react-google-maps/api DirectionsService 不断重新呈现自身

Question

我已经在 React JS 中编写了这段代码，以使用“react-google-maps/api”来计算两点之间的路线。现在我的 google 地图不断重新渲染，直到出现“DIRECTIONS_ROUTE: OVER_QUERY_LIMIT”错误。我不知道出了什么问题。帮助将不胜感激，因为我是 React 和 google-API 的初学者，而且我还没有在 React 中找到很多 google API 的指南。

这是我的代码：

import React from "react";
import {
  GoogleMap,
  useLoadScript,
  DirectionsService,
  DirectionsRenderer,
} from "@react-google-maps/api";

const libraries = ["places", "directions"];
const mapContainerStyle = {
  width: "100%",
  height: "50vh",
};
const center = {
  lat: 31.582045,
  lng: 74.329376,
};
const options = {};

const MainMaps = () => {
  const { isLoaded, loadError } = useLoadScript({
    googleMapsApiKey: "********",
    libraries,
  });

  const [origin2, setOrigin2] = React.useState("lahore");
  const [destination2, setDestination2] = React.useState("gujranwala");
  const [response, setResponse] = React.useState(null);

  const directionsCallback = (response) => {
    console.log(response);

    if (response !== null) {
      if (response.status === "OK") {
        setResponse(response);
      } else {
        console.log("response: ", response);
      }
    }
  };

  const mapRef = React.useRef();
  const onMapLoad = React.useCallback((map) => {
    mapRef.current = map;
  }, []);
  if (loadError) return "Error loading maps";
  if (!isLoaded) return "loading maps";

  const DirectionsServiceOption = {
    destination: destination2,
    origin: origin2,
    travelMode: "DRIVING",
  };

  return (
    <div>
      <GoogleMap
        mapContainerStyle={mapContainerStyle}
        zoom={8}
        center={center}
        onLoad={onMapLoad}
      >
        {response !== null && (
          <DirectionsRenderer
            options={{
              directions: response,
            }}
          />
        )}

        <DirectionsService
          options={DirectionsServiceOption}
          callback={directionsCallback}
        />
      </GoogleMap>
    </div>
  );
};

export default MainMaps;

Answer 1

呈现问题似乎与库本身有关。我可以建议的一种替代方法是 use/load Google Maps API 脚本而不是依赖第 3 方库。这样，您可以按照 Google.

提供的 official documentation 进行操作

通过加载脚本，我们现在可以跟随他们Directions API documentation:

这里有一个示例应用供您参考：https://stackblitz.com/edit/react-directions-64165413

App.js


    import React, { Component } from 'react';
    import { render } from 'react-dom';
    import Map from './components/map';
    import "./style.css";
    
    class App extends Component {
     
      render() {
        return (
           <Map 
            id="myMap"
            options={{
              center: { lat: 31.582045, lng: 74.329376 },
              zoom: 8
            }}
          />
        );
      }
    }
    
    export default App;

map.js


    import React, { Component } from "react";
    import { render } from "react-dom";
    
    class Map extends Component {
      constructor(props) {
        super(props);
        this.state = {
          map: "",
          origin: "",
          destination: ""
        };
        this.handleInputChange = this.handleInputChange.bind(this); 
        this.onSubmit = this.onSubmit.bind(this);
      }
    
      onScriptLoad() {
        this.state.map = new window.google.maps.Map(
          document.getElementById(this.props.id),
          this.props.options
        );
      }
    
      componentDidMount() {
        if (!window.google) {
          var s = document.createElement("script");
          s.type = "text/javascript";
          s.src = `https://maps.google.com/maps/api/js?key=YOUR_API_KEY`;
          var x = document.getElementsByTagName("script")[0];
          x.parentNode.insertBefore(s, x);
          // Below is important.
          //We cannot access google.maps until it's finished loading
          s.addEventListener("load", e => {
            this.onScriptLoad();
          });
        } else {
          this.onScriptLoad();
        }
      }
    
