如何将PanResponder与索引一起使用

import React, { Component } from 'react';
import { View, Text, PanResponder } from 'react-native';

class IndexedList extends Component {
  constructor(props) {
    super(props);
    this.state = {
      selectedIndex: null,
    };
    this.indexes = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'];
    this.indexPositions = {}; // 存储每个索引对应的位置信息
    this.panResponder = PanResponder.create({
      onStartShouldSetPanResponder: () => true,
      onPanResponderMove: (evt, gestureState) => {
        // 根据手势操作计算出选择的索引位置
        const { pageY } = evt.nativeEvent;
        const selectedIndex = this.calculateSelectedIndex(pageY);
        this.setState({ selectedIndex });
      },
      onPanResponderRelease: () => {
        // 处理手势释放事件
        const { selectedIndex } = this.state;
        // 根据索引位置滚动列表到相应位置
        this.scrollToIndex(selectedIndex);
      },
    });
  }

  componentDidMount() {
    // 计算每个索引对应的位置信息
    this.calculateIndexPositions();
  }

  calculateIndexPositions() {
    const { indexes } = this;
    const { height } = this.props;
    const indexHeight = height / indexes.length;
    let currentPosition = 0;
    indexes.forEach((index) => {
      this.indexPositions[index] = currentPosition;
      currentPosition += indexHeight;
    });
  }

  calculateSelectedIndex(pageY) {
    const { indexPositions } = this;
    const indexes = Object.keys(indexPositions);
    let selectedIndex = null;
    indexes.forEach((index) => {
      if (pageY >= indexPositions[index]) {
        selectedIndex = index;
      }
    });
    return selectedIndex;
  }

  scrollToIndex(index) {
    // 根据索引位置滚动列表到相应位置
    // TODO: 实现滚动逻辑
  }

  render() {
    const { selectedIndex } = this.state;
    return (
      <View style={{ flex: 1 }} {...this.panResponder.panHandlers}>
        {this.indexes.map((index) => (
          <Text key={index} style={{ backgroundColor: selectedIndex === index ? 'red' : 'transparent' }}>
            {index}
          </Text>
        ))}
      </View>
    );
  }
}

export default IndexedList;