如何在Qt中使用QDomNodeList的foreach？ [英] How do I use foreach with QDomNodeList in Qt?

问题描述

我是Qt新手，每天都在学习新东西。

目前，我在空闲时间为我的诺基亚N900开发一个小应用程序。

一切都很好，我可以在设备上编译和运行Maemo应用程序。

我刚刚了解到 foreach 关键字在Qt中。 （我知道它不在C ++中，所以我没有想到它，直到我不小心偶然发现了一个Qt文档提到它）。
所以，我决定改变我很烦人和不可读的循环foreach，但是我失败了：

  QDomNodeList list = doc.lastChild（）。childNodes（）。at（1）。则firstChild（）的childNodes（）; 
 for（int x = 0; x  {
 QDomElement node = list.at（x）.toElement（）; 
 //用节点
做一些事
 
 
 $ b 
这是我试过的： 
 
 $ b $ 
  foreach（childDodes（））。 ））
 {
 //用节点
做一些事情} 
  
由于某些原因，上面的代码甚至没有编译。我从编译器得到神秘的错误消息。 
 
 
 
如果  
 
 
如果有人请向我解释如何得到它的权利？ foreach 循环不支持 QDomNodeList ，有办法处理XML文件，它支持 foreach  
 $ b  
    > / / code>在这种情况下执行以下操作： 
 
 
  EveCharacter chr; 
 chr.setName（node.attribute（EVE_NAME））; 
 chr.setId（node.attribute（EVE_CHARACTER_ID）.toInt（））; 
 acc-> addCharacter（chr）; 
  
其中acc的类型是 EveAccount ，将数据存储在 QList< EveCharacter> 中。
 
 
大写符号是编译时常量字符串。 
（我正在为EVE Online API创建一个客户端，这是从接收帐户字符XML 并解释它。）
 
 
 
这是我如何创建 doc ：
  QDomDocument doc; 
 doc.setContent（reply-> readAll（））; 
  
注意 reply 是一个 QNetworkReply * ，它是从 QNetworkAccessManager 返回的。
 
 
由于EVE API与XML协同工作，我在应用程序的许多地方做了很多与此类似的XML解析。
 
大多数XML可能有几百行，可以包含非常规数据模式，如 。
解决方案
   foreach  只支持容器类，所以你不能使用它与  QDomNodeList  。
 
 
 
我不确定你的实际目标，但是我找到  QXmlSimpleReader  和  QXmlStreamReader  为
 $ b 
 编辑以匹配问题编辑：你正在做的事情看起来像XPath或XQuery的主要候选人。查看  QtXmlPatterns  模块，这将给你一组字符节点，而不必循环所有其他节点。
I'm new to Qt and I'm learning something new every day.

Currently, I'm developing a small application for my Nokia N900 in my free time.

Everything is fine, I am able to compile and run Maemo applications on the device.

I've just learned about the foreach keyword in Qt. (I know it is not in C++, so I didn't think about it until I accidentally stumbled upon a Qt doc that mentioned it.)

So, I decided to change my quite annoying and unreadable loops to foreach, but I failed with this:
QDomNodeList list = doc.lastChild().childNodes().at(1).firstChild().childNodes();
for (int x = 0; x < list.count(); x++)
{
    QDomElement node = list.at(x).toElement();
    // Do something with node
}
This is how I tried:
foreach (QDomElement node, doc.lastChild().childNodes().at(1).firstChild().childNodes())
{
    // Do something with node
}
For some reason the above code doesn't even compile. I get cryptic error messages from the compiler.  

Could someone please explain to me how to get it right?

If the foreach loop doesn't support QDomNodeList, is there a way to handle XML files which supports foreach?

EDIT:

To clarify, // Do something with node is the following in this case:
EveCharacter chr;
chr.setName(node.attribute(EVE_NAME));
chr.setId(node.attribute(EVE_CHARACTER_ID).toInt());
acc->addCharacter(chr);
Where acc is of type EveAccount, which stores data in a QList<EveCharacter>.

The uppercase symbols are compile-time constant strings.

(I'm creating a client for the EVE Online API. This is from the method that receives the account characters XML and interprets it.)

This is how I create doc:
QDomDocument doc;
doc.setContent(reply->readAll());
Note that reply is a QNetworkReply* which is sent back from a QNetworkAccessManager.

However, as the EVE API works with XML, I do a lot of XML parsing very similar to this in many places in my application.

Most of the XMLs can be several hundred lines long and can contain quite non-regular data patterns, such as this one.
解决方案
foreach only supports the container classes, so you cannot use it with a QDomNodeList.

I'm not sure of you actual goal, but I find the QXmlSimpleReader and QXmlStreamReader to be the easiest way to deal with XML.

Edit to match question edit:

What you are trying to do looks like a prime candidate for XPath or XQuery.  Take a look at the QtXmlPatterns module this will give you a set of character nodes without having to loop through all the other nodes.

                        
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