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javascript - google getLocation 函数在我的脚本中不起作用

转载 作者:行者123 更新时间:2023-12-02 16:50:03 25 4
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大家好,我需要在我的网站上显示一个谷歌地图,其中包含我的家标记(我使用商店位置)并以用户位置为中心。我尝试:

<script>
var myCenter = new google.maps.LatLng('xxx');
var userCenter;

function getLocation() {
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(showPosition);
}
}

function showPosition(position) {
var latlon = position.coords.latitude + "," + position.coords.longitude;
userCenter=new google.maps.LatLng(latlon);
}

var marker;

function initialize()
{
var mapProp = {
center: userCenter,
zoom:15,
mapTypeId:google.maps.MapTypeId.ROADMAP
};

var map=new google.maps.Map(document.getElementById("googleMap"),mapProp);

marker=new google.maps.Marker({
position:myCenter,
});

marker.setMap(map);

var infowindow = new google.maps.InfoWindow({
content:"Casa"
});

google.maps.event.addListener(marker, 'click', function() {
infowindow.open(map,marker);
});
}

google.maps.event.addDomListener(window, 'load', initialize);

</script>

如果我不使用 userCenter 并使用 MyCenter,则 map 将正常工作并以 MyCenter 为中心显示。

最佳答案

问题在于函数的执行顺序。您希望在 userCenter 可用之前使用 userCenter。这会产生一个错误(在 var mapProp = {center: userCenter, ...} 上),因此初始化停止工作。

顺便说一下,你永远不会调用 getLocation()。仅定义的函数不执行任何操作。仅当您在某处调用函数时,函数才会执行某些操作。

(顺便说一句2:navigator.geolocation不是Google服务。它是网络浏览器提供的服务)

我在代码中添加了额外的注释

<script src="http://maps.googleapis.com/maps/api/js?sensor=true"></script>
<script>
var myCenter = new google.maps.LatLng(50.845463, 4.357112);
var userCenter;
var marker;
var map;

// sends a request to get the location of the user.
// Notice: you will have to wait for the callback (= showPosition) before you have the result of this request.
// So you cannot rely only on userCenter. You must use myCenter, until you are sure that showPosition receives the response
function getUserLocation() {
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(showPosition);
}
}

// Response of getUserLocation(). The location of the client is known.
// Notice: by this time initialize() has been called. initialize() doesn't know anything about userCenter.
// userCenter will only get a value when this function is called.
function showPosition(position) {
userCenter = new google.maps.LatLng(
position.coords.latitude,
position.coords.longitude
);
// Now we know the position of the client. We can set the center of the map to this location
map.setCenter(userCenter);
}

// this function initializes Google maps. It is triggered the moment the DOM of the web page is loaded.
function initialize() {
// let's start the request to get the position of the user
getUserLocation();

var mapProp = {
center: myCenter, // notice: userCenter is still undefined, you cannot use it yet.
zoom:15,
mapTypeId:google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById("googleMap"), mapProp);
marker = new google.maps.Marker({
position: myCenter,
map: map // this replaces marker.setMap(map);
});

var infowindow = new google.maps.InfoWindow({
content: "Casa"
});
// a click on the marker opens the infoWindow
google.maps.event.addListener(marker, 'click', function() {
infowindow.open(map, marker);
});
}
google.maps.event.addDomListener(window, 'load', initialize);
</script>

关于javascript - google getLocation 函数在我的脚本中不起作用,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26754939/

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