我不明白为什么setTimeout无法正常工作。

我想将每个标记放到不同的时间,而不是同时放下。

将此代码粘贴并运行到http://jsfiddle.net中,然后删除注释以查看有趣的行为:

        //setTimeout(function() {
            addMarker(m);
        //}, i * 500);




<link href="http://code.google.com/apis/maps/documentation/javascript/examples/default.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="//maps.googleapis.com/maps/api/js?sensor=false"></script>
<script type="text/javascript">
  var berlin = new google.maps.LatLng(52.520816, 13.410186);
  var neighborhoods = [
    new google.maps.LatLng(52.511467, 13.447179),
    new google.maps.LatLng(52.549061, 13.422975),
    new google.maps.LatLng(52.497622, 13.396110),
    new google.maps.LatLng(52.517683, 13.394393)
  ];
  var map;
  function initialize() {
    var mapOptions = {
      zoom: 12,
      mapTypeId: google.maps.MapTypeId.ROADMAP,
      center: berlin
    };
    map = new google.maps.Map(document.getElementById("map_canvas"),mapOptions);
  }

  function drop() {
    var j = 0;
    for (var i = 0; i < neighborhoods.length; i++) {
        var m = neighborhoods[i];
        //setTimeout(function() {
            addMarker(m);
        //}, i * 500);
    }
  }
  function addMarker(m) {
    new google.maps.Marker({
      position: m,
      map: map,
      draggable: false,
      animation: google.maps.Animation.DROP
    });
  }
</script>
<body onload="initialize()">
<div id="map_canvas" style="width: 500px; height: 400px;">map div</div>
<button id="drop" onclick="drop()">Drop Markers</button>
</body>

最佳答案

这是因为'm'的值在timeOut事件触发之前很久就已更改。

您应该将此代码包装在闭包中,以捕获m的值。

就像是:

for (var i = 0; i < neighborhoods.length; i++) {
    var m = neighborhoods[i];

    (function(n){
      setTimeout(function() {
        addMarker(n);
     }, i * 500);
   }(m));
}

关于javascript - setTimeout()并在Google map 上放置标记,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/9294740/

10-12 12:35
查看更多