react-pan-responder

Low level pan gesture responder React component for DOM. This library is highly inspired by React Native PanResponder.

Table of Contents

• Table of Contents
• Features
• Getting Started
  • Installation
  • Example
  • Demo
• Responder Lifecycle
• Responder Handlers
  • Event
  • GestureState
• Properties
  • onStartShouldSet
  • onStartShouldSetCapture
  • onMoveShouldSet
  • onMoveShouldSetCapture
  • onGrant
  • onReject
  • onStart
  • onMove
  • onEnd
  • onRelease
  • onTerminationRequest
  • onTerminate
  • touchAction
  • innerRef
• License

Features

• Provides gestureState helper object
• Reconciles several touches into a single gesture
• Reconciles move and end events outside target element
• Compatible with mouse event

Getting Started

Installation

$ yarn add @cantonjs/react-pan-responder

Example

import React, { Component } from 'react';
import PanResponder from '@cantonjs/react-pan-responder';

export default class MyApp extends Component {
  render() {
    <PanResponder
      onStartShouldSet={(event, gestureState) => true}
      onGrant={(event, gestureState) => {}}
      onMove={(event, gestureState) => {}}
      onRelease={(event, gestureState) => {}}
    >
      {(ref) =>
        <div ref={ref}>Awesome</div>
      }
    </PanResponder>
  }
}

Demo

https://cap32.github.io/react-pan-responder/

Responder Lifecycle

A view can become the touch responder by implementing the correct negotiation methods. There are two methods to ask the view if it wants to become responder:

• View.props.onStartShouldSet: (event, gestureState) => true, - Does this view want to become responder on the start of a touch?
• View.props.onMoveShouldSet: (event, gestureState) => true, - Called for every touch move on the View when it is not the responder: does this view want to "claim" touch responsiveness?

If the View returns true and attempts to become the responder, one of the following will happen:

• View.props.onGrant: (event, gestureState) => {} - The View is now responding for touch events. This is the time to highlight and show the user what is happening
• View.props.onReject: (event, gestureState) => {} - Something else is the responder right now and will not release it

If the view is responding, the following handlers can be called:

• View.props.onMove: (event, gestureState) => {} - The user is moving their finger
• View.props.onRelease: (event, gestureState) => {} - Fired at the end of the touch, i.e. "touchUp"
• View.props.onTerminationRequest: (event, gestureState) => true - Something else wants to become responder. Should this view release the responder? Returning true allows release
• View.props.onTerminate: (event, gestureState) => {} - The responder has been taken by other views after a call to onTerminationRequest

Responder Handlers

It provides a predictable wrapper of the responder handlers provided by the gesture responder system. For each handler, it provides a new gestureState object alongside the native event object:

onMove: (event, gestureState) => {}

Event

The native event that binding to window object. This is NOT a Synthetic Event

GestureState

A gestureState object has the following:

• stateID - ID of the gestureState- persisted as long as there at least one touch on screen
• moveX - the latest screen coordinates of the recently-moved touch
• moveY - the latest screen coordinates of the recently-moved touch
• x0 - the screen coordinates of the responder grant
• y0 - the screen coordinates of the responder grant
• dx - accumulated distance of the gesture since the touch started
• dy - accumulated distance of the gesture since the touch started
• vx - current velocity of the gesture
• vy - current velocity of the gesture
• numberActiveTouches - Number of touches currently on screen

Properties

All properties are optional

onStartShouldSet

boolean|function

Deciding this component to become responder on the start of a touch. Defaults to false. If giving a function, it should return a boolean.

onStartShouldSetCapture

boolean|function

Just like onStartShouldSet, but using capture. Defaults to false.

onMoveShouldSet

boolean|function

Deciding this component to become responder on every touch move on the View when it is not the responder. Defaults to false.

onMoveShouldSetCapture

boolean|function

Just like onMoveShouldSet, but using capture. Defaults to false.

onGrant

function

Fired when this component is now responding for touch events. This is the time to highlight and show the user what is happening.

onReject

function

Fired when something else is the responder right now and will not release it

onStart

function

Fired for every touch start when it is the responder.

onMove

function

Fired for every touch move when it is the responder.

onEnd

function

Fired for every touch end when it is the responder.

onRelease

function

Fired at the end of the touch, i.e. "touchUp".

onTerminationRequest

boolean|function

Fired when something else wants to become responder. Should this view release the responder? Returning true allows release.

onTerminate

function

Fired when responder has been taken by other views after a call to onTerminationRequest.

touchAction

string

Defining responder panning action. The value could be one of following string:

• none: Disable browser handling of all panning gestures (default).
• x: Enable single-finger horizontal panning gestures for browser handling.
• y: Enable single-finger vertical panning gestures for browser handling.

innerRef

function

Use this to access the internal component ref.

License

MIT