AS3 - 关于符号绑定的问题

发布于 2024-11-02 17:16:44 字数 471 浏览 2 评论 0原文

我是 AS3 的新手，无法弄清楚为什么这个循环没有按照它“应该”的方式运行。

for each (var s in [_set, _set.otherSet]) {
  for each (var f in [s.frame_top_mc, s.frame_bottom_mc]) {
    f.addEventListener(MouseEvent.CLICK, function( ):void {
      _score[f.category] += 1;
      madeSelection(f);
    });
  }
}

如何为每个匿名函数提供对 f 表示的每个对象的引用，而不是每次对 f 的简单引用？

具体来说，为什么匿名函数的每个副本都绑定到对 f 的单个引用？在这方面，AS3 与 JavaScript 到底有何不同（我应该说为什么）？

原文

I'm new to AS3, and can't figure out why this loop isn't behaving the way it "should."

for each (var s in [_set, _set.otherSet]) {
  for each (var f in [s.frame_top_mc, s.frame_bottom_mc]) {
    f.addEventListener(MouseEvent.CLICK, function( ):void {
      _score[f.category] += 1;
      madeSelection(f);
    });
  }
}

How can I give each anonymous function a reference to each object represented by f, rather than a simple reference to f each time?

Specifically, why is it that each copy of the anonymous function gets bound to a single reference to f? How (I should say why) exactly does AS3 differ from JavaScript in this regard?

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混浊又暗下来 2024-11-09 17:16:44

它需要像这样：

for each (var s in [_set, _set.otherSet]) {
  for each (var f in [s.frame_top_mc, s.frame_bottom_mc]) {
    f.addEventListener(MouseEvent.CLICK, function( e:MouseEvent ):void {
      _score[e.currentTarget.category] += 1;
      madeSelection(e.currentTarget);
    });
  }
}

问题是您的闭包正在关闭循环变量 f 本身，而不是循环中使用 f 引用的每个事物。循环完成后，f 将作为循环列表中最后一项的引用。 f 在创建闭包时不会取消引用，而是在执行时取消引用。

It needs to be like this:

for each (var s in [_set, _set.otherSet]) {
  for each (var f in [s.frame_top_mc, s.frame_bottom_mc]) {
    f.addEventListener(MouseEvent.CLICK, function( e:MouseEvent ):void {
      _score[e.currentTarget.category] += 1;
      madeSelection(e.currentTarget);
    });
  }
}

The problem is that your closure is closing over the loop variable f itself rather than each thing f is being used to reference within the loop. After the loop completes, f is left as reference to the last thing in the list you looped over. f is not being de-referenced when the closure is created, but when it's executed.

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