as3 xml检查元素是否存在

I want to check if the element in this structure exists for each child. The problem is that the children don't have the same name (product,prepack) and I don't want to change the order. Additionally I can't change the XML structure.

我想检查每个子节点中是否存在此结构中的元素。问题是孩子们没有相同的名字（产品，预包装），我不想改变订单。另外，我不能改变XML结构。

<items>
    <product>
        <resourceImages>
            <image />
        </resourceImages>
    </product>
    <product>
        <resourceImages>
            <image />
        </resourceImages>
    </product>
    <prepack>
        <resourceImages />
    </prepack>
    <product>
        <resourceImages>
            <image />
        </resourceImages>
    </product>
    <prepack>
        <resourceImages />
    </prepack>
</items>

3 个解决方案

#1

Like this?

喜欢这个？

for each(var item : XML in xmlData.children())
{
    var hasImages : Boolean = (item.resourceImages.children().length() > 0);

    if(hasImages)
        trace("item has images")
}

#2

It appears there are two ways, but the check using undefined seems preferable.

看来有两种方法，但使用undefined的检查似乎更可取。

if (item.image.length() > 0)

要么

if (item.image != undefined)

But beware, this always evaluates to true regardless if the node exists.

但请注意，无论节点是否存在，这始终都会为true。

if (item.image)

Which is weird considering the undefined check.

考虑到未定义的检查，这很奇怪。

#3

Depends also how is your first loop, but you can also check if the node is not undefined :

还取决于你的第一个循环，但你也可以检查节点是否未定义：

var xml:XML=<items>
    <product>
        <resourceImages>
            <image />
        </resourceImages>
    </product>
    <product>
        <resourceImages>
            <image />
        </resourceImages>
    </product>
    <prepack>
        <resourceImages />
    </prepack>
    <product>
        <resourceImages>
            <image />
            <image />
        </resourceImages>
    </product>
    <prepack>
        <resourceImages />
    </prepack>
</items>;

//loop on all all resourceImage node
for each (var resourceImageXML:XML in xml..resourceImages){
    // and check if node if defined
    if (resourceImageXML.image != undefined) {
        // ok node have image
    }
}

#1