Google Maps API(v3)添加/更新标记

Question

编辑:它现在可以工作,但如果用户不允许或没有基于位置的服务,则不会加载.请参阅jsfiddle示例的已接受答案评论.

我已经查看了一些教程和问题,但我无法安静地了解发生了什么(或者在这种情况下,没有发生).当用户点击链接时,我正在加载我的地​​图.这会加载地图,其中包含用户在中心的当前位置以及用户位置的标记.但是,外面的任何标记if (navigation.location)似乎都没有加载.以下是我目前的代码:

function initialize() {
        // Check if user support geo-location
        if (navigator.geolocation) {
            navigator.geolocation.getCurrentPosition(function(position) {
                var point = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
                var userLat = position.coords.latitude;
                var userLong = position.coords.longitude;
                var mapOptions = {
                    zoom: 8,
                    center: point,
                    mapTypeId: google.maps.MapTypeId.HYBRID
                }

            // Initialize the Google Maps API v3
            var map = new google.maps.Map(document.getElementById("map"), mapOptions);

            // Place a marker
            new google.maps.Marker({
                position: point,
                map: map,
                title: 'Your GPS Location'
            });
        });
    } else {
        var userLat = 53;
        var userLong = 0;
        var mapOptions = {
            zoom: 8,
            center: new google.maps.LatLng(userLat, userLong),
            mapTypeId: google.maps.MapTypeId.HYBRID
        }
        // Place a marker
        new google.maps.Marker({
            position: point,
            map: map,
            title: 'Default Location'
        });
        // Initialize the Google Maps API v3
        var map = new google.maps.Map(document.getElementById("map"), mapOptions);
    }
    <?
    for ($i = 0; $i < sizeof($userLocations); $i++) {
        ?>
        var userLatLong = new google.maps.LatLng(<? echo $userLocations[$i]['lat']; ?>, <? echo $userLocations[$i]['long']; ?>);
        new google.maps.Marker({
            position: userLatLong,
            map: map,
            title:"<? echo $userLocations[$i]['displayName'] . ', ' . $userLocations[$i]['usertype']; ?>"
        });
        <?
    }
    ?>
}

function loadMapScript() {
    if (typeof(loaded) == "undefined") {
        $("#showMap").css("display", "none");
        $("#showMapLink").removeAttr("href");
        $("#map").css("height", "600px");
        $("#map").css("width", "600px");
        var script = document.createElement("script");
        script.type = "text/javascript";
        script.src = "http://maps.googleapis.com/maps/api/js?key=MY_API_KEY&sensor=true&callback=initialize";
        document.body.appendChild(script);
        loaded = true;
    } else {
        alert("Map already loaded!");
    }
}

当用户单击链接时,将调用loadMapScript().php for循环遍历预先创建的包含所有信息的数组.
我猜我不完全理解它,就像我放的时候:

var userLatLong = new google.maps.LatLng(53, 0);
            new google.maps.Marker({
                position: userLatLong,
                map: map,
                title:"Title"
            });

进入控制台(谷歌浏览器),我收到错误:

Error: Invalid value for property <map>: [object HTMLDivElement]

但是,我没有收到任何错误.任何帮助将非常感激!:)

Answer 1

navigator.geolocation.getCurrentPosition() 是异步的.

像这样重新组织您的代码:

var mapOptions = {
    zoom: 8,
    mapTypeId: google.maps.MapTypeId.HYBRID
}

function initialize() {
    // Check if user support geo-location
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(function(position) {
            makeMap(position.coords.latitude, position.coords.longitude, 'Your GPS Location');
        });
    } else {
        makeMap(53, 0, 'DefaultLocation');
    }
}

function makeMap(lat, lng, text) {
    var point = new google.maps.LatLng(lat, lng);
    mapOptions.center = point;
    map = new google.maps.Map(document.getElementById("map"), mapOptions);
    new google.maps.Marker({
        position: point,
        map: map,
        title: text
    });
    <?php for ($i = 0; $i < sizeof($userLocations); $i++): ?>
    var userLatLong = new google.maps.LatLng(<? echo $userLocations[$i]['lat']; ?>, <? echo $userLocations[$i]['long']; ?>);
    new google.maps.Marker({
        position: userLatLong,
        map: map,
        title:"<? echo $userLocations[$i]['displayName'] . ', ' . $userLocations[$i]['usertype']; ?>"
    });
    <?php endforeach ?>
}

另外,考虑将$ userLocations引导到JavaScript变量中,如下所示:

var userLocations = <?php print json_encode($userLocations) ?>;

然后在JavaScript中执行for循环,而不是混合语言.