Question

我正在尝试获取保存在firebase实时数据库中的坐标，并使用google maps API将它们显示在地图上。这是我到目前为止的代码。现在它打开并使用html5地理位置API显示用户当前位置，并使用Geofire将lat和long坐标同步到firebase实时数据库。

我不知道如何检索这些点并在谷歌地图上同时显示不同用户位置的多个点。如果有人能帮助我，我会非常感激。

＆＃13;

<script src="https://cdn.firebase.com/libs/geofire/4.1.2/geofire.min.js"></script>
<script src="https://www.gstatic.com/firebasejs/4.12.1/firebase.js"></script>
<!DOCTYPE html>
<html>
  <head>
    <title>Geolocation</title>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <style>
      /* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
      #map {
        height: 100%;
      }
      /* Optional: Makes the sample page fill the window. */
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
    </style>
    <!-- Place this inside the HTML head; don't use async defer for now -->
<script src="https://www.gstatic.com/firebasejs/4.12.1/firebase.js"></script>
<script src="https://cdn.firebase.com/libs/geofire/4.1.2/geofire.min.js"></script>

  <script>
        
        var config = {
    apiKey: "AIzaSyCWZjRe2CK8Hu2VN35AgZOQ7lQZKcI-UWM",
    authDomain: "carrier-35d7c.firebaseapp.com",
    databaseURL: "https://carrier-35d7c.firebaseio.com",
    projectId: "carrier-35d7c",
    storageBucket: "carrier-35d7c.appspot.com",
    messagingSenderId: "827792028763"
  };

        if (!firebase.apps.length) {
            firebase.initializeApp(config);
        }
        
        //Create a node at firebase location to add locations as child keys
        var locationsRef = firebase.database().ref("locations");
        
        // Create a new GeoFire key under users Firebase location
        var geoFire = new GeoFire(locationsRef.push());
      </script>


  </head>
  <body>
    <div id="map"></div>
    <script>
      // Note: This example requires that you consent to location sharing when
      // prompted by your browser. If you see the error "The Geolocation service
      // failed.", it means you probably did not give permission for the browser to
      // locate you.

      var map, infoWindow;
      var lat, lng;
      function initMap() {
        map = new google.maps.Map(document.getElementById('map'), {
          center: {lat: -34.397, lng: 150.644},
          zoom: 18
        });
        infoWindow = new google.maps.InfoWindow;

        // Try HTML5 geolocation.
        if (navigator.geolocation) {
          navigator.geolocation.getCurrentPosition(function(position) {
            lat = position.coords.latitude;
            lng = position.coords.longitude;

            var pos = {lat: lat, lng: lng };
                _setGeoFire();
          

            infoWindow.setPosition(pos);
            infoWindow.setContent('Location found.');
            infoWindow.open(map);
            map.setCenter(pos);
          }, function() {
            handleLocationError(true, infoWindow, map.getCenter());
          });
        } else {
          // Browser doesn't support Geolocation
          handleLocationError(false, infoWindow, map.getCenter());
        }
      }

      function handleLocationError(browserHasGeolocation, infoWindow, pos) {
        infoWindow.setPosition(pos);
        infoWindow.setContent(browserHasGeolocation ?
                              'Error: The Geolocation service failed.' :
                              'Error: Your browser doesn\'t support geolocation.');
        infoWindow.open(map);
      }

      function _setGeoFire(){
    geoFire.set("User", [lat, lng]).then(()=>{
            console.log("Location added");
        }).catch(function(error) {
            console.log(error);
        });


}
    </script>
    <script 
    src="https://maps.googleapis.com/maps/api/js?key=AIzaSyD2nPlSt_nM7PSKD8So8anbUbBYICFWcCA&callback=initMap">
    </script>
  </body>
</html>

＆＃13;

Answer 1

相关问题：

How to retrieve data from Firebase using Javascript?

我只从该数据库中获得一个结果：

c20ej76jhb
45.546058，-122.813203

使用此代码（使用on而不是once）引用我使用多个位置（以及不同格式的数据）创建的数据库：

var locationsRef = firebase.database().ref("locations");
locationsRef.on('child_added', function(snapshot) {
var data = snapshot.val();
var marker = new google.maps.Marker({
  position: {
    lat: data.lat,
    lng: data.lng
  },
  map: map
});
bounds.extend(marker.getPosition());
marker.addListener('click', (function(data) {
  return function(e) {
    infowindow.setContent(data.name + "<br>" + this.getPosition().toUrlValue(6) + "<br>" + data.message);
    infowindow.open(map, this);
  }
}(data)));
map.fitBounds(bounds);

}）;

proof of concept fiddle

来自您的数据库：

来自我的（有多个位置和上面的修改过的代码）：

代码段：

function initialize() {
  var infowindow = new google.maps.InfoWindow();
  var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, -122.1419),
      zoom: 13,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  // Initialize Firebase
  var config = {
    apiKey: "AIzaSyC8HcClvIT_FlG8ZwCji4LG-qNx8D9VCrs",
    authDomain: "geocodeziptest.firebaseapp.com",
    databaseURL: "https://geocodeziptest.firebaseio.com",
    projectId: "geocodeziptest",
    storageBucket: "geocodeziptest.appspot.com",
    messagingSenderId: "1096545848604"
  };
  firebase.initializeApp(config);
  //Create a node at firebase location to add locations as child keys
  var locationsRef = firebase.database().ref("locations");
  var bounds = new google.maps.LatLngBounds();
  locationsRef.on('child_added', function(snapshot) {
    var data = snapshot.val();
    console.log(data);
    var marker = new google.maps.Marker({
      position: {
        lat: data.lat,
        lng: data.lng
      },
      map: map
    });
    bounds.extend(marker.getPosition());
    marker.addListener('click', (function(data) {
      return function(e) {
        infowindow.setContent(data.name + "<br>" + this.getPosition().toUrlValue(6) + "<br>" + data.message);
        infowindow.open(map, this);
      }
    }(data)));
    map.fitBounds(bounds);
  });
}
google.maps.event.addDomListener(window, "load", initialize);

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js"></script>
<script src="https://www.gstatic.com/firebasejs/4.12.1/firebase.js"></script>
<script src="https://cdn.firebase.com/libs/geofire/4.1.2/geofire.min.js"></script>
<div id="map_canvas"></div>

如何在Google地图上显示存储在Firebase数据库中的多个标记坐标

1 个答案: