在ios中使用XPX和touchXML的问题
[英]Issue with XPath with touchXML in ios
问题描述
I am trying to parse a xhtml file in ios using touchXML. 
我试图使用touchXML解析ios中的xhtml文件。 I am trying it for first time. 我是第一次尝试。 I have following format in XHTML: 我在XHTML中有以下格式：
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" lang="en">
<head>
<meta http-equiv="default-style" content="text/html; charset=utf-8"/>
<title>Contents</title>
<link rel="stylesheet" href="css/igp-widget-world.css" type="text/css"/>
</head>
<body>
<nav epub:type="toc"><h2>Contents</h2>
<ol epub:type="list">
<li><a href="s001-BookTitlePage-01.xhtml">Widget World</a></li>
<li><a href="s002-Copyright-01.xhtml">Copyright</a></li>
<li><a href="s003-TableOfContents-01.xhtml">Contents</a></li>
<li><a href="s004-Introduction-01.xhtml">Introduction</a></li>
<li><a href="s005-Part-001.xhtml">PART 1: EVENTS AND COMMANDS</a></li>
<li><a href="s006-Topic-001.xhtml">1: Timeline Events</a></li>
<li><a href="s007-Topic-002.xhtml">2: Counter Events</a></li>
<li><a href="s008-Topic-003.xhtml">3: Sprite Events</a></li>
<li><a href="s009-Part-002.xhtml">PART 2: QUESTIONS AND ANSWERS</a></li>
<li><a href="s010-Topic-004.xhtml">4: QAA True-False</a></li>
<li><a href="s011-Topic-005.xhtml">5: QAA True-False Multi</a></li>
<li><a href="s012-Topic-006.xhtml">6: QAA-Multichoice</a></li>
<li><a href="s013-Topic-007.xhtml">7: QAA Multi-Response</a></li>
<li><a href="s014-Topic-008.xhtml">8: QAA Association</a></li>
<li><a href="s015-Topic-009.xhtml">9: QAA Sequence</a></li>
<li><a href="s016-Topic-010.xhtml">10: QAA-Textmatch</a></li>
<li><a href="s017-Topic-011.xhtml">11: QAA-Textmatch Multi</a></li>
<li><a href="s018-Topic-012.xhtml">12: QAA Sort Word</a></li>
<li><a href="s019-Topic-013.xhtml">13: QAA Set</a></li>
<li><a href="s020-Part-003.xhtml">PART 3: INTERACTIVE WIDGETS</a></li>
<li><a href="s021-Topic-014.xhtml">14: Widgets: Horizontal Sliding Panel</a></li>
<li><a href="s022-Topic-015.xhtml">15: Widgets: Vertical Sliding Panel</a></li>
<li><a href="s023-Topic-016.xhtml">16: Widgets: Horizontal Tutorial Panel</a></li>
<li><a href="s024-Topic-017.xhtml">17: Widgets: Vertical Tutorial Panel</a></li>
<li><a href="s025-Topic-018.xhtml">18: Widgets: Vertical Scrolling Panel</a></li>
<li><a href="s026-Topic-019.xhtml">19: Widgets: Horizontal Scrolling Panel</a></li>
<li><a href="s027-Topic-020.xhtml">20: Widgets: XY Scrolling Panel</a></li>
<li><a href="s028-Topic-021.xhtml">21: Widgets: Locked Panel</a></li>
<li><a href="s029-Topic-022.xhtml">22: Widgets: Popups</a></li>
<li><a href="s030-Topic-023.xhtml">23: Widgets: Reveal</a></li>
<li><a href="s031-Topic-024.xhtml">24: Widgets: PopUp Panel</a></li>
<li><a href="s032-Colophon-01.xhtml">Colophon</a></li>
</ol>
</nav>
</body>
</html>
This is my xhtml file. 这是我的xhtml文件。 I implemented as follow: 我实施如下：
CXMLDocument* xmlDoc = [[CXMLDocument alloc] initWithContentsOfURL:myURL options:0 error:nil];
NSString* xpath = [NSString stringWithFormat:@"//html:a[contains(@href,'%@')]/../html:a", myValue];
NSArray* navPoints = [ncxToc nodesForXPath:xpath namespaceMappings:[NSDictionary dictionaryWithObject:@"http://www.w3.org/1999/xhtml/" forKey:@"xhtml"] error:nil];
