258 строки
9.2 KiB
JavaScript
258 строки
9.2 KiB
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow
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* @format
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*/
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'use strict';
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import type {PressEvent} from '../Types/CoreEventTypes';
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/**
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* `PanResponder` reconciles several touches into a single gesture. It makes
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* single-touch gestures resilient to extra touches, and can be used to
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* recognize simple multi-touch gestures.
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*
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* By default, `PanResponder` holds an `InteractionManager` handle to block
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* long-running JS events from interrupting active gestures.
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*
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* It provides a predictable wrapper of the responder handlers provided by the
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* [gesture responder system](docs/gesture-responder-system.html).
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* For each handler, it provides a new `gestureState` object alongside the
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* native event object:
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*
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* ```
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* onPanResponderMove: (event, gestureState) => {}
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* ```
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*
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* A native event is a synthetic touch event with the following form:
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*
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* - `nativeEvent`
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* + `changedTouches` - Array of all touch events that have changed since the last event
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* + `identifier` - The ID of the touch
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* + `locationX` - The X position of the touch, relative to the element
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* + `locationY` - The Y position of the touch, relative to the element
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* + `pageX` - The X position of the touch, relative to the root element
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* + `pageY` - The Y position of the touch, relative to the root element
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* + `target` - The node id of the element receiving the touch event
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* + `timestamp` - A time identifier for the touch, useful for velocity calculation
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* + `touches` - Array of all current touches on the screen
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*
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* A `gestureState` object has the following:
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*
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* - `stateID` - ID of the gestureState- persisted as long as there at least
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* one touch on screen
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* - `moveX` - the latest screen coordinates of the recently-moved touch
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* - `moveY` - the latest screen coordinates of the recently-moved touch
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* - `x0` - the screen coordinates of the responder grant
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* - `y0` - the screen coordinates of the responder grant
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* - `dx` - accumulated distance of the gesture since the touch started
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* - `dy` - accumulated distance of the gesture since the touch started
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* - `vx` - current velocity of the gesture
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* - `vy` - current velocity of the gesture
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* - `numberActiveTouches` - Number of touches currently on screen
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*
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* ### Basic Usage
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*
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* ```
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* componentWillMount: function() {
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* this._panResponder = PanResponder.create({
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* // Ask to be the responder:
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* onStartShouldSetPanResponder: (evt, gestureState) => true,
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* onStartShouldSetPanResponderCapture: (evt, gestureState) => true,
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* onMoveShouldSetPanResponder: (evt, gestureState) => true,
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* onMoveShouldSetPanResponderCapture: (evt, gestureState) => true,
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*
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* onPanResponderGrant: (evt, gestureState) => {
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* // The gesture has started. Show visual feedback so the user knows
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* // what is happening!
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*
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* // gestureState.d{x,y} will be set to zero now
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* },
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* onPanResponderMove: (evt, gestureState) => {
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* // The most recent move distance is gestureState.move{X,Y}
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*
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* // The accumulated gesture distance since becoming responder is
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* // gestureState.d{x,y}
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* },
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* onPanResponderTerminationRequest: (evt, gestureState) => true,
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* onPanResponderRelease: (evt, gestureState) => {
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* // The user has released all touches while this view is the
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* // responder. This typically means a gesture has succeeded
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* },
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* onPanResponderTerminate: (evt, gestureState) => {
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* // Another component has become the responder, so this gesture
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* // should be cancelled
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* },
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* onShouldBlockNativeResponder: (evt, gestureState) => {
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* // Returns whether this component should block native components from becoming the JS
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* // responder. Returns true by default. Is currently only supported on android.
