Question

我是一名学习网络火力基础的学生，有一点我无法理解的问题。

以下是google web Developer页面上的代码 https://developers.google.com/maps/documentation/javascript/firebase

<!DOCTYPE html>
<html>
  <head>
    <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>
  </head>
  <body>
    <div id="map"></div>

    <script src="https://cdn.firebase.com/js/client/2.3.2/firebase.js"></script>
    <script>
      /**
      * Reference to Firebase database.
      * @const
      */
      var firebase = new Firebase('https://fire-map-tutorial.firebaseio.com/');

      /**
      * Data object to be written to Firebase.
      */
      var data = {
        sender: null,
        timestamp: null,
        lat: null,
        lng: null
      };

      function makeInfoBox(controlDiv, map) {
        // Set CSS for the control border.
        var controlUI = document.createElement('div');
        controlUI.style.boxShadow = 'rgba(0, 0, 0, 0.298039) 0px 1px 4px -1px';
        controlUI.style.backgroundColor = '#fff';
        controlUI.style.border = '2px solid #fff';
        controlUI.style.borderRadius = '2px';
        controlUI.style.marginBottom = '22px';
        controlUI.style.marginTop = '10px';
        controlUI.style.textAlign = 'center';
        controlDiv.appendChild(controlUI);

        // Set CSS for the control interior.
        var controlText = document.createElement('div');
        controlText.style.color = 'rgb(25,25,25)';
        controlText.style.fontFamily = 'Roboto,Arial,sans-serif';
        controlText.style.fontSize = '100%';
        controlText.style.padding = '6px';
        controlText.textContent = 'The map shows all clicks made in the last 10 minutes.';
        controlUI.appendChild(controlText);
      }

      /**
      * Starting point for running the program. Authenticates the user.
      * @param {function()} onAuthSuccess - Called when authentication succeeds.
      */
      function initAuthentication(onAuthSuccess) {
        firebase.authAnonymously(function(error, authData) {
          if (error) {
            console.log('Login Failed!', error);
          } else {
            data.sender = authData.uid;
            onAuthSuccess();
          }
        }, {remember: 'sessionOnly'});  // Users will get a new id for every session.
      }

      /**
       * Creates a map object with a click listener and a heatmap.
       */
      function initMap() {
        var map = new google.maps.Map(document.getElementById('map'), {
          center: {lat: 0, lng: 0},
          zoom: 3,
          styles: [{
            featureType: 'poi',
            stylers: [{ visibility: 'off' }]  // Turn off POI.
          },
          {
            featureType: 'transit.station',
            stylers: [{ visibility: 'off' }]  // Turn off bus, train stations etc.
          }],
          disableDoubleClickZoom: true,
          streetViewControl: false,
        });

        // Create the DIV to hold the control and call the makeInfoBox() constructor
        // passing in this DIV.
        var infoBoxDiv = document.createElement('div');
        makeInfoBox(infoBoxDiv, map);
        map.controls[google.maps.ControlPosition.TOP_CENTER].push(infoBoxDiv);

        // Listen for clicks and add the location of the click to firebase.
        map.addListener('click', function(e) {
          data.lat = e.latLng.lat();
          data.lng = e.latLng.lng();
          addToFirebase(data);
        });

        // Create a heatmap.
        var heatmap = new google.maps.visualization.HeatmapLayer({
          data: [],
          map: map,
          radius: 16
        });

        initAuthentication(initFirebase.bind(undefined, heatmap));
      }

      /**
       * Set up a Firebase with deletion on clicks older than expirySeconds
       * @param {!google.maps.visualization.HeatmapLayer} heatmap The heatmap to
       * which points are added from Firebase.
       */
      function initFirebase(heatmap) {

        // 10 minutes before current time.
        var startTime = new Date().getTime() - (60 * 10 * 1000);

        // Reference to the clicks in Firebase.
        var clicks = firebase.child('clicks');

        // Listener for when a click is added.
        clicks.orderByChild('timestamp').startAt(startTime).on('child_added',
          function(snapshot) {

            // Get that click from firebase.
            var newPosition = snapshot.val();
            var point = new google.maps.LatLng(newPosition.lat, newPosition.lng);
            var elapsed = new Date().getTime() - newPosition.timestamp;

            // Add the point to  the heatmap.
            heatmap.getData().push(point);

            // Requests entries older than expiry time (10 minutes).
            var expirySeconds = Math.max(60 * 10 * 1000 - elapsed, 0);
            // Set client timeout to remove the point after a certain time.
            window.setTimeout(function() {
              // Delete the old point from the database.
              snapshot.ref().remove();
            }, expirySeconds);
          }
        );

        // Remove old data from the heatmap when a point is removed from firebase.
        clicks.on('child_removed', function(snapshot, prevChildKey) {
          var heatmapData = heatmap.getData();
          var i = 0;
          while (snapshot.val().lat != heatmapData.getAt(i).lat()
            || snapshot.val().lng != heatmapData.getAt(i).lng()) {
            i++;
          }
          heatmapData.removeAt(i);
        });
      }

      /**
       * Updates the last_message/ path with the current timestamp.
       * @param {function(Date)} addClick After the last message timestamp has been updated,
       *     this function is called with the current timestamp to add the
       *     click to the firebase.
       */
      function getTimestamp(addClick) {
        // Reference to location for saving the last click time.
        var ref = firebase.child('last_message/' + data.sender);

        ref.onDisconnect().remove();  // Delete reference from firebase on disconnect.

        // Set value to timestamp.
        ref.set(Firebase.ServerValue.TIMESTAMP, function(err) {
          if (err) {  // Write to last message was unsuccessful.
            console.log(err);
          } else {  // Write to last message was successful.
            ref.once('value', function(snap) {
              addClick(snap.val());  // Add click with same timestamp.
            }, function(err) {
              console.warn(err);
            });
          }
        });
      }

      /**
       * Adds a click to firebase.
       * @param {Object} data The data to be added to firebase.
       *     It contains the lat, lng, sender and timestamp.
       */
      function addToFirebase(data) {
        getTimestamp(function(timestamp) {
          // Add the new timestamp to the record data.
          data.timestamp = timestamp;
          var ref = firebase.child('clicks').push(data, function(err) {
            if (err) {  // Data was not written to firebase.
              console.warn(err);
            }
          });
        });
      }
    </script>
    <script async defer
        src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=visualization&callback=initMap">
    </script>
  </body>
</html>

我只需更改下面的两个代码，

1＆GT;＆GT;我的firebase数据库网址

var firebase = new Firebase（'https://myfirebase-123cc.firebaseio.com/'）;

2 - ;＆GT;我的api密钥

<script async defer
    src="https://maps.googleapis.com/maps/api/js?key=MY_API_KEY&libraries=visualization&callback=initMap">
</script>

但是虽然我锁定了数据库但它没有用（向所有人开放，任何人都可以阅读，可以写）

{
  "rules": {
    ".read": true,
    ".write": true
  }
}

当我点击时，数据显示在我的数据库-firebase上，但不在热图上。

问题是））我可以在firebase-database中找到数据但它没有显示在热图上。

代码与google中的示例代码相同。唯一的区别是数据库的URL。

Answer 1

解决：

-firebase sdk版本到最新，
- 改变一些代码
（auth匿名，firebase.child - ＆gt; firebase.database（）。ref ...）

使用Firebase热图进行协作实时映射

1 个答案: