我有一個與我的REDX應用程序的問題:它正確地分派相關的動作和更新狀態,但由於某種原因,UI不會更新。 99%的問題似乎是由於國家實際上發生了變異而引起的,但我確信事實並非如此。以下是相關文件:React/Redux:儘管調度和狀態更改正確,但組件不會重繪。 (不涉及突變)
容器組件:
import React from 'react';
import { bindActionCreators } from 'redux';
import { connect } from 'react-redux';
import PropTypes from 'prop-types';
import requestEvents from 'actions/feedActions';
import { FeedElement, feedElementTypes } from '../components/feed/feedElement';
class Feed extends React.Component {
componentWillMount() {
this.props.requestEvents();
}
render() {
console.log('Rendering feed');
const listOfFeedElements = this.props.listOfFeedElements;
let elementsToDisplay;
if (listOfFeedElements.length === 0) {
elementsToDisplay = <li><p> No elements to display</p></li>;
} else {
const numOfElementsToDisplay = listOfFeedElements.length <= 10 ?
listOfFeedElements.length : 10;
const sortedElementsToDisplay = listOfFeedElements.concat().sort(
(e1, e2) => e1.timestamp - e2.timeStamp);
elementsToDisplay =
sortedElementsToDisplay
.slice(0, numOfElementsToDisplay)
.map(el => FeedElement(el));
}
return (
<div className="socialFeedContainer">
<h1> Social feed </h1>
<ol>
{elementsToDisplay}
</ol>
</div>
);
}
}
Feed.propTypes = {
requestEvents: PropTypes.func.isRequired,
listOfFeedElements: PropTypes.arrayOf(PropTypes.shape({
timeStamp: PropTypes.number.isRequired,
type: PropTypes.oneOf(Object.keys(feedElementTypes)).isRequired,
targetDeck: PropTypes.string.isRequired,
concernedUser: PropTypes.string.isRequired,
viewed: PropTypes.bool.isRequired })),
};
Feed.defaultProps = {
listOfFeedElements: [],
};
function mapDispatchToProps(dispatch) {
return bindActionCreators({ requestEvents }, dispatch);
}
function mapStateToProps(state) {
const { feedState } = state.local.feed.listOfFeedElements;
return {
feedState,
};
}
export default connect(mapStateToProps, mapDispatchToProps)(Feed);
減速:
import Immutable from 'seamless-immutable';
import { types } from 'actions/feedActions';
const initialState = Immutable({
listOfFeedElements: [],
sentRequestForList: false,
receivedList: false,
});
function feedReducer(state = initialState, action) {
switch (action.type) {
case types.REQUEST_FEED_ELEMENTS:
return Immutable.merge(state, {
sentRequestForList: true,
receivedList: false,
});
case types.RECEIVED_LIST:
return Immutable.merge(state, {
sentRequestForList: false,
receivedList: true,
listOfFeedElements: action.payload.listOfNotifications,
});
default:
return state;
}
}
export default feedReducer;
城:
import { takeLatest, put } from 'redux-saga/effects';
import { types } from 'actions/feedActions';
import feedApiCall from './feedApiCall';
export function* getFeedFlow() {
try {
console.log('sent request for feed');
const listOfNotifications = feedApiCall();
yield put({
type: types.RECEIVED_LIST,
payload: {
listOfNotifications,
},
});
} catch (error) {
yield put({
type: types.RECEPTION_ERROR,
payload: {
message: error.message,
statusCode: error.statusCode,
},
});
}
}
function* feedUpdateWatcher() {
yield takeLatest(types.REQUEST_FEED_ELEMENTS, getFeedFlow);
}
export default feedUpdateWatcher;
該操作得到調度和狀態修改(最後我有一個列表與組件)。然而,該組件只呈現一次,因爲我可以從調用console.log中檢查。
對於redux,我仍然生疏,但在您的mapStateToProps中,當組件呈現屬性listOfFeedElements時,您好像綁定了一個屬性'feedState'。 – Gimby
哪些操作被稱爲REQUEST_FEED_ELEMENTS或RECEIVED_LIST? –
@Gimby:很好,但這不是問題。 'console.log('Rendering feed');'只打印一次,這意味着渲染函數甚至不會被第二次調用。 – Gloomy