如何使用Apollo graphql实现react-sortable-hoc？

Question

Link with sample gif of issue here!

你好，我正在创建一个允许用户创建列表的应用程序（所有数据都存储在mongoDB上并可以通过Apollo GraphQL访问）；每个列表都有一个属性listItems，这是一个存储列表中所有项目的数组。

[当用户转到单独的Ranklist.js组件页面时，它将加载列表以及通过graphQL查询访问的所有列表项。

[此应用从此处利用react-sortable-hoc允许用户在其中移动列表项。尽管我能够移动listItems，但是一旦放开，页面就会重置顺序以匹配存储在mongoDB上的数组的顺序。

[请告知我为什么会这样，以及如何正确地实现一种方法，通过Apollo graphQL将react-sortable-hoc与数据库一起保存列表的顺序。

import React, { useContext, useRef, useState } from "react";
import gql from "graphql-tag";
import { useQuery, useMutation } from "@apollo/react-hooks";
import {
  Form,
} from "semantic-ui-react";
import moment from "moment";

import { AuthContext } from "../context/auth";
import { SortableContainer, SortableElement } from "react-sortable-hoc";
import arrayMove from "array-move";
import "../RankList.css";
import { CSSTransitionGroup } from "react-transition-group";

const SortableItem = SortableElement(({ value }) => (
  <li className="listLI">{value}</li>
));

const SortableList = SortableContainer(({ items }) => {
  return (
    <ol className="theList">
      <CSSTransitionGroup
        transitionName="ranklist"
        transitionEnterTimeout={500}
        transitionLeaveTimeout={300}
      >
        {items.map((item, index) => (
          <SortableItem
            key={`item-${item.id}`}
            index={index}
            value={item.body}
          />
        ))}
      </CSSTransitionGroup>
    </ol>
  );
});


function RankList(props) {
  const listId = props.match.params.listId;
  const { user } = useContext(AuthContext);
  const listItemInputRef = useRef(null);

  const [state, setState] = useState({ items: [] });
  const [listItem, setListItem] = useState("");

  const { loading, error, data } = useQuery(FETCH_LIST_QUERY, {
    variables: {
      listId,
    },
  });


  const [submitListItem] = useMutation(SUBMIT_LIST_ITEM_MUTATION, {
    update() {
      setListItem("");
      listItemInputRef.current.blur();
    },
    variables: {
      listId,
      body: listItem,
    },
  });

  if (loading) return <p>Loading...</p>;
  if (error) return <p>Error..</p>;

  function deleteListCallback() {
    props.history.push("/");
  }

  function onSortEnd({ oldIndex, newIndex }) {
    setState(({ items }) => ({
      items: arrayMove(items, oldIndex, newIndex),
    }));
  }

  let listMarkup;
  if (!data.getList) {
    listMarkup = <p>Loading list...</p>;
  } else {
    const {
      id,
      title,
      createdAt,
      username,
      listItems,
      comments,
      likes,
      likeCount,
      commentCount,
    } = data.getList;

    listMarkup = user ? (
      <div className="todoListMain">
        <div className="rankListMain">
          <div className="rankItemInput">
            <h3>{title}</h3>
            <Form>
              <div className="ui action input fluid">
                <input
                  type="text"
                  placeholder="Choose rank item.."
                  name="listItem"
                  value={listItem}
                  onChange={(event) => setListItem(event.target.value)}
                  ref={listItemInputRef}
                />
                <button
                  type="submit"
                  className="ui button teal"
                  disabled={listItem.trim() === ""}
                  onClick={submitListItem}
                >
                  Submit
                </button>
              </div>
            </Form>
          </div>
          <SortableList
            items={listItems}
            onSortEnd={onSortEnd}
            helperClass="helperLI"
          />
        </div>
      </div>
    ) : (
      <div className="todoListMain">
        <div className="rankListMain">
          <div className="rankItemInput">
            <h3>{props.title}</h3>
          </div>
          <SortableList
            items={listItems}
            onSortEnd={onSortEnd}
            helperClass="helperLI"
          />
        </div>
      </div>
    );
  }

  return listMarkup;
}



const SUBMIT_LIST_ITEM_MUTATION = gql`
  mutation($listId: ID!, $body: String!) {
    createListItem(listId: $listId, body: $body) {
      id
      listItems {
        id
        body
        createdAt
        username
      }
      comments {
        id
        body
        createdAt
        username
      }
      commentCount
    }
  }
`;

const FETCH_LIST_QUERY = gql`
  query($listId: ID!) {
    getList(listId: $listId) {
      id
      title
      createdAt
      username
      listItems {
        id
        createdAt
        username
        body
      }
      likeCount
      likes {
        username
      }
      commentCount
      comments {
        id
        username
        createdAt
        body
      }
    }
  }
`;

export default RankList;

Answer 1

您的onSortEnd函数调用setState并相应地更新state.items，但是您永远不会在组件中使用state.items，而是直接使用data.getList.listItems。由于该值在最初获取后不会更改，因此您的列表保持不变。

您应该改用state.items。然后，只要useEffect的值发生更改，就可以使用state.items更新listItems-例如，最初是在返回服务器的响应或响应突变时。类似于：

onEffect(() => {
  if (data && data.getList && data.getList.listItems) {
    setState(() => ({ items: data.getList.listItems }))
  }
}, [data])