mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
Pavel Rotek
67be81968e
Summary:
React Native Environment Info:
System:
OS: Linux 4.15 Ubuntu 18.04.1 LTS (Bionic Beaver)
CPU: (4) x64 Intel(R) Core(TM) i5-7300U CPU @ 2.60GHz
Memory: 1.12 GB / 15.55 GB
Shell: 4.4.19 - /bin/bash
Binaries:
Node: 8.10.0 - /usr/bin/node
Yarn: 1.13.0 - /usr/local/bin/yarn
npm: 3.5.2 - /usr/bin/npm
SDKs:
Android SDK:
API Levels: 16, 19, 22, 23, 24, 25, 26, 27, 28
Build Tools: 23.0.1, 23.0.3, 25.0.0, 25.0.2, 25.0.3, 26.0.1, 26.0.3, 27.0.3, 28.0.2, 28.0.3
System Images: android-16 | Google APIs Intel x86 Atom, android-19 | Google APIs Intel x86 Atom, android-24 | Google Play Intel x86 Atom, android-27 | Google APIs Intel x86 Atom, android-28 | Intel x86 Atom_64, android-28 | Google APIs Intel x86 Atom, android-28 | Google Play Intel x86 Atom
npmPackages:
react: 16.8.6 => 16.8.6
react-native: git+https://github.com/facebook/react-native.git#v0.59.5 => 0.59.5
npmGlobalPackages:
react-native-cli: 2.0.1
react-native-git-upgrade: 0.2.7
The workaround implemented in https://github.com/facebook/react-native/pull/21117 tries to fix
https://issuetracker.google.com/issues/112385925 scroll direction (according to the latest comments, the scroll direction problem has been reverted in security patches so not sure if the workaround is still valid).
But... proposed solution in fling method is using signum which leads to zero computedVelocityY in case of zero mOnScrollDispatchHelper.getYFlingVelocity() on old devices(Samsung s4 mini) even when real velocityY is non zero
```
final int correctedVelocityY = (int)(Math.abs(velocityY) * Math.signum(mOnScrollDispatchHelper.getYFlingVelocity()));
```
Proposed solution is to take signum from original velocityY in case of zero
```
float signum = Math.signum(mOnScrollDispatchHelper.getYFlingVelocity());
if (signum == 0) {
signum = Math.signum(velocityY);
}
final int correctedVelocityY = (int)(Math.abs(velocityY) * signum);
```
The symptoms are the same as described in issue https://github.com/facebook/react-native/issues/22925, but proposed workaround doesn't work.
[Android][fixed] - Fix smooth scrolling on old devices (SDK >=16)
Pull Request resolved: https://github.com/facebook/react-native/pull/24545
Differential Revision: D15044834
Pulled By: cpojer
fbshipit-source-id: 3f523eb1a438df774e22387aecded433b9031ab9