在 React + Redux 中 Action 不会触发 reducer

Question

我正在开发一个 react-redux 应用程序，由于某种原因，我调用的操作没有到达 reducer（我目前只有一个 log 语句）。我附上了我认为相关的代码，任何贡献都将受到高度赞赏。

在组件的函数内调用的动作：

onSearchPressed() {
    console.log('search pressed');
    this.props.addToSaved();
}

actions/index.js:

var actions = exports = module.exports

exports.ADD_SAVED = "ADD_SAVED";

exports.addToSaved = function addToSaved() {
  console.log('got to ADD_SAVED step 2');
  return {
    type: actions.ADD_SAVED
  }
}

reducers/items.js：

const {
  ADD_SAVED
} = require('../actions/index')

const initialState = {
    savedList: []
}

module.exports = function items(state = initialState, action) {
    let list

    switch (action.type) {
        case ADD_SAVED:
            console.log('GOT to Step 3');
            return state;
        default:
            console.log('got to default');
            return state;
    }
}

reducers/index.js：

const { combineReducers } = require('redux')
const items = require('./items')

const rootReducer = combineReducers({
  items: items
})

module.exports = rootReducer

存储/配置存储.js：

import { createStore } from 'redux'
import rootReducer from '../reducers'

let store = createStore(rootReducer)

编辑：onSearchPressed 的整个组件：

class MainView extends Component {
    onSearchPressed() {
        this.props.addToSaved();
    }
    render() {
        console.log('MainView clicked');
        var property = this.props.property;

        return (
            <View style={styles.container}>
                <Image style={styles.image}
                    source={{uri: property.img_url}} />
                <Text style={styles.description}>{property.summary}</Text>
                <TouchableHighlight style = {styles.button}
                        onPress={this.onSearchPressed.bind(this)}
                        underlayColor='#99d9f4'>
                        <Text style = {styles.buttonText}>Save</Text>
                    </TouchableHighlight>
            </View>
        );
    }
}

module.exports = MainView;

Answer 1

正如 Rick Jolly 在您的问题的 cmets 中提到的那样，您的 onSearchPressed() 函数实际上并没有调度该动作，因为 addToSaved() 只是返回一个动作对象 - 它不调度任何东西。

如果你想从一个组件派发动作，你应该使用react-redux 将你的组件连接到redux。例如：

const { connect } = require('react-redux')

class MainView extends Component {
  onSearchPressed() {
    this.props.dispatchAddToSaved();
  }
  render() {...}
}

const mapDispatchToProps = (dispatch) => {
  return {
    dispatchAddToSaved: () => dispatch(addToSaved())
  }
}

module.exports = connect(null, mapDispatchToProps)(MainView)

请参阅'Usage With React' section of the Redux docs 了解更多信息。

Answer 2

最近我遇到了这样的问题，发现我使用了动作导入，但它必须来自道具。查看 toggleAddContactModal 的所有用法。就我而言，我错过了导致此问题的解构语句中的 toggleAddContactModal。

import React from 'react'
import ReactDOM from 'react-dom'
import Modal from 'react-modal'
import { bindActionCreators } from 'redux'
import { connect } from 'react-redux'
import {
  fetchContacts,
  addContact,
  toggleAddContactModal
} from '../../modules/contacts'
import ContactList from "../../components/contactList";

Modal.setAppElement('#root')

class Contacts extends React.Component {
  componentDidMount(){
    this.props.fetchContacts();
  }
  render(){
    const {fetchContacts, isFetching, contacts, 
      error, isAdding, addContact, isRegisterModalOpen,
      toggleAddContactModal} = this.props;
    let firstName;
    let lastName;
    const handleAddContact = (e) => {
      e.preventDefault();
      if (!firstName.value.trim() || !lastName.value.trim()) {
        return
      }
      addContact({ firstName : firstName.value, lastName: lastName.value});
    };

    return (
      <div>
        <h1>Contacts</h1>
        <div>
          <button onClick={fetchContacts} disabled={isFetching}>
            Get contacts
          </button>
          <button onClick={toggleAddContactModal}>
            Add contact
          </button>
        </div>
        <Modal isOpen={isRegisterModalOpen} onRequestClose={toggleAddContactModal}>
          <input type="text" name="firstName" placeholder="First name" ref={node =>         
 (firstName = node)} ></input>
      <input type="text" name="lastName" placeholder="Last name" ref={node => 
(lastName = node)} ></input>
          <button onClick={handleAddContact} disabled={isAdding}>
            Save
          </button>
        </Modal>
        <p>{error}</p>
        <p>Total {contacts.length} contacts</p>
        <div>
          <ContactList contacts={contacts} />
        </div>
      </div>
    );
  }
}
const mapStateToProps = ({ contactInfo }) => {
  console.log(contactInfo)
  return ({
    isAdding: contactInfo.isAdding,
    error: contactInfo.error,
    contacts: contactInfo.contacts,
    isFetching: contactInfo.isFetching,
    isRegisterModalOpen: contactInfo.isRegisterModalOpen
  });
}

const mapDispatchToProps = dispatch =>
  bindActionCreators(
    {
      fetchContacts,
      addContact,
      toggleAddContactModal
    },
    dispatch
  )

export default connect(
  mapStateToProps,
  mapDispatchToProps
)(Contacts)