循环中的对象创建中断；展开的作品 [英] Object creation in loop broken; unrolled works

问题描述

我正在做一些测试并遇到了这种奇怪的情况:第一种情况(在循环中分配 InfoWindows 之类的对象)没有按预期工作，而逐个编写分配工作.

I'm doing some testing and ran into this bizarre situation: The first case (assigning objects like InfoWindows in a loop) does not work as expected, while writing the assignments one by one does work.

预期行为是当鼠标悬停在标记上时打开 InfoWindow.许多窗户应该同时保持打开状态.

The expected behavior is for an InfoWindow to open when the mouse is over a marker. Many windows should stay open at the same time.

从表面上看，我看不出任何区别.这是怎么回事?我展示了每个案例的相关代码和完整的 JSFiddle.

Superficially, I don't see any difference. What's going on? I'm showing relevant code and a full JSFiddle for each case.

不起作用 JSFiddle

    iwArray = [];
    for (var i = 0; i < 3; i++) {
      iwArray[i] = new google.maps.InfoWindow({content: "w "});
      google.maps.event.addListener(marker[i], 'mouseover', function(e) {
        iwArray[i].open(map, this);
      });
    }

有效，但很丑 JSFiddle

    iwArray = [];

    iwArray[0] = new google.maps.InfoWindow({content: "w 0"});
    google.maps.event.addListener(marker[0], 'mouseover', function(e) {
      iwArray[0].open(map, this);
    });

    iwArray[1] = new google.maps.InfoWindow({content: "w 1"});
    google.maps.event.addListener(marker[1], 'mouseover', function(e) {   
      iwArray[1].open(map, marker[1]);
    });

    iwArray[2] = new google.maps.InfoWindow({content: "w 2"});
    google.maps.event.addListener(marker[2], 'mouseover', function(e) {
      iwArray[2].open(map, marker[2]);
    });

推荐答案

使用闭包:

 for (var i = 0; i < 3; i++) {
    (function(i){
       iwArray[i] = new google.maps.InfoWindow({content: "w "});
       google.maps.event.addListener(marker[i], 'mouseover', function(e) {
          iwArray[i].open(map, this);
       });
    })(i);
}

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