React 更改 state 下一個組件

Question

我必須為輸入類型文件創建上傳文件唯一組件，因為我使用帶有拖放react-dropzone庫並在頁面中使用此組件 4 次。 最初，除了第一個組件，其他組件必須禁用，但加載文件后，下一個組件必須將 state 更改為 disable = {true}。如何正確實現使用 useState 的邏輯？

沙盒

上傳文件.js

const UploadFile = ({ visible }) => {
  const [active, setActive] = useState(false);

  useEffect(() => {
    if (!visible) {
      setActive(true);
    }
  }, [visible]);

  console.log(visible);

  const { getRootProps, getInputProps, open, acceptedFiles } = useDropzone({
    noClick: true,
    noKeyboard: true,
    disabled: active
  });

  const files = acceptedFiles.map((file) => (
    <li key={file.path}>
      {file.path} - {file.size} bytes
    </li>
  ));

  return (
    <>
      <div className="file-input">
        <div {...getRootProps({ className: "dropzone" })}>
          <input {...getInputProps()} />
          <p>Drag drop some files here</p>
          <button type="button" onClick={open} disabled={active}>
            Open File Dialog
          </button>
        </div>
        <aside>
          <h4>Files</h4>
          <ul>{files}</ul>
        </aside>
      </div>
    </>
  );
};

應用程序.js

export default function App() {
  return (
    <div className="App">
      <div className="upload-file">
        <h4>Please select file</h4>
        <div>
          <p>Images</p>
          <UploadFile visible />
          <UploadFile visible={false} />
        </div>
        <div>
          <p>Documents</p>
          <UploadFile visible={false} />
          <UploadFile visible={false} />
        </div>
        <br />
        <button type="submit" disabled={true}>
          SEND
        </button>
      </div>
    </div>
  );
}

Answer 1

你可以使用react context來創建各個組件之間的關系，並且在第一個文件drop之后，你可以go到upload組件的下一個索引

上傳文件.js

import React, { useEffect, useState, useContext } from "react";
import { useDropzone } from "react-dropzone";
import { DragContext } from "./App";

const UploadFile = ({ index = 0 }) => {
  const { currentIndex, setCurrentIndex } = useContext(DragContext); // use context
  const [active, setActive] = useState(false);

  useEffect(() => {
    if (index !== currentIndex) { // compare to active 
      setActive(true);
    } else {
      setActive(false);
    }
  }, [currentIndex, index]);

  console.log(active);

  const { getRootProps, getInputProps, open, acceptedFiles } = useDropzone({
    noClick: true,
    noKeyboard: true,
    disabled: active,
    onDropAccepted: () => {
      setCurrentIndex(currentIndex + 1);
    }
  });

  const files = acceptedFiles.map((file) => (
    <li key={file.path}>
      {file.path} - {file.size} bytes
    </li>
  ));

  return (
    <>
      <div className="file-input">
        <div {...getRootProps({ className: "dropzone" })}>
          <input {...getInputProps()} />
          <p>Drag drop some files here</p>
          <button type="button" onClick={open} disabled={active}>
            Open File Dialog
          </button>
        </div>
        <aside>
          <h4>Files</h4>
          <ul>{files}</ul>
        </aside>
      </div>
    </>
  );
};

export default UploadFile;

應用程序.js

import React, { createContext, useState } from "react";
import UploadFile from "./UploadFile";
import "./styles.css";

export const DragContext = createContext({});

export default function App() { 
  const [currentIndex, setCurrentIndex] = useState(0); // compare with index
  return (
    <div className="App">
      <DragContext.Provider value={{ currentIndex, setCurrentIndex }}>
        <div className="upload-file">
          <h4>Please select file</h4>
          <div>
            <p>Images</p>
            <UploadFile index={0} />
            <UploadFile index={1} />
          </div>
          <div>
            <p>Documents</p>
            <UploadFile index={2} />
            <UploadFile index={3} />
          </div>
          <br />
          <button type="submit" disabled={true}>
            SEND
          </button>
        </div>
      </DragContext.Provider>
    </div>
  );
}

Answer 2

您只能使用一個 state currentStep作為您父母的參考。

import React, { useCallback, useState } from "react";
import UploadFile from "./UploadFile";
import "./styles.css";

export default function App() {
  const [currentStep, setCurrentStep] = useState(1)
  const nextStep = useCallback(() => {setCurrentStep(crr => crr + 1)}, [])

  return (
    <div className="App">
      <div className="upload-file">
        <h4>Please select file</h4>
        <div>
          <p>Images</p>
          <UploadFile nextStep={nextStep} currentStep={currentStep} step={1} />
          <UploadFile nextStep={nextStep} currentStep={currentStep} step={2} />
        </div>
        <div>
          <p>Documents</p>
          <UploadFile nextStep={nextStep} currentStep={currentStep} step={3} />
          <UploadFile nextStep={nextStep} currentStep={currentStep} step={4} />
        </div>
        <br />
        <button type="submit" disabled={true}>
          SEND
        </button>
      </div>
    </div>
  );
}

在 Upload File 中您不需要 setState，只需將 step 與 currentStep 進行比較以檢查是否已啟用。 一旦接受 drop，您還需要檢查step === currentStep ，否則如果您對同一字段進行多次更改，將繼續打開其他字段。

import React from "react";
import { useDropzone } from "react-dropzone";

const UploadFile = ({ nextStep, step, currentStep }) => {
  const onDropAccepted = () => {
        if(step === currentStep) nextStep()
  }

  const { getRootProps, getInputProps, open, acceptedFiles } = useDropzone({
    noClick: true,
    noKeyboard: true,
    disabled: step > currentStep,
    onDropAccepted
  });

  const files = acceptedFiles.map((file) => (
    <li key={file.path}>
      {file.path} - {file.size} bytes
    </li>
  ));

  return (
    <>
      <div className="file-input">
        <div {...getRootProps({ className: "dropzone" })}>
          <input {...getInputProps()} />
          <p>Drag drop some files here</p>
          <button type="button" onClick={open} disabled={step > currentStep}>
            Open File Dialog
          </button>
        </div>
        <aside>
          <h4>Files</h4>
          <ul>{files}</ul>
        </aside>
      </div>
    </>
  );
};

export default UploadFile;