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* return true;
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* },
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* });
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* },
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*
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* render: function() {
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* return (
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* <View {...this._panResponder.panHandlers} />
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* );
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* },
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*
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* ```
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*
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* ### Working Example
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*
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* To see it in action, try the
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* [PanResponder example in RNTester](https://github.com/facebook/react-native/blob/HEAD/packages/rn-tester/js/examples/PanResponder/PanResponderExample.js)
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*/
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export type GestureState = {|
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/**
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* ID of the gestureState - persisted as long as there at least one touch on screen
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*/
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stateID: number,
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/**
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* The latest screen coordinates of the recently-moved touch
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*/
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moveX: number,
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/**
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* The latest screen coordinates of the recently-moved touch
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*/
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moveY: number,
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/**
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* The screen coordinates of the responder grant
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*/
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x0: number,
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/**
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* The screen coordinates of the responder grant
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*/
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y0: number,
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/**
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* Accumulated distance of the gesture since the touch started
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*/
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dx: number,
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/**
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* Accumulated distance of the gesture since the touch started
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*/
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dy: number,
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/**
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* Current velocity of the gesture
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*/
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vx: number,
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/**
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* Current velocity of the gesture
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*/
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vy: number,
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/**
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* Number of touches currently on screen
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*/
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numberActiveTouches: number,
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/**
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* All `gestureState` accounts for timeStamps up until this value
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*
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* @private
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*/
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_accountsForMovesUpTo: number,
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|};
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type ActiveCallback = (
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event: PressEvent,
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gestureState: GestureState,
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) => boolean;
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type PassiveCallback = (event: PressEvent, gestureState: GestureState) => mixed;
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type PanHandlers = {|
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onMoveShouldSetResponder: (event: PressEvent) => boolean,
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onMoveShouldSetResponderCapture: (event: PressEvent) => boolean,
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onResponderEnd: (event: PressEvent) => void,
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onResponderGrant: (event: PressEvent) => boolean,
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onResponderMove: (event: PressEvent) => void,
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onResponderReject: (event: PressEvent) => void,
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onResponderRelease: (event: PressEvent) => void,
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onResponderStart: (event: PressEvent) => void,
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onResponderTerminate: (event: PressEvent) => void,
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onResponderTerminationRequest: (event: PressEvent) => boolean,
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onStartShouldSetResponder: (event: PressEvent) => boolean,
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onStartShouldSetResponderCapture: (event: PressEvent) => boolean,
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|};
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type PanResponderConfig = $ReadOnly<{|
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onMoveShouldSetPanResponder?: ?ActiveCallback,
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onMoveShouldSetPanResponderCapture?: ?ActiveCallback,
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onStartShouldSetPanResponder?: ?ActiveCallback,
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onStartShouldSetPanResponderCapture?: ?ActiveCallback,
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/**
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* The body of `onResponderGrant` returns a bool, but the vast majority of
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* callsites return void and this TODO notice is found in it:
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* TODO: t7467124 investigate if this can be removed
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*/
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onPanResponderGrant?: ?(PassiveCallback | ActiveCallback),
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onPanResponderReject?: ?PassiveCallback,
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onPanResponderStart?: ?PassiveCallback,
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onPanResponderEnd?: ?PassiveCallback,
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onPanResponderRelease?: ?PassiveCallback,
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onPanResponderMove?: ?PassiveCallback,
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onPanResponderTerminate?: ?PassiveCallback,
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onPanResponderTerminationRequest?: ?ActiveCallback,
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onShouldBlockNativeResponder?: ?ActiveCallback,
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|}>;
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export type PanResponderType = {
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_initializeGestureState: (gestureState: GestureState) => void,
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_updateGestureStateOnMove: (
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gestureState: GestureState,
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touchHistory: $PropertyType<PressEvent, 'touchHistory'>,
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) => void,
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/**
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* @param {object} config Enhanced versions of all of the responder callbacks
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* that provide not only the typical `ResponderSyntheticEvent`, but also the
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* `PanResponder` gesture state. Simply replace the word `Responder` with
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* `PanResponder` in each of the typical `onResponder*` callbacks. For
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* example, the `config` object would look like:
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*
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* - `onMoveShouldSetPanResponder: (e, gestureState) => {...}`
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* - `onMoveShouldSetPanResponderCapture: (e, gestureState) => {...}`
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* - `onStartShouldSetPanResponder: (e, gestureState) => {...}`
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* - `onStartShouldSetPanResponderCapture: (e, gestureState) => {...}`
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* - `onPanResponderReject: (e, gestureState) => {...}`
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* - `onPanResponderGrant: (e, gestureState) => {...}`
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* - `onPanResponderStart: (e, gestureState) => {...}`
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* - `onPanResponderEnd: (e, gestureState) => {...}`
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* - `onPanResponderRelease: (e, gestureState) => {...}`
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* - `onPanResponderMove: (e, gestureState) => {...}`
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* - `onPanResponderTerminate: (e, gestureState) => {...}`
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* - `onPanResponderTerminationRequest: (e, gestureState) => {...}`
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* - `onShouldBlockNativeResponder: (e, gestureState) => {...}`
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*
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* In general, for events that have capture equivalents, we update the
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* gestureState once in the capture phase and can use it in the bubble phase
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* as well.
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*
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* Be careful with onStartShould* callbacks. They only reflect updated
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* `gestureState` for start/end events that bubble/capture to the Node.
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* Once the node is the responder, you can rely on every start/end event
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* being processed by the gesture and `gestureState` being updated
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* accordingly. (numberActiveTouches) may not be totally accurate unless you
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* are the responder.
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*/
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create: (config: PanResponderConfig) => {
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getInteractionHandle: () => ?number,
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panHandlers: PanHandlers,
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},
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};
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