      onSubmit(event) {    
        this.calculateAndDisplayRoute();
        event.preventDefault();
      }
    
      calculateAndDisplayRoute() {
        var directionsService = new google.maps.DirectionsService();
        var directionsRenderer = new google.maps.DirectionsRenderer();
        directionsRenderer.setMap(this.state.map);
        directionsService.route(
          {
            origin: { query: this.state.origin },
            destination: { query: this.state.destination },
            travelMode: "DRIVING"
          },
          function(response, status) {
            if (status === "OK") {
              directionsRenderer.setDirections(response);
            } else {
              window.alert("Directions request failed due to " + status);
            }
          }
        );
        
      }
    
      handleInputChange(event) {
        const target = event.target;
        const value = target.type === "checkbox" ? target.checked : target.value;
        const name = target.name;
    
        this.setState({
          [name]: value
        });
      }
      addMarker(latLng) {
        var marker = new window.google.maps.Marker({
          position: { lat: -33.8569, lng: 151.2152 },
          map: this.state.map,
          title: "Hello Sydney!"
        });
        var marker = new google.maps.Marker({
          position: latLng,
          map: this.state.map
        });
      }
    
      render() {
        return (
          <div>
            <input
              id="origin"
              name="origin"
              value={this.state.origin}
              placeholder="Origin"
              onChange={this.handleInputChange}
            />
            <input
              id="destination"
              name="destination"
              value={this.state.destination}
              placeholder="Destination"
              onChange={this.handleInputChange}
            />
            <button id="submit" onClick={this.onSubmit}>
              Search
            </button>
            <div className="map" id={this.props.id} />
          </div>
        );
      }
    }
    
    export default Map;

Answer 2

render 应该始终保持纯净。在渲染过程中做副作用是一个非常糟糕的做法。

您正在 directionCallback 中连续调用 setstate。您只需要添加另一个条件 count.current < 2.

const [origin, setOrigin] = React.useState('chennai');
  const [destination, setDestination] = React.useState('bangalore');
  const [response, setResponse] = React.useState(null);
let count = React.useRef(0);
  const directionsCallback = res => {
    if (res !== null && && count.current < 2) {
      if (res.status === 'OK') {
        count.current += 1;
        setResponse(res);
      } else {
        count.current = 0;
        console.log('res: ', res);
      }
    }
  };

  <DirectionsService
            options={{
              destination: destination,
              origin: origin,
              travelMode: 'DRIVING'
            }}
            callback={directionsCallback}
          />

但是回调的响应没有在 DirectionsRenderer 中呈现。

我也没有收到任何错误消息。

{response !== null && (
            <DirectionsRenderer
              // required
              options={{
                directions: response
              }}
            />
          )}

回调响应为

Answer 3

嘿，我来晚了，但您正在立即调用正在重新渲染和搞乱的回调函数。只需更改以下内容。

callback={direactionsCallback}

有了这个：

callback={(e) => directionsCallback(e)}

Answer 4

有点晚了，但遇到同样问题的人可以参考这个。 DirectionService 将一次又一次地重新呈现，您必须停止它，直到从 DirectionService 回调函数获得 DirectionRender 位置（lat 和 lng）的响应结果。您可以在开头设置一个空变量，并将 DirectionService 的条件应用到运行，直到该变量为空。在 DirectionService 的回调中，将此变量设置为从此回调收到的响应，然后就可以了。我在 DirectionRender class 中遇到了另一个问题，一旦我更新状态，它就会一次又一次地重新渲染。在选项中，将 preserveViewport 设置为 true 以保留视图。

DirectionService问题可以参考这里： https://react-google-maps-api-docs.netlify.app/#directionsrenderer

react-google-maps/api DirectionsService 不断重新呈现自身

react-google-maps/api DirectionsService keeps rerendering itself

google-maps

google-api

google-directions-api

reactjs

react-google-maps