator.
See Running on Device in case you want to use a physical device.
Running with Buck
Follow the same setup as running with gradle.
Install Buck from here.
Run the following commands from the react-native folder:
./gradlew :ReactAndroid:packageReactNdkLibsForBuck
buck fetch rntester
buck install -r rntester
./scripts/packager.sh
Note: The native libs are still built using gradle. Full build with buck is coming soon(tm).
Built from source
Building the app on both iOS and Android means building the React Native framework from source. This way you're running the latest native and JS code the way you see it in your clone of the github repo.
This is different from apps created using react-native init which have a dependency on a specific version of React Native JS and native code, declared in a package.json file (and build.gradle for Android apps).