Parsing XML with NSXMLParser and getting specific property value

Question

UPDATE: I decided to change my web service to output JSON, much easier to work with. I'll leave this open incase anyone can come up with a sensible solution, and in case it helps others.

I'm grabbing an XML file, parsing it, and trying to get content from specific tags:

//Grab the hosted XML
    NSError *error;
    NSURL *mainContentURL = [NSURL URLWithString:@"http://www.andrewlarking.co.uk/DigiCons/appContent.xml"];
    NSString *mainPageContents = [NSString stringWithContentsOfURL:mainContentURL encoding:NSUTF8StringEncoding error:&error];
    NSData *mainPageData = [mainPageContents dataUsingEncoding:NSUTF8StringEncoding];
    NSLog(@"mainPageData returned = %@", [[NSString alloc] initWithData:mainPageData encoding:NSUTF8StringEncoding]);

    //Parse the XML
    NSXMLParser *parser = [[NSXMLParser alloc] initWithData:mainPageData];
    [parser setDelegate:self];
    [parser parse];
}
}

-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict{
    NSLog(@"In parser");
    if([elementName isEqualToString:@"feb5Content"])
    {
        NSLog(@"In elementname");
        NSLog(@"valueforkey title = %@", [attributeDict valueForKey:@"page.title"]);
        self.dcViewControllerLabel.text = [attributeDict valueForKey:@"page.title"];
    }
}

All is good, but the value for key@"page.title" or @"title" returns null. Here is the XML:

    <feb5Content>
<page>
<title>I am a test title.</title>
<subTitle>I am the subtitle.</subTitle>
</page>
</feb5Content>

Any thoughts?

Ideally I'd like to be able to grab the content of various elements that exist within the element. So I could have title, subTitle, bodyText all under and I'd need to grab those. Each page of the app will have it's contents stored in a element.

Cheers.

I hope this will help you.. stackoverflow.com/questions/15534566/… — NULL
– NULL, Commented Dec 3, 2013 at 17:20

joern · Accepted Answer · 2013-12-04 07:09:20Z

1

That's because your page title is not an attribute of the <feb5Content> element. It is the value of the <title> element. So you have to listen to the start of the <title> element:

-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict{
   self.isTitleElement = [elementName isEqualToString:@"title"];
}

And then in the following method get the value inside the <title> element:

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
   if (self.isTitleElement) {
      NSLog(@"valueforkey title = %@", string);
      // store value so that it is not overwritten by the next title
      [self.pageTitles addObject:string];
   }
}

This method is called everytime that text is found inside an XML element. So you have to check if you are inside the <title> element when this method is called. That's why I included the ivar self.isTitleElement.

To store the page titles you can put them into an NSMutableArray ivar.

edited Dec 4, 2013 at 7:09

answered Dec 3, 2013 at 16:34

joern

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2 Comments

mrEmpty Over a year ago

Hello. This is partially working, in that it finds the correct string nit he tag, but it runs three times, and clears out the string on the second and third loop. The log shows: '2013-12-03 17:00:32.748 Digital Conversations[5711:70b] valueforkey title = I am a test title. 2013-12-03 17:00:32.748 Digital Conversations[5711:70b] valueforkey title = 2013-12-03 17:00:32.749 Digital Conversations[5711:70b] valueforkey title = '

joern Over a year ago

Yes, that's correct. It runs every time it finds a title element. You have to store the value somewhere (e.g. in an NSMutableArray) to keep them. See my edited answer.

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