react / react/react-native

PanResponder onMoveShouldSetPanResponder delta not reset

Open
#46,837 10 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

API: PanResponder Issue: Author Provided Repro Needs: Attention Newer Patch Available
Dominant language
C++
Stars
127k
Forks
25.3k
Avg merge
1d 23h
Merged PRs (30d)
4

Description

Description

Delta is not reset between gestures when it returned false

PanResponder.create({
      onMoveShouldSetPanResponder(e, gesture) {
         const {dx, dy} = gesture
         return false
      },
})

That seems to be because none of the other callbacks are called and the inner state initial position isn't reset.

I'm currently fixing this with

function PanProvider({children}) {

 const capturedPositionRef = useRef(null);


   return <View onMoveShouldSetResponderCapture={({nativeEvent:{pageX, pageY}}) => {
     // don't do anything, just capture the initial position
     capturedPositionRef.current = {pageX, pageY}
      return false
  }}>
       <PanContext.Provider value={capturedPositionRef}>{children}</PanContext.Provider>
    </View>
}

export default function usePanResponderLock(direction: 'horizontal' | 'vertical') {
  // uses the provider initial position
  const captureGestureRef = usePanResponder();

  return useRef(
    PanResponder.create({
      onMoveShouldSetPanResponder({ nativeEvent: { pageX, pageY } }) {
        if (captureGestureRef.current) {
          const { pageX: startX, pageY: startY } = captureGestureRef.current;

          const dx = Math.abs(pageX - startX);
          const dy = Math.abs(pageY - startY);

          const dragging = dx > 2 || dy > 2;

          if (!dragging) return false;

          return direction === 'horizontal' ? dx > dy : dy > dx;
        }

        return false;
      },
      onPanResponderTerminationRequest() {
        return true;
      },
    }),
  ).current;
}

This is working well, but the delta should be fixed in RN

Steps to reproduce

Try looking for a horizontal gesture with dx > dy:

  • from the top left corner, make a vertical gesture => delta's are correct, view is not a responder.
  • make a new horizontal gesture from bottom left corner => delta y is the distance with the previous touch and delta x too => dy > dx even though it's a horizontal gesture
React Native Version

0.73.8

Affected Platforms

Runtime - Android

Output of npx react-native info
System:
  OS: macOS 14.5
  CPU: (12) arm64 Apple M2 Max
  Memory: 277.72 MB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 20.9.0
    path: ~/.nvm/versions/node/v20.9.0/bin/node
  Yarn:
    version: 1.22.19
    path: /usr/local/bin/yarn
  npm:
    version: 10.1.0
    path: ~/.nvm/versions/node/v20.9.0/bin/npm
  Watchman:
    version: 2024.01.22.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.13.0
    path: /usr/local/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.4
      - iOS 17.4
      - macOS 14.4
      - tvOS 17.4
      - visionOS 1.1
      - watchOS 10.4
  Android SDK: Not Found
IDEs:
  Android Studio: 2022.3 AI-223.8836.35.2231.10811636
  Xcode:
    version: 15.3/15E204a
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.11
    path: /usr/bin/javac
  Ruby:
    version: 3.3.0
    path: /Users/gregoirevda/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react: Not Found
  react-native: Not Found
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: Not found
  newArchEnabled: Not found
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found
Stacktrace or Logs
No stacktrace error.
Reproducer

https://snack.expo.dev/@gregoirevda/bad-orange-popsicle

Screenshots and Videos

No response

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Begin with the linked Snack reproducer and the PanResponder.create/onMoveShouldSetPanResponder path; trace how gesture deltas are initialized and retained when the callback returns false, focusing on Android. Done means a new gesture reports deltas from its own start even when the prior gesture never became a responder, with the reproducer behavior corrected.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react-native
Domain
mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.