【问题标题】:React Leaflet: Dynamic Markers, cannot read property 'addLayer'React Leaflet:动态标记,无法读取属性“addLayer”
【发布时间】:2020-09-29 18:12:03
【问题描述】:

我一直在开发一个地图组件,该组件呈现从搜索中流入的结果点。我已经完成了大部分工作,直到我开始为 return 语句传递道具。我使用的是我自己的组件,而不是 react-leaflet 的。我注意到如果我使用<Map ... /> 并使用props.locations.map( ... 渲染它工作正常。如果我用<map ref={map} > 引用我的map = L.map(...) 并尝试用道具渲染<Marker .../> ,它会在尝试创建图层并将其添加到地图时立即中断。

组件的JS文件如下:

    import React, {Component, useEffect, useState} from "react";
    import {Map, Marker, Popup, TileLayer} from "react-leaflet";
    import * as L from 'leaflet'
    import 'leaflet-draw'
    import 'leaflet/dist/leaflet.css';
    import 'leaflet-easybutton'
    import 'leaflet-easybutton/src/easy-button.css';
    import Style from './MapSearch.css'
    import icon from 'leaflet/dist/images/marker-icon.png';
    import iconShadow from 'leaflet/dist/images/marker-shadow.png';



    const MapSearch = (props) => {


        const [layers,setLayers] = useState([]);
        const [results,setResults] = useState([]); //Not used
        const [map,setMap]=useState({});


    


    useEffect(()=> {

        console.log('mounted');
        let map = L.map('mapsearch').setView([51.505, -0.09], 6);

        L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
            attribution: '&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors',
        }).addTo(map);

        /** Add the feature group and draw control to the map. */
        let drawnItems = new L.FeatureGroup();
        map.addLayer(drawnItems);
        const drawControl = new L.Control.Draw({
            position: 'topright',
            draw: {
                polyline: false,
                rectangle: false,
                circlemarker: false,
                polygon: false,
                circle: true,
                marker: true,
            },
            edit: {
                featureGroup: drawnItems,
                remove: true,
            },
        });
        map.addControl(drawControl);


        /** On shape drawn, add the new layer to the map. */
        map.on(L.Draw.Event.CREATED, (e) => {
            const type = e.layerType;
            const layer = e.layer;
            if (type === 'marker') {
                layer.bindPopup('popup');
            }
            console.log('LAYER ADDED:', layer);
            drawnItems.addLayer(layer);

           // this.setState({layers: drawnItems.getLayers()});
            let testArr=drawnItems.getLayers();                         /**BROKEN SECTIoN TODO */
           // setLayers(layers=> [...layers,layer]);
            //console.log({layers});

            console.log('GEO JSON', drawnItems.toGeoJSON());
            console.log(' LAYERS', drawnItems.getLayers());


        });

        L.easyButton('fa-search', () => {
            isWithinPolygon(props); //Removed because not relevant to question 

        }, 'Search Current Results within drawn layers', {position: 'topright'}).addTo(map);


        map.on(L.Draw.Event.EDITED, (e) => {
            const layers = e.layers;
            let countOfEditedLayers = 0;
            console.log('LAYER EDITED:', layers);
            layers.eachLayer((layer) => {
                countOfEditedLayers++;
            });
        });

        setMap(map); //hook to set map
        //this.setState({map: map});

         console.log("map:",{map}); }
        ,[]);



    return (

        <div id='mapsearch'>
            <map center={[0, 0]} zoom={0}>

                {props.locations.map(marker => (
                    (marker.props.isLocationEnabled === true ?
                            (marker.props.isMarkerClicked === true ?
                                    (<Marker
                                        key={marker.props.id}
                                        position={ [
                                            marker.props.lat,
                                            marker.props.long
                                        ]}
                                        opacity= '1.0'>
                                        <Popup>
                                            <b>Media ID:</b> {marker.props.values.mediaId}
                                            <br/>
                                            <b>Created Date:</b> {marker.props.values.createdDate}
                                            <br/>
                                            <b>Media URL:</b> <button onClick={()=> window.open(marker.props.values.mediaURL)}>Link</button>
                                        </Popup>
                                    </Marker>) :
                                    (<Marker
                                        key={marker.props.id}
                                        position={ [
                                            marker.props.lat,
                                            marker.props.long
                                        ]}
                                        opacity= '0.5'>
                                        <Popup>
                                            <b>Media ID:</b> {marker.props.values.mediaId}
                                            <br/>
                                            <b>Created Date:</b> {marker.props.values.createdDate}
                                            <br/>
                                            <b>Media URL:</b> <button onClick={()=> window.open(marker.props.values.mediaURL)}>Link</button>
                                        </Popup>
                                    </Marker>)
                            ) : (<div></div>)
                    )
                ))}
            </map>
        </div>
    );
};

export default MapSearch;

索引:

<head>
<meta charset="utf-8" />
<link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta name="theme-color" content="#000000" />
<meta
  name="description"
  content="Media Search UI"
/>
<link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
<!--
  manifest.json provides metadata used when your web app is installed on a
  user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
-->
<link rel="manifest" href="%PUBLIC_URL%/manifest.json" />

<link rel="stylesheet" href="https://unpkg.com/leaflet@1.7.1/dist/leaflet.css"
      integrity="sha512-xodZBNTC5n17Xt2atTPuE1HxjVMSvLVW9ocqUKLsCC5CXdbqCmblAshOMAS6/keqq/sMZMZ19scR4PsZChSR7A=="
      crossorigin=""/>
<script src="https://unpkg.com/leaflet@1.7.1/dist/leaflet.js"
        integrity="sha512-XQoYMqMTK8LvdxXYG3nZ448hOEQiglfqkJs1NOQV44cWnUrBc8PkAOcXy20w0vlaXaVUearIOBhiXZ5V3ynxwA=="
        crossorigin=""></script>

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet.draw/1.0.4/leaflet.draw.css"/>


<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet.draw/1.0.4/leaflet.draw.js"></script>
<script src="https://cdn.jsdelivr.net/npm/leaflet-easybutton@2/src/easy-button.js"></script>
<link href="http://netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.css" rel="stylesheet">
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet">

<!--
  Notice the use of %PUBLIC_URL% in the tags above.
  It will be replaced with the URL of the `public` folder during the build.
  Only files inside the `public` folder can be referenced from the HTML.

  Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
  work correctly both with client-side routing and a non-root public URL.
  Learn how to configure a non-root public URL by running `npm run build`.
-->
<title>React App</title>

对此我感到很困惑。为什么使用&lt;Map&gt;时可以映射和渲染&lt;Markers&gt;而不是我的&lt;map /&gt;

编辑: 使用 &lt;Map ref={map} ... /&gt; 的屏幕截图。添加重复图层,使 80% 的地图不可拖动。

【问题讨论】:

  • 你需要使用 react-leaflet 的 Map 组件或者使用 vanilla 传单来初始化地图。使用本机传单代码初始化地图并使用 react-leaflet 的抽象组件然后是没有意义的。使用react-leaflet 的地图组件和mapRef
  • 并没有解决它,而是让我回到了我遇到的旧问题。它似乎覆盖了地图。我可以看到两个缩放面板相互重叠,因此它使大部分地图无法拖动。在事先解决这个问题时,似乎 ref 属性不起作用。我可以看到我的传单绘制代码,所以它必须在某种程度上识别它。我将在帖子@kboul 中添加屏幕截图
  • 也许它与我的第一个 div,
    如果我删除它,我得到错误:找不到地图容器。
  • 你能做一个演示来重现这个问题吗?
  • 无法做到这一点,我尝试过,但丝毫不知道我在 codepen 中做什么。如果还不是很明显,那么我对这一切都是新手。上面提供的代码将通过将 更改为 呈现自己的 div 时不需要这样做)。我应该包括我不能做 const map = this.leafletMap.leafletElement;然后将其引用为 ref={m => { this.leafletMap = m; }} 它只是不知道 this.leafletMap 是什么

标签: javascript html reactjs leaflet react-leaflet


【解决方案1】:

因此,正如我在 cmets 中提到的,您应该使用 react'leaflet 的 Map 并使用 ref 添加您希望使用本机传单代码的任何插件。

...other imports

const mapRef = useRef();
 
<Map center={position} zoom={13} style={{ height: "100vh" }} ref={mapRef}>
          <TileLayer
            url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
            attribution='&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
          />
         ... your code should go here regarging markers
</Map>

然后在组件挂载时使用 useEffect 获取地图引用并相应地使用它来初始化任何其他传单插件:

useEffect(() => {
    console.log("mounted");

    if (mapRef && mapRef.current) {
      const map = mapRef.current.leafletElement;

      /** Add the feature group and draw control to the map. */
      let drawnItems = new L.FeatureGroup();
      map.addLayer(drawnItems);
      const drawControl = new L.Control.Draw({
        position: "topright",
        draw: {
          polyline: false,
          rectangle: false,
          circlemarker: false,
          polygon: false,
          circle: true,
          marker: true
        },
        edit: {
          featureGroup: drawnItems,
          remove: true
        }
      });
      map.addControl(drawControl);

   ...

   setMap(map); //hook to set map
      //this.setState({map: map});

      console.log("map:", { map });
    }
  }, []);

Demo

【讨论】:

    猜你喜欢
    相关资源
    最近更新 更多
    热门标签