在react-google-maps中动态添加、更新、删除标记

Question

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import * as serviceWorker from './serviceWorker';
import { withScriptjs, withGoogleMap, GoogleMap, Marker } from "react-google-maps"


let markers = []

function createMarkers(numMarkers){

    for(let i = 0; i < numMarkers; i++){
        markers.push(<Marker key={i} position={{ lat: 45.123 + (i * 0.005), lng: -75.987 }} />)
    }

    return markers;
}

setInterval(function(){ 
  if(markers.length > 0 && markers[0].props.position){
    let marker = markers[0];
    //debugger;
    let position = marker.props.position;
    position.lat = position.lat - 0.005;
    position.lng = position.lng - 0.005;
    marker.props.position = position;
  }
}, 1000)

const MyGreatMap = withScriptjs( withGoogleMap(props => <GoogleMap
      defaultZoom={14}
      defaultCenter={{ lat: 45.123, lng: -75.978 }}
    >
      {createMarkers(10)}
    </GoogleMap>));


ReactDOM.render(
  <MyGreatMap 
    googleMapURL="https://maps.googleapis.com/maps/api/js?v=3.exp&libraries=geometry,drawing,places&key=AIzaSyDS-TFZqRfUx9xPXTJrPH6eml-gGo-btZ0"
    loadingElement={<div style={{ height: `100%` }} />}
    containerElement={<div style={{ height: `800px` }} />}
    mapElement={<div style={{ height: `100%` }} />}
  />, 
  document.getElementById('root'));

Answer 1

我确信这是错误的，它应该以某种方式更新状态，但标记中的LAT/LNG信息是道具。

没错，markers需要移动到本地状态，因此可以引入一个组件，该组件接受markers道具作为初始状态，然后状态更新如下：

class MapWithMarkers extends React.Component {
  constructor(props) {
    super(props);
    this.state= {markers: this.props.markers};   //1.initialize initial state from props
  }

  updateMarker() {
      this.setState(prevState => {
        const markers = [...prevState.markers];
        markers[index] = {lat: <val>, lng: <val>};
        return {markers};
     })
  }

  componentDidMount() {
    this.intervalId = setInterval(this.updateMarker.bind(this), 1000);
  }
  componentWillUnmount(){
    clearInterval(this.intervalId);
  }
  
  render() {
    return (
      <Map center={this.props.center} zoom={this.props.zoom} places={this.state.markers} />
    ); 
  }
}

演示