问题
My _loadMoreRows and _isRowLoaded are not getting called, so loadedRowsMap remains empty and I am unable to identify the rows loaded to avoid making HTTP request .
Here's my complete code :
import React, { Component } from 'react';
import { connect } from 'react-redux';
import {formatDate} from '../../helper/date';
import { recentActivitiAction } from '../actions/dashboardAction';
import { BeatLoader } from 'react-spinners';
import {AutoSizer, List, CellMeasurer, InfiniteLoader, CellMeasurerCache} from 'react-virtualized';
import styles from '../../css/AutoSizer.module.css';
import Skeleton from 'react-skeleton-loader';
const STATUS_LOADING = 1;
const STATUS_LOADED = 2;
const mapStateToProps = (state) => {
return {
recentActList: state.dashboardReducer.recentActList,
activitiLoading: state.dashboardReducer.activitiLoading
}
}
const mapDispatchToProps = (dispatch) => {
return {
getRecentActivites: (postData, callback) => {
dispatch(recentActivitiAction(postData, callback));
}
};
}
class RecentActivitiComp extends Component {
constructor(props) {
super(props);
this.state = {
loadedRowCount: 0,
loadedRowsMap: {},
loadingRowCount: 0,
};
this.cache = new CellMeasurerCache({
fixedWidth: true,
defaultHeight: 100
});
this._timeoutIdMap = {};
this._isRowLoaded = this._isRowLoaded.bind(this);
this._loadMoreRows = this._loadMoreRows.bind(this);
this.renderRow = this.renderRow.bind(this);
this.onRowsRendered = this.onRowsRendered.bind(this);
this.noRowsRenderer = this.noRowsRenderer.bind(this);
}
componentWillUnmount() {
Object.keys(this._timeoutIdMap).forEach(timeoutId => {
clearTimeout(timeoutId);
});
}
componentDidMount() {
var postData = {
"userName": "admin",
"queryType": "GET_RECENT_PROJECTS",
"data": {
pageStart: 1,
pageEnd: 20
}
};
this.props.getRecentActivites(postData, this.recentActResponse.bind(this));
}
updateDimensions() {
this.cache.clearAll();
this.activitiList.recomputeRowHeights();
}
recentActResponse(response) {
if (response.status === "FAILED") {
// handle error
}
}
_fieldGenerator(row, index) {
var formattedDate = formatDate(row.lastModified),
output = '', JSX = '';
if(formattedDate) {
formattedDate = formattedDate.split('-');
output = (
<div className="project-info-value byline">
<span>{formattedDate[0]}<sup>{formattedDate[1]}</sup> {formattedDate[2]} {formattedDate[3]}</span> by <a>{row.modifiedBy}</a>
</div>
)
} else {
output = (
<div className="project-info-value byline">
<span>Invalid Date by </span> <a>{row.modifiedBy}</a>
</div>
)
}
if(row.action === "upcoming-release") {
JSX =
<li key={index}>
<div className="block">
<div className="block_content">
<h2 className="title">{row.action}</h2>
{output}
<p className="excerpt">{row.notes}<a> Read More</a></p>
</div>
</div>
</li>
} else if(row.action === "created") {
JSX =
<li key={index}>
<div className="block">
<div className="block_content">
<h2 className="title">{row.type} <a>{row.name}</a> {row.action}</h2>
{output}
<p className="excerpt"></p>
</div>
</div>
</li>
} else if(row.action === "modified") {
JSX =
<li key={index}>
<div className="block">
<div className="block_content">
<h2 className="title">{row.type} <a>{row.name}</a> {row.action}</h2>
{output}
<p className="excerpt"></p>
</div>
</div>
</li>
} else {
JSX =
<li key={index}>
<div className="block">
<div className="block_content">
<h2 className="title"><a>{row.person}</a> added to <a>{row.addedTo}</a></h2>
{output}
<p className="excerpt"></p>
</div>
</div>
</li>
}
return JSX;
}
renderRow({ index, key, style, parent }) {
var JSX = '', content = '';
const list = this.props.recentActList
const {loadedRowsMap} = this.state;
if (loadedRowsMap[index] === STATUS_LOADED) {
const row = list[index];
JSX = this._fieldGenerator(row, index);
content = (
JSX
);
} else {
content = (
<div className={styles.placeholder} style={{width: 480}} />
);
}
return (
<CellMeasurer
cache={this.cache}
columnIndex={0}
key={key}
parent={parent}
rowIndex={index}
>
{({ measure }) => (
<div key={key} style={{...style}} onLoad={measure}>
{content}
</div>
)}
</CellMeasurer>
);
}
_isRowLoaded({index}) {
const {loadedRowsMap} = this.state;
return !!loadedRowsMap[index]; // STATUS_LOADING or STATUS_LOADED
}
_loadMoreRows({startIndex, stopIndex}) {
const {loadedRowsMap, loadingRowCount} = this.state;
const increment = stopIndex - startIndex + 1;
for (var i = startIndex; i <= stopIndex; i++) {
loadedRowsMap[i] = STATUS_LOADING;
}
this.setState({
loadingRowCount: loadingRowCount + increment,
});
const timeoutId = setTimeout(() => {
const {loadedRowCount, loadingRowCount} = this.state;
delete this._timeoutIdMap[timeoutId];
for (var i = startIndex; i <= stopIndex; i++) {
loadedRowsMap[i] = STATUS_LOADED;
}
this.setState({
loadingRowCount: loadingRowCount - increment,
loadedRowCount: loadedRowCount + increment,
});
