objective-c - 在 Objective-C 中解析简单的 XML

Question

我使用 ASIHttpRequest 连接到的网络服务器返回以下非常简单的 XML:

<element1>something</element1>
<element2>somethingelse</element2>
<element3>anotherthing</element3>

ASIHttpRequest 可以将其作为 NSData 或 NSString 返回。我需要解析信息，最简单的方法是什么？

谢谢

Answer 1

有一些 XML 解析器可用于 iOS NSXMLParser、libxml2(DOM 和 SAX)、TBXML、KissXML。您可以引用http://www.raywenderlich.com/553/how-to-chose-the-best-xml-parser-for-your-iphone-project选择最佳的 XML 解析器(速度和内存占用)。最简单的是 TBXML。 NSXMLParser 也很简单。

NSXMLParser* xmlParser = [[NSXMLParser alloc] initWithData:receivedXMLData];//init NSXMLParser with receivedXMLData
[xmlParser setDelegate:self]; // Set delegate for NSXMLParser
[xmlParser parse]; //Start parsing
[xmlParser release];

//Delegate Methods
//Have a instance variable NSMutableString* currentString; to hold data between elements and NSMutableArray* elementsArray; to hold parsed data

- (void)parserDidStartDocument:(NSXMLParser *)parser
{
    elementsArray = [[NSMutableArray alloc] init];
}

//store all found characters between elements in currentString mutable string
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    if(!currentString)
    {
        currentString = [[NSMutableString alloc] init];
    }
    [currentString appendString:string];    
}

//When end of XML tag is found this method gets notified
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    if([elementName isEqualToString:@"element1"])
    {
        [elementsArray addObject:currentString];
        [currentString release],currentString=nil;
        return;
    }
    if([elementName isEqualToString:@"element2"])
    {
        [elementsArray addObject:currentString];
        [currentString release],currentString=nil;
        return;
    }
    if([elementName isEqualToString:@"element3"])
    {
        [elementsArray addObject:currentString];
        [currentString release],currentString=nil;
        return;
    }
    [currentString release],currentString =nil;
}

//Parsing has ended
- (void)parserDidEndDocument:(NSXMLParser *)parser
{
    NSLog(@"Content of Elements Array: %@",elementsArray);
        [elementsArray release],elementsArray=nil;
}

- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
{
    UIAlertView* parseErrorAlert = [[UIAlertView alloc] initWithTitle:@"Parse Error" message:[NString stringWithFormat:"%@",[parseError localizedDescription]] delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    [parseErrorAlert show];
    [parseErrorAlert release];
}

您还有其他委托(delegate)方法，例如 parseErrorOccured。请参阅http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSXMLParser_Class/Reference/Reference.html

对于 TBXML:http://tbxml.co.uk/TBXML/API.html更新:实现了 parseError 委托(delegate)方法和有效的 xml 示例您在代码中发布的 XML 不是有效的 XML(您可以在线检查 XML 验证: http://validator.w3.org/#validate_by_input )，因此它将抛出 parseError 。以下是您发布的相关 XML 的有效 XML:

<?xml version="1.0"?>
<root>
 <element1>something</element1>
 <element2>somethingelse</element2>
 <element3>anotherthing</element3>
</root>