要在React Native中获取Victory区域图中按下的y轴值，可以使用Victory提供的onPress事件处理程序。

import React, { useState } from "react";
import { VictoryArea } from "victory-native";

const Chart = () => {
  const [yValue, setYValue] = useState(null);

  const handlePress = (event, props) => {
    const { y } = props.datum;
    setYValue(y);
  };

  return (
    <>
      <VictoryArea
        data={[
          { x: 1, y: 2 },
          { x: 2, y: 3 },
          { x: 3, y: 5 },
          { x: 4, y: 4 },
          { x: 5, y: 7 },
        ]}
        onPress={handlePress}
      />
      {yValue && <Text>Y value on press: {yValue}</Text>}
    </>
  );
};

export default Chart;