I am trying to find value of <a> where <a href = my value. 我试图找到<a>值<a href = my value。
I am not sure where I am wrong the error is: 我不确定我错在哪里错误是：
XPath error : Undefined namespace prefix
XPath error : Invalid expression
Than I changed the xpath as follow: 比我更改xpath如下：
NSString* xpath = [NSString stringWithFormat:@"//html/a[contains(@href,'%@')]/../html/a", myValue];
: replaced by / . :替换为/ 。 It is not giving me error as above but not getting my content either. 它没有给我上面的错误，但也没有得到我的内容。
I don't know about XPATH. 我不知道XPATH。 In XML I only know about NSXMLParser . 在XML中我只知道NSXMLParser 。 Please help me to identify what's wrong in this? 请帮我确定一下这有什么问题？
Update 更新
As the answers I got till now I updated my code and did as follow: 作为我到目前为止的答案，我更新了我的代码并执行如下操作：
NSString* xpath = [NSString stringWithFormat:@"//html:a[@href = '%@']", href];
NSArray* navPoints = [ncxToc nodesForXPath:xpath namespaceMappings:[NSDictionary dictionaryWithObject:@"http://www.w3.org/1999/xhtml/" forKey:@"html"] error:nil];
and 和
NSString* xpath = [NSString stringWithFormat:@"//xhtml:a[@href = '%@']", href];
NSArray* navPoints = [ncxToc nodesForXPath:xpath namespaceMappings:[NSDictionary dictionaryWithObject:@"http://www.w3.org/1999/xhtml/" forKey:@"xhtml"] error:nil];
There is no error but I getting any object in the array. 没有错误，但我在数组中得到任何对象。 I don't think my XPath is working. 我认为我的XPath不起作用。
Update 2 更新2
The Xpath I am getting is as follow: 我得到的Xpath如下：
//xhtml:a[@href = 's001-BookTitlePage-01.xhtml']
or
//html:a[@href = 's001-BookTitlePage-01.xhtml']
also when I tried a xpath like: //html:a even though I am not getting all anchor tags. 当我尝试xpath时： //html:a即使我没有得到所有的锚标签。
** UPDATE 3** **更新3 **
I tried to check the XPath online http://www.xpathtester.com/test 我试着在线检查XPath http://www.xpathtester.com/test
I found following error on my XPath //html:a 我在XPath //html:a上发现以下错误//html:a
Exception occurred evaluting XPath: //html:a. Exception: XPath expression uses unbound namespace prefix html
Don't know what it means. 不知道这意味着什么。
Thanks 谢谢
2 个解决方案
解决方案1
0 2013-06-20 06:40:36
//a[@href="s001-Cover-01.xhtml"]/text()
返回'封面'但是您的文档格式不正确： <body>未关闭
解决方案2
0 2013-06-21 08:29:57
You registered the namespace as "xhtml", but use the prefix "html" in your query. 您将命名空间注册为“xhtml”，但在查询中使用前缀“html”。
Code for registering the namespace: 注册命名空间的代码：
NSArray* navPoints = [ncxToc nodesForXPath:xpath namespaceMappings:[NSDictionary dictionaryWithObject:@"http://www.w3.org/1999/xhtml/" forKey:@"xhtml"] error:nil];
Your XPath query: 您的XPath查询：
//html:a[contains(@href,'%@')]/../html:a
Change one of both lines to fit the prefixes: 更改两行中的一行以适合前缀：
//xhtml:a[contains(@href,'%@')]/../xhtml:a
Anyway, you should probably strip the last two axis steps which go back to the list item and look for anchor elements again. 无论如何，您应该去掉最后两个轴步骤，这些步骤返回到列表项并再次查找锚元素。 If there are two anchor elements (directly) inside the list item, you'd get both of them though only one matches the @href attribute. 如果列表项中有两个锚元素（直接），那么只有一个匹配@href属性，你才会得到它们。 Also, you wrote that you want to compare if they equal, so no need for contain() if they're really equal: 另外，你写道你要比较它们是否相等，所以如果它们真的相等则不需要contain() ：
//xhtml:a[@href = '%@']
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