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我在做什么：更改状态以响应用户的向上/向下滑动。环境：反应原生 0.61.5

我的组件如下。

import React, { useRef, useState } from 'react';
import { View, PanResponder } from 'react-native';

function SimpleWrapper(props) {
  const { children } = props;

  const [abc, setabc] = useState(0);

  console.log('SimpleWrapper', abc);

  const panResponder = useRef(
    PanResponder.create({
      onStartShouldSetPanResponder: (evt, gestureState) => handleShouldSetPanResponder(evt, gestureState),
      // onStartShouldSetPanResponderCapture: (evt, gestureState) => handleShouldSetPanResponder(evt, gestureState),
      onMoveShouldSetPanResponder: (evt, gestureState) => handleShouldSetPanResponder(evt, gestureState),
      // onMoveShouldSetPanResponderCapture: (evt, gestureState) => handleShouldSetPanResponder(evt, gestureState),
      // onPanResponderGrant: (evt, gestureState) => console.log('onPanResponderGrant', gestureState),
      onPanResponderMove: (evt, gestureState) => handleonPanResponderMove(evt, gestureState),
      onPanResponderTerminationRequest: () => {}
      // onPanResponderRelease: (evt, gestureState) => handlePanResponderRelease(evt, gestureState)
    })
  ).current;

  const handleShouldSetPanResponder = (evt, gestureState) => {
    const { dy } = gestureState;
    const isvalid = evt.nativeEvent.touches.length === 1 && Math.abs(dy) > gestureConfig.gestureIsClickThreshold;
    return isvalid;
  };

  const handleonPanResponderMove = (evt, gestureState) => {
    const { dy, vy } = gestureState;
    console.log('in handleonPanResponderMove:', abc, gestureState);
    if (dy < 0) {
      setabc(abc + 1);
    } else if (dy > 0) {
      setabc(abc - 1);
    }
    // }
  };

  return (
    <View {...panResponder.panHandlers} style={}>
      {children}
    </View>
  );
}

export default SimpleWrapper;

基本上我想增加/减少onMoveShouldSetPanResponder中的状态参数，

现在，在 onMoveShouldSetPanResponder 第一次触发时，'abc' 已成功递增/递减。组件中最顶层的控制台也显示了新值。

但是，在所有连续触发之后，onMoveShouldSetPanResponder 函数内的控制台始终将 abc 打印为0（即初始值）。它永远不会改变。

是不是我们无法访问 onMoveShouldSetPanResponder 内部的更新状态？我错过了什么还是有其他方法可以做到这一点？

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1 回答 1

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The abc variable is a stale closure you can pass a callback to a state setter: setabc(currentValue=>currentValue + 1);

于 2020-06-19T11:20:28.880 回答