在循环中创建标记 - 在单击Listener内部时，Infowindow不会打开 [英] creating markers in loop - Infowindow does not open when inside an click Listener

问题描述

我有一个带有多个标记的谷歌地图，每个都有自己的infowindow。

当我点击时什么也没有发生。 fyi：我知道这个监听器会引发火灾，因为我之前已经提醒过它，它工作正常。

问题代码是：

  google.maps.event.addListener（point [i]，'click'，function（）{
 infowindow [i] = new google.maps.InfoWindow （{content：contentString [i]}）; 
 infowindow [i] .open（map，point [i]）; 
}）; 
  

如果我只做
$ b $

  infowindow [i] = new google.maps.InfoWindow（{content：contentString [i]}）; 
 infowindow [i] .open（map，point [i]）; 
  

有效。但不是在我的addListener函数中。我想这是谷歌地图不喜欢的东西，但萤火虫给我0错误。

真的需要你的帮助。非常感谢！

解决方案

这是因为您可能在循环内关闭了！因此，在回调被调用时，回调中的变量 i 已被覆盖。你有两个选择如何解决它：

$ b <1>经典的循环闭包解决方法（你为每个循环迭代做另一个闭包）：$ b （i = 0; i< 20; i ++）{（function（i）{
google.maps.event.addListener（$ i））的
$ b

 点[i]，'点击'，函数（）{
 infowindow [i] = new google.maps.InfoWindow（{content：contentString [i]}）; 
 infowindow [i] .open地图，点[i]）; 
}）; 
}）（i）; 
} 
  

<2>避免关闭并使用标记数据结构：

$ （i = 0; i <20; i ++）{
point [i] .i = i; b
$ b

  
 google.maps.event.addListener（point [i]，'click'，function（）{
 this.myinfowindow = new google.maps.InfoWindow（{content：contentString [this.i]} ）; 
 this.myinfowindow.open（map，this）; 
}）; 
 
 $ / code> 

（或者您也可以将contentString也移动到标记处： point [i] .contentString = ... 并在点击处理程序中使用 this.contentString ，那么您不需要 point [i] .i 属性。）

我个人更喜欢第二种解决方案，关闭消耗内存等。

i have a google map with multiple markers and each has its own infowindow.

nothing happens when i click. fyi: i know it the listener fires because i did put a alert in ther before and it worked.

Problem Code is:

google.maps.event.addListener(point[i], 'click', function() {
     infowindow[i] = new google.maps.InfoWindow({content: contentString[i] });
     infowindow[i].open(map,point[i]);
});

if i only do

     infowindow[i] = new google.maps.InfoWindow({content: contentString[i] });
     infowindow[i].open(map,point[i]);

it works. but not in my addListener function. i guess ther is something that googlemaps doesnt like but firebug gives me 0 errors..

really need your help. Thanks a lot!

解决方案

It is because you probably have closure within loop! So the variable i in callback is already overwritten at the time when the callback is called. You have two options how to fix it:

1) classical "closure in loop" workaround (you do another closure for every loop iteration):

for (i = 0; i < 20; i++) { (function  (i) {
    google.maps.event.addListener(point[i], 'click', function() {
         infowindow[i] = new google.maps.InfoWindow({content: contentString[i] });
         infowindow[i].open(map,point[i]);
    });
})(i);
}

2) avoid closure and use the marker data structure:

for (i = 0; i < 20; i++) {
    point[i].i = i;
    google.maps.event.addListener(point[i], 'click', function() {
         this.myinfowindow = new google.maps.InfoWindow({content: contentString[this.i] });
         this.myinfowindow.open(map, this);
    });
}

(or you could also move the contentString also to the marker: point[i].contentString = ... and use this.contentString in the click handler. Then you don't need the point[i].i attribute.)

Personally I much more prefer the 2nd solution over the first, since the closures consume memory etc.

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