Javascript 无法处理状态'；装载'；适当地与redux反应

嘿，伙计们刚刚转到redux，所以在react中，我所做的是在componentDidMount（）中，我调用api，当我收到数据时，我将加载设置为false（最初加载为true），以摆脱“react微调器”

但是在componentDidMount（）中使用redux之后，我正在调用另一个中的action creater，在那里我正在接收数据，那么我如何管理这里的“加载”？我是否可以通过某种方式将某个东西从action creater传递到触发状态并将加载设置为false的组件？或者还有其他的方法吗？你们都是如何管理的

这是我的密码

Home.js

class home extends Component {
  UNSAFE_componentWillMount() {
    this.props.verifyToken();
  }

  componentDidMount() {
    this.props.categoryAction();

  }
  constructor(props) {
    super(props);
    this.state = {
      categoriesWithTheirImages: [],
      displayToggle: false,
      loading: false,
    };
  }


  renderCategory = () => {

    return this.props.allCategories.map((item) => {
      return (
        <div
          className="category_div"
          key={item._id}
          onClick={() => this.setState({ displayToggle: true })}
        >
          <img
            src={item.image}
            alt="miss-mistake"
            className="category_image_home"
          />
          <span className="category_heading_home">{item.categoryName}</span>
        </div>
      );
    });

  };

  render() {

    if (this.state.loading) {
      return (
        <div className="sweet-loading-main">
          <FadeLoader
            css={override}
            sizeUnit={"px"}
            size={50}
            color={"#ff9d72"}
            loading={this.state.loading}
          />
        </div>
      );
    } else {
      console.log(this.props.allCategories);
      return (
        <React.Fragment>
          {/* <Fade left> */}
          <Header />
          <div className="main_content_homepage">
            <p className="category_select">Please select a category</p>
            <div className="category_list">{this.renderCategory()}</div>
          </div>
          {this.renderStoryActionDialog()}
          {/* </Fade> */}
        </React.Fragment>
      );
    }
  }
}


const mapStateToProps = (state) => {
  console.log(state);
  const images = [family, ring, beer, feedback, academic];
  let categoriesWithImages = state.getCategoryReducer.map((item, index) => {
    item.image = images[index];
    return item;
  });
  console.log(categoriesWithImages);
  return { allCategories: categoriesWithImages };
};
export default connect(mapStateToProps, { verifyToken, categoryAction })(home);

减速器锉

import { USER, CATEGORY} from "../actionTypes";
const getCategoryReducer = (state = [], action) => {

  switch (action.type) {
    case CATEGORY:
      return action.payload;
    default:
      return state;
  }

};

export default getCategoryReducer;

---

您应该在

reducer

文件中处理加载状态。目前，它是在您的

组件

文件中定义的。例如，当您发送操作时，它也应该更新您的加载状态。我会做类似的事情

import { USER, FETCH_CATEGORY, FETCH_CATEGORY_SUCCESS, FETCH_CATEGORY_FAIL} from "../actionTypes";
const INITIAL_STATE = {
    loading: false,
    err: false,
    data: []
}
const getCategoryReducer = (state = INITIAL_STATE, action) => {

  switch (action.type) {
    case FETCH_CATEGORY:
       return Object.assign({}, state, {
            loading: true,
            data: [],
        })

      case FETCH_CATEGORY_SUCCESS
          return Object.assign({}, state, {
            loading: false,
            data: action.payload,
        })

       case FETCH_CATEGORY_FAIL
          return Object.assign({}, state, {
            loading: false,
            data: action.payload,
            err: true
        })

    default:
      return state;
  }

};

export default getCategoryReducer;

你的动作文件看起来像这样

import { FETCH_CATEGORY, FETCH_CATEGORY_SUCCESS, FETCH_CATEGORY_FAIL } from "../actionTypes";
export const categoryAction = ()=> {
  //setting loading to true
  return dispatch => {
    dispatch({ type: FETCH_CATEGORY });
    fetch("http://localhost:3000/api/get_categories", {
      method: "GET",
    }).then(res=>res.json())
      .then(response => {
         //setting loading to false
        dispatch({ type: FETCH_CATEGORY_SUCCESS, payload: response });
      })
      .catch(err => console.log("Eror in adding", err);  dispatch({ type: FETCH_CATEGORY_FAIL, payload: err }););
  };
};

---

然后，您可以在您的

Home.js

中阅读加载道具，我通常也会在我的redux存储中保持加载状态，因此当您完成加载后，您可以发送一个

LOADED

操作。另一种选择是根据

allCategories

道具中是否有任何内容，在组件中加载

。
import { FETCH_CATEGORY, FETCH_CATEGORY_SUCCESS, FETCH_CATEGORY_FAIL } from "../actionTypes";
export const categoryAction = ()=> {
  //setting loading to true
  return dispatch => {
    dispatch({ type: FETCH_CATEGORY });
    fetch("http://localhost:3000/api/get_categories", {
      method: "GET",
    }).then(res=>res.json())
      .then(response => {
         //setting loading to false
        dispatch({ type: FETCH_CATEGORY_SUCCESS, payload: response });
      })
      .catch(err => console.log("Eror in adding", err);  dispatch({ type: FETCH_CATEGORY_FAIL, payload: err }););
  };
};