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。
答案 0 :(得分：0)
解决：
-firebase sdk版本到最新，
- 改变一些代码
（auth匿名，firebase.child - ＆gt; firebase.database（）。ref ...）