问题描述
我需要将 react-leaflet 地图定位到用户的当前位置并获取此地图的边框。我尝试应用以下代码,但遇到错误:
TypeError: 无法读取未定义的属性 'locate'(匿名 函数)
请帮帮我!
import React,{ useState,useEffect,useRef } from 'react';
import restaurantsInfo from "./RestaurantsList.json";
import "./App.css";
import { MapContainer,Marker,Popup,TileLayer,useMapEvents } from "react-leaflet";
import { Icon,latLng } from "leaflet";
import Restaurants from "./Restaurants.js";
import LocationMarker from "./LocationMarker.js";
import L from 'leaflet';
const myLocation = [49.1951,16.6068];
const defaultZoom = 13;
export default function App() {
const mapRef = useRef();
useEffect(() => {
const { current = {} } = mapRef;
const { leafletElement: map } = current;
map.locate({
setView: true,});
map.on('locationfound',handleOnLocationFound);
},[]);
function handleOnLocationFound(event) {
const { current = {} } = mapRef;
const { leafletElement: map } = current;
const latlng = event.latlng;
const radius = event.accuracy;
const circle = L.circle(latlng,radius);
circle.addTo(map);
}
return (
<div class="container">
<div style={{height: '400px',width: '500px'}} class="map">
<MapContainer ref={mapRef} center={myLocation} zoom={defaultZoom} scrollWheelZoom={false}>
<TileLayer
attribution='© <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
/>
< /MapContainer >
解决方法
您需要一个自定义组件来完成这项工作并且是 MapContainer
的子组件。从 locationfound
event.bounds
function LocationMarker() {
const [position,setPosition] = useState(null);
const [bbox,setBbox] = useState([]);
const map = useMap();
useEffect(() => {
map.locate().on("locationfound",function (e) {
setPosition(e.latlng);
map.flyTo(e.latlng,map.getZoom());
const radius = e.accuracy;
const circle = L.circle(e.latlng,radius);
circle.addTo(map);
setBbox(e.bounds.toBBoxString().split(","));
});
},[map]);
return position === null ? null : (
<Marker position={position} icon={icon}>
<Popup>
You are here. <br />
Map bbox: <br />
<b>Southwest lng</b>: {bbox[0]} <br />
<b>Southwest lat</b>: {bbox[1]} <br />
<b>Northeast lng</b>: {bbox[2]} <br />
<b>Northeast lat</b>: {bbox[3]}
</Popup>
</Marker>
);
}
在这里使用
<MapContainer
center={[49.1951,16.6068]}
...
<LocationMarker />
</MapContainer>