如何使用Reaction中的上下文将数据从一个组件发送到另一个组件？

我需要将selectedCoin状态从Company发送到details.js 如何使用context执行此操作？

公司组件：

import React, { useState, useEffect } from "react";
import { Col, Image, Row } from "react-bootstrap";
import "./Company.scss";

// * api
import { getCoin } from "../services/api";

// *spinner
import Loader from "./Loader";

const Company = () => {
  const [selectedCoin, setSelectedCoin] = useState(null);
  const [coins, setCoins] = useState([]);

  useEffect(() => {
    const fetchAPI = async () => {
      const data = await getCoin();
      setCoins(data);
    };
    fetchAPI();
  }, []);

  const coinId = () => {
    console.log(selectedCoin);
  };

  coinId();

  return (
    <>
      {coins.length > 0 ? (
        coins.map((coin) => (
          <Row
            className={
              selectedCoin === coin.id
                ? "p-2 pe-3 border-top d-flex align-items-center company-list-single-active"
                : "p-2 border-top d-flex align-items-center company-list-single"
            }
            onClick={() => {
              setSelectedCoin(coin.id);
              // console.log(coin.id);
              // console.log(coin.name);
            }}
            key={coin.id}
          >
            <Col xxl="2" xl="2" lg="3" md="3" sm="2" xs="2">
              <Image
                src={coin.image}
                alt={coin.name}
                className="coin-image mx-2"
                fluid
              />
            </Col>
            <Col>
              <span>{coin.name}</span>
            </Col>
          </Row>
        ))
      ) : (
        <Loader />
      )}
    </>
  );
};
export default Company;

详细信息组件：

import React, { useState, useEffect } from "react";
import axios from "axios";

const Details = () => {
  const [data, setData] = useState({
    name: "",
    id: "",
  });

  const apiDetails = async () => {
    await axios
      .get(`https://api.coingecko.com/api/v3/coins/${"ethereum"}`)
      .then((r) => {
        // console.log(response);
        setData({
          name: r.data.name,
          id: r.data.id,
        });
        return setData;
      });
  };

  useEffect(() => {
    (async () => {
      const response = await apiDetails();
      setData({
        name: response.data.name,
        id: response.data.id,
      });
    })();
  }, []);

  return (
    <div>
      <h1>{data.name}</h1>
      <h1>{data.id}</h1>
    </div>
  );
};

export default Details;

---

解决方案

看起来您只是对代码感兴趣，所以我就把代码放在这里。 显然，感觉可以自由移动代码，并确保使用对您有意义的语法

这是上下文

CoinsContext.js

import React, { createContext, useContext, useState, useEffect } from "react";
import { getCoin } from "@api";

const CoinsContext = createContext({});

export const CoinsContextProvider = ({ children }) => {
  const [selectedCoin, setSelectedCoin] = useState(null);
  const [coins, setCoins] = useState([]);

  useEffect(() => {
    const fetchAPI = async () => {
      const data = await getCoin();
      setCoins(data);
    };
    fetchAPI();
  }, []);

  return (
    <CoinsContext.Provider value={{ selectedCoin, setSelectedCoin, coins }}>
      {children}
    </CoinsContext.Provider>
  );
};

export const useCoins = () => useContext(CoinsContext);

要使用它，您需要包装将要使用上下文的所有页面，例如，因为您希望Details.js和Company.js使用它，所以您需要用它包装这两个页面。 我只包装整个应用程序，这意味着整个应用程序都可以使用它，但是您可以随意做您想做的事情。

应该是这样的：

index.js

import React from "react";
import ReactDOM from "react-dom";
import App from "./App";

import { CoinsContextProvider } from "./CoinsContext";

ReactDOM.render(
  <React.StrictMode>
    <CoinsContextProvider>
      <App />
    </CoinsContextProvider>
  </React.StrictMode>,
  document.getElementById("root")
);

现在我们已经设置了CoinsContext，可以在您的组件上使用它

Company.js

import React from "react";
import { Col, Image, Row } from "react-bootstrap";
import "./Company.scss";

// *spinner
import Loader from "./Loader";
import { useCoins } from "./CoinsContext";

const Company = () => {
  const { coins, selectedCoin, setSelectedCoin } = useCoins();

  return (
    <>
      {coins.length > 0 ? (
        coins.map((coin) => (
          <Row
            className={
              selectedCoin === coin.id
                ? "p-2 pe-3 border-top d-flex align-items-center company-list-single-active"
                : "p-2 border-top d-flex align-items-center company-list-single"
            }
            onClick={() => {
              setSelectedCoin(coin.id);
              // console.log(coin.id);
              // console.log(coin.name);
            }}
            key={coin.id}
          >
            <Col xxl="2" xl="2" lg="3" md="3" sm="2" xs="2">
              <Image
                src={coin.image}
                alt={coin.name}
                className="coin-image mx-2"
                fluid
              />
            </Col>
            <Col>
              <span>{coin.name}</span>
            </Col>
          </Row>
        ))
      ) : (
        <Loader />
      )}
    </>
  );
};
export default Company;

Details.js

import React, { useState, useEffect } from "react";
import axios from "axios";

import { useCoins } from "./CoinsContext";

const Details = () => {
  const { selectedCoin, coins, setSelectedCoin } = useCoins();
  
  const [data, setData] = useState({
    name: "",
    id: "",
  });


  const apiDetails = async () => {
    await axios
      .get(`https://api.coingecko.com/api/v3/coins/${"ethereum"}`)
      .then((r) => {
        // console.log(response);
        setData({
          name: r.data.name,
          id: r.data.id,
        });
        return setData;
      });
  };

  useEffect(() => {
    (async () => {
      const response = await apiDetails();
      setData({
        name: response.data.name,
        id: response.data.id,
      });
    })();
  }, []);

  return (
    <div>
      <h1>{data.name}</h1>
      <h1>{data.id}</h1>
    </div>
  );
};

export default Details;

我们就完事了！现在，您不仅在组件之间共享selectedCoin，而且还将所有硬币提取逻辑放在您的上下文中，这总体上是正确的操作