如何飞往react-leaflet中的某个位置

Question

所以我对反应和传单真的很陌生，但我想做的基本上就是让用户输入一些输入，然后在他们按回车键后，触发一个事件，然后该事件飞到从该输入生成的坐标。我正在使用地理编码，经纬度坐标已成功生成。但是我不知道如何使地图飞到那个位置。这是我到目前为止所拥有的：

import './App.css';
import * as React from "react";
import { ChakraProvider } from "@chakra-ui/react";
import { MapContainer, TileLayer, Marker, Popup, useMapEvents } from 'react-leaflet'
import 'leaflet/dist/leaflet.css'
import Geocode from "react-geocode";
import SearchBar from './SearchBar';

class App extends React.Component {
  constructor(props){
    super(props)
    this.state = {
      position: [43.653225, -79.383186]
    }
  }
  mapRef = React.createRef();

  changePos (pos) {
    this.setState({position: pos});
    this.mapRef.current.flyTo(pos);
  }

  render () {
    return (
      <ChakraProvider resetCSS = {false}>
        <div className = "App">
          <div id="title">
            <h1>
              CovidStopSpots
            </h1>
              <p>A responsive tracker for Covid-19.</p>
          <SearchBar changePos = {this.changePos.bind(this)}></SearchBar>
          </div>
          <div id="map">
            <MapContainer center={this.state.position} zoom={13} scrollWheelZoom={false} ref={this.mapRef}>
              <TileLayer
                attribution='&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
                url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
              />
              <Marker position={[43.653225, -79.383186]}>
                <Popup>
                  A pretty CSS3 popup. <br /> Easily customizable.
                </Popup>
              </Marker>
            </MapContainer>
          </div>
      </div>
      </ChakraProvider>
    )
  }
}

export default App;

当前的代码也会生成此错误：

Unhandled Rejection (TypeError): Cannot read property 'flyTo' of null

Answer 1

在react-leaflet版本3中，您可以使用prop获取地图实例whenCreated，然后当您不想将其用于子组件时使用它飞到另一个位置MapContainer's。

this.state = {
      position: [43.653225, -79.383186],
      map: null
 }

删除 ref 并使用whenCreatedprop

<MapContainer center={this.state.position} zoom={13} scrollWheelZoom={false} whenCreated={map => this.setState({ map })}>

然后在你的changePos事件中使用this.state.map来飞行

 changePos (pos) {
    this.setState({position: pos});
    const {map} = this.state;
    if (map) map.flyTo(pos);
 }