我無法弄清楚如何在 Leaflet 地圖上調用 fitBounds()?；旧?，我試圖在地圖上顯示多個標記并相應地調整視圖（放大、縮小、飛到等）。我還看到了一些例子，當使用 Leaflet-react 時如何調用 fitBounds()？我試圖實施，但沒有奏效。這是我嘗試過的代碼。import React, { createRef, Component } from "react";import {  Map,  TileLayer,  Marker,  Popup} from "react-leaflet";import L from "leaflet";import Header from "../Layout/Header";import Card from "@material-ui/core/Card";import CardContent from "@material-ui/core/CardContent";import Typography from "@material-ui/core/Typography";import "leaflet/dist/leaflet.css";export class Mapp extends Component {  constructor(props) {    super(props);    this.state = {      map: [],      open: false,      bounds: null,      center: [35.000074, 104.999927]    };    this.mapRef = createRef();    this.groupRef = createRef();  }  toggleHiddden1() {    this.setState({      open: false    });  async componentDidMount() {    try {      await fetch(`https://coronaviva.herokuapp.com/api/1/infected/data/`, {        method: "GET",        headers: {          Accept: "application/json",          "Content-Type": "application/json",          Authorization: "Bearer F9bQK456iUpJVZJLTZsMEKhhENqnGJ"        }      })        .then(map => map.json())        .then(map => {          this.setState({            map          });        });    } catch (err) {      console.log(err);    }    let mapInst = this.refs.map.leafletElement.fitBounds;    console.log(mapInst);  // i tried this but this not working.  }  // centerUpdated(center) {  //   this.center = center;  // }  // boundsUpdated(bounds) {  //   this.bounds = bounds;  // }  render() {    const { map } = this.state;    const pointerIcon = new L.Icon({      iconUrl:        "https://icons.iconarchive.com/icons/paomedia/small-n-flat/512/map-marker-icon.png",      iconAnchor: [25, 40],      iconSize: [50, 50]    });    return (      <div>        <Header          state={this.state}          load={this.onChange}          submit={this.handleSubmit}        />