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我發現嘗試使用react-router router.listen（...）獲取路由參數時失敗。通過使用window.location.pathname.split（'route /'）[1]，我可以得到參數。有小費嗎 ？react-router：從路由器偵聽事件獲取參數失敗
我一直在試圖弄清楚爲什麼會發生這種情況。到目前爲止，我注意到它在第一次路由更改（url更改）時失敗 - 我的意思是，通過使用，我的url從/param/y更改爲/param/x;但該參數僅在再次點擊時纔可用。我想這可能與我的行動或我的組件有關？或者聽衆被放置在反應生命週期中的哪個位置？
不知道我是否在錯誤的生命週期方法中聲明瞭eventlistener，或者;正如我一直在想的那樣，我將路由傳遞給Store，但我正在使用Router（Component）來處理這個事件。我想我需要使用redux的路由狀態。我想
具有監聽器組件：
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));
這裏的減速機：
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;
}
};
應用程序入口點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')
);
的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;