我发现尝试使用react-router router.listen（...）获取route参数时失败。通过使用window.location.pathname.split（'route /'）[1]，我可以获得参数。有小费吗 ？
我一直在试图找出原因。到目前为止，我注意到它在第一次路由更改（URL更改）时失败-我的意思是，通过使用，我的URL从/param/y更改为/param/x；但该参数仅在再次单击时可用。我想这可能与我的动作或我的组件有关？还是在响应生命周期中将侦听器置于何处？
不知道我是在错误的生命周期方法中声明事件侦听器还是；正如我一直在想的那样，我正在将路由传递到Store，但是我认为此事件使用withRouter（Component）。我想我需要使用redux的路由状态。我想
具有侦听器的组件：
import React, { Component } from 'react';
import { connect } from 'react-redux';
import { withRouter } from 'react-router';
import { setActiveQuestion, setQuestionAnswer } from '../actions/index';
import { bindActionCreators } from 'redux';
import { Link } from 'react-router';
import Navbar from '../containers/navbar';
class Question extends Component {
constructor(props) {
super(props);
this.getClassName = this.getClassName.bind(this);
}
componentWillMount() {
this.setEventListeners();
}
setEventListeners() {
this.props.router.listen(() => {
// using location pathname instead, since props.params fail
//let question_id = this.props.params.question_id;
let question_id = window.location.pathname.split('question/')[1]
this.props.setActiveQuestion(question_id);
});
}
setAnswer(answer_id) {
let question_id = this.props.question.id;
this.props.setQuestionAnswer(question_id, answer_id);
}
getClassName(answers, item_answer_id) {
let classes = [];
// find the answer for the active question
let answer_index = _.findIndex(answers, (answer) => {
return answer.question_id === this.props.question.id;
});
// if there's no answer yet, skip class placement
if (answer_index === -1) {
return;
}
let answer = answers[answer_index];
// Test cases
const isUserCorrect = () => {
return answer.answer_id == answer.correct_answer_id && item_answer_id == answer.correct_answer_id
}
const isUserAnswer = () => {
return answer.answer_id === item_answer_id;
}
const isCorrectAnswer = () => {
return item_answer_id == answer.correct_answer_id;
}
// Test and set the correct case classname for styling
if (isUserCorrect()) {
classes.push('user_correct_answer');
}
if (isUserAnswer()) {
classes.push('user_answer');
}
if (isCorrectAnswer()) {
classes.push('correct_answer');
}
return classes.length > 0 ? classes.join(' ') : '';
}
answersList() {
return this.props.question.answers.map((answer) => {
return <li className={ this.getClassName(this.props.answers, answer.id) } key={ answer.id } onClick={ () => this.setAnswer(answer.id) }>{ answer.text }</li>
});
}
render() {
return (
<div>
<div className='question-container'>
<h2>{ this.props.question && this.props.question.question }</h2>
<ul>
{
this.props.question &&
this.answersList()
}
</ul>
</div>
<Navbar />
</div>
);
}
}
function mapStateToProps(state, ownProps) {
return {
question: state.questions.active,
answers: state.answers
}
}
function matchDispatchToProps(dispatch) {
return bindActionCreators({
setActiveQuestion: setActiveQuestion,
setQuestionAnswer: setQuestionAnswer
}, dispatch);
}
export default connect(mapStateToProps, matchDispatchToProps)(withRouter(Question));
这是减速器：
import { FETCH_QUESTIONS, SET_ACTIVE_QUESTION } from '../actions/index';
import _ from 'lodash';
const INITIAL_STATE = {
loading: true,
list: [],
active: 0
};
export default function(state = INITIAL_STATE, action) {
switch (action.type) {
case FETCH_QUESTIONS:
return Object.assign({}, state, {
loading: false,
list: action.payload
});
break;
case SET_ACTIVE_QUESTION:
// retrieve the active question by the route param `question id`
let question_id = parseInt(action.payload);
let question = _.find(state.list, function (question) {
return question.id === question_id;
});
return Object.assign({}, state, {
active: question
});
break;
default:
return state;
}
};
应用入口点index.js：
import React from 'react';
import ReactDOM from "react-dom";
import { Router, browserHistory } from 'react-router';
import { syncHistoryWithStore } from 'react-router-redux'
import { createStore, applyMiddleware } from 'redux';
import { Provider } from 'react-redux';
import routes from './config/routes';
import reducers from './reducers';
import promise from 'redux-promise';
const createStoreWithMiddleware = applyMiddleware(promise)(createStore);
const store = createStoreWithMiddleware(reducers);
const history = syncHistoryWithStore(browserHistory, store);
ReactDOM.render(
<Provider store={ store }>
<Router history={ history } routes={ routes } />
</Provider>,
document.getElementById('app')
);
router.js文件：
import { combineReducers } from 'redux';
import questionsReducer from './reducer_questions';
import answerReducer from './reducer_answers';
import { routerReducer } from 'react-router-redux'
const rootReducer = combineReducers({
questions: questionsReducer,
answers: answerReducer,
routing: routerReducer
});
export default rootReducer;
最佳答案
您可能不想看路由器，而是想看看withRotuer。
它将使您可以访问connect中的params对象。
withRouter(connect(function(state, props) {
return { question_id: props.params.question_id };
})(MyComponent)
然后您可以收听
componentDidMount/componentWillMount和componentWillReceiveProps(nextPropscomponentWillMount() {
this.props.setActiveQuestion(this.props.question_id);
}
componentWillReceiveProps(nextProps) {
if (this.props.question_id != nextProps.question_id) {
this.props.setActiveQuestion(nextProps.question_id);
}
}
现在，您的组件将无需了解react-router，并且具有更高的可重用性，加上当前的设置，您的组件将永远不会停止侦听可能导致问题的路由更改（因为缺少“
router.removeListner”）。可以在此处找到一个很好的视频，解释
withRouter关于javascript - react-router:从路由器监听事件获取参数失败，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/38986564/