promiseResolver();
}, 1000 + Math.round(Math.random() * 2000));
this._timeoutIdMap[timeoutId] = true;
let promiseResolver;
return new Promise(resolve => {
promiseResolver = resolve;
});
}
noRowsRenderer() {
return <div className={styles.noRows}>No rows</div>;
}
onRowsRendered({overscanStartIndex, overscanStopIndex, startIndex, stopIndex}) {
const list = this.props.recentActList.length ? this.props.recentActList : [];
const {loadedRowsMap} = this.state;
console.log(startIndex, stopIndex, this.state.loadedRowCount);
// if(startIndex + 10 === list.length && this._isRowLoaded(startIndex) !== STATUS_LOADED) {
// var postData = {
// "userName": "admin",
// "queryType": "GET_RECENT_PROJECTS",
// "data": {
// pageStart: 1,
// pageEnd: 10
// }
// };
// this.props.getRecentActivites(postData, this.recentActResponse.bind(this));
// }
}
render() {
const list = this.props.recentActList.length ? this.props.recentActList : [];
const {loadedRowCount, loadingRowCount} = this.state;
return (
<div className="recent left_panel">
<div className="x_panel">
<div className="x_title sub_title">
<h2>Recent Activites</h2>
</div>
<div className="x_content">
<div className="dashboard-widget-content">
<ul className="list-unstyled timeline widget">
<InfiniteLoader
isRowLoaded={this._isRowLoaded}
loadMoreRows={this._loadMoreRows}
rowCount={list.length}>
{({onRowsRendered, registerChild}) => (
<div className={styles.list}>
<AutoSizer onResize={this.updateDimensions.bind(this)}>
{({width, height}) => (
<List
ref={(ref) => {
this.activitiList = ref;
registerChild(ref);
}}
noRowsRenderer={this.noRowsRenderer}
onRowsRendered={this.onRowsRendered}
deferredMeasurementCache={this.cache}
width={width}
height={height}
deferredMeasurementCache={this.cache}
rowHeight={this.cache.rowHeight}
rowRenderer={this.renderRow}
rowCount={list.length} /* Initially render 20 records */
/>
)}
</AutoSizer>
</div>
)}
</InfiniteLoader>
</ul>
{/* <div className="align-right">
<a href="http://karthik.jivox.com/studio/eam/production/index.php#"
className="btn-jivox-1">
<span className="btn-icon">
<i className="fas fa-chevron-down" aria-hidden="true"></i>
</span> Show More Activities
</a>
</div> */}
</div>
</div>
</div>
</div>
);
}
}
const RecentActiviti = connect(mapStateToProps, mapDispatchToProps)(RecentActivitiComp);
export default RecentActiviti;
As you can see I am making API call at didMount phase and therefore populating my redux store with the data. Data is coming fine. But isRowLoaded and loadMoreRows are not getting called.
I have debugged the sample code of infiniteLoader.example.js, there during the inital render those two functions are called and properly set loadedRowsMap.
What I am doing wrong here ? :-( Any help would be greatly appreciated .
回答1:
(The code you've posted has a lot going on; you'll probably get better responses if you remove the parts that aren't related to your question.)
My advice is to take a look at the values you're getting for list.length, which you're passing to InfiniteLoader's rowCount prop. InfiniteLoader will only call loadMoreRows if rowCount is higher than the number of rows it has data for.
For example: during the first render, the value is 0, because you have not fetched any data yet. This prevents a call to loadMoreRows during the first render.
I also noticed that you are keeping loadedRowCount and loadingRowCount in state, but you never use them for anything. I don't think that's related to your issue, but it's also probably not intentional.
回答2:
I have resolved the issue after making some changes.
const mapStateToProps = (state) => {
return {
myList: state.dashboardReducer.myList
}
}
const list = this.props.myList.length ? this.props.recentActList : [];
const rowCount = list.length + (moreToBeLoaded ? 1 : 0);
To know why 1 more row loaded pls check this post react-virtualized InfiniteLoader/List - working example using AJAX
So the issue in my code was I was writing my custom onRowsRendered function and it was not handling the response correctly. Now I changed the code to use the one passed by InfiniteLoader.
Hope that helps.
<InfiniteLoader
isRowLoaded={this._isRowLoaded}
loadMoreRows={this._loadMoreRows}
rowCount={rowCount}>
{({onRowsRendered, registerChild}) => (
<div className={styles.list}>
<AutoSizer onResize={this.updateDimensions.bind(this)}>
{({width, height}) => (
<ActiviitiList
ref={(ref) => {
this.activitiList = ref;
registerChild(ref);
}}
width={width}
height={height}
onRowsRendered={onRowsRendered}
rowCount={rowCount}
rowHeight={this.cache.rowHeight}
rowRenderer={this._rowRenderer}
overscanRowCount={3}
deferredMeasurementCache={this.cache}
/>
)}
</AutoSizer>
</div>
)}
</InfiniteLoader>
来源：https://stackoverflow.com/questions/53446274/isrowloaded-and-loadmorerows-not-getting-called-react-virtualized