XML Parser organizing the elements in the keys - objective-c

Question

I'm reading the existing elements within my xml file and organizing within a NSMutableDictionary with keys and objects, the structure of my xml file is as follows:
<?xml version="1.0"?>
<root>
<elements>
<element1>something 0</element1>
<element2>somethingelse 0</element2>
<element3>anotherthing 0</element3>
</elements>
<elements>
<element1>something 1</element1>
<element2>somethingelse 1</element2>
<element3>anotherthing 1</element3>
</elements>
<elements>
<element1>something 2</element1>
<element2>somethingelse 2</element2>
<element3>anotherthing 2</element3>
</elements>
</root>
My code is bellow:
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
NSString *trim = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
if(!currentString){
currentString = [[NSMutableString alloc] init];
}
[currentString appendString:trim];
}
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{
if([elementName isEqualToString:#"root"]){
currentString = nil;
return;
}
if([elementName isEqualToString:#"elements"]){
key++;
currentString = nil;
}else{
NSString *keyp = [NSString stringWithFormat:#"%d",key];
NSMutableArray *listForelements = elementsArray[keyp];
if (keyp != nil) {
listForelements = [NSMutableArray array];
[elementsArray setValue:currentString forKey:keyp];
}
[listForelements addObject:currentString];
currentString = nil;
return;
}
currentString = nil;
The array elementsArray is returning me the following values:
0 = "anotherthing 0";
1 = "anotherthing 1";
2 = "anotherthing 2";
Instead of:
0 =
"something 0"
"somethingelse 0"
"anotherthing 0"
1 =
"something 1"
"somethingelse 1"
"anotherthing 1"
...
How I can solve this Problem?

Answer 1

After working with a significant amount of XML recently, I'd say your best bet is to look at a library like Ono. Parsing your XML is possible using the built in NSXMLParser and delegate methods but there is an unnecessary amount of things to keep track of compared to the following solution with Ono.
This solution makes use of a single class method that accepts the XML as NSData and returns an NSDictionary. This method has been created in a dedicated parsing class for whatever it's worth.
#import "Ono.h"
+ (NSDictionary *)parseData:(NSData *)data
{
NSError *docError;
ONOXMLDocument *document = [ONOXMLDocument XMLDocumentWithData:data error:&docError];
if (docError) {
// handle document creation error
NSLog(#"%#", docError.localizedDescription);
}
NSMutableDictionary *parsedData = [NSMutableDictionary dictionary];
[document enumerateElementsWithXPath:#"//elements" usingBlock:^(ONOXMLElement *element, NSUInteger idx, BOOL *stop) {
NSString *key = [NSString stringWithFormat:#"%d", idx];
NSMutableArray *items = [NSMutableArray array];
[element.children enumerateObjectsUsingBlock:^(ONOXMLElement *obj, NSUInteger idx, BOOL *stop) {
NSString *trimmedString = [obj.stringValue stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
[items addObject:trimmedString];
}];
[parsedData setObject:[items copy] forKey:key];
// [parsedData setObject:[items copy] forKey:#(idx)]; if you wanted to use an NSNumber as the key
[items removeAllObjects];
}];
return parsedData;
}
We first create an ONOXMLDocument using the +XMLDocumentWithData:error: method. Next we want to check that the document was created correctly and handle an error appropriately.
The NSMutableDictionary is created to store the parsed data and is returned by the method.
With regards to parsing, we first enumerate all of the ONOXMLElement instances that have the XPath elements. Using the XML provided, this gives us 3 items. We then create a key for the contained arrays to be stored by using the index provided by the enumeration block. We could also use an NSNumber as commented in the code.
Next, we create an NSMutableArray that will hold the content strings we intend to parse. We need to enumerate the children (element1, element2, element3) of each elements node. For convenience, we use ONOXMElement as the type of the argument obj so we can use the stringValue property which returns the content of the node.
As above, it's trimmed according to the desired character set, and then we add it to our items array. After enumerating the children of an element, we add a copy of the items array to the dictionary (since it's immutable the contents would change on the next iteration) and then remove all the objects so it is empty for our next iteration.
Once all iterations are complete, we return the dictionary of parsed XML.