Extract channel title from RSS feed using NSXMLParser - iphone

Question

how can I extract the title of a RSS channel while not getting in conflict with the title element of a news item?
If an element was found:
- (void)parser:(NSXMLParser *) parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict {
...
if ([elementName isEqualToString:#"channel") {
[currentChannel release];
currentChannel = nil;
currentChannel = [[NSMutableString alloc] init];
}
if ([elementName isEqualToString:#"item"]) {
...
}
}
If the end-tag was found:
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
if ([elementName isEqualToString:#"channel") {
[channel setObject:currentChannelTitle forKey:#"title"];
}
if ([elementName isEqualToString:#"item"]) {
...
}
Do the parsing stuff:
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
string = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
if ([currentElement isEqualToString:#"title") {
[currentChannelTitle appendString:string forKey:#"title"];
}
if ([currentElement isEqualToString:#"title"]) {
[currentTitle appendString:string];
}
...
}
And in the last part I have the problem. I have two "title" attributes. One for the "channel" element and one for the child element of it ("item"). But I need a distinction somehow. But how?

Answer 1

i think you want to get item title, in that case in viewDidload method take one bool type variable say flag in
viewDidload() method set flag=NO;
when during parsing you find a start element as "Item" set flag = YES, and In parser didendElement method when you found element as "Title", check that flag=YES or not. store only if it is YES.
and also in ParserDidEndElement when you find element as "Item" again set flag=NO;

Answer 2

I found another example to support different categories of the feed and I come up with the following solution:
First declare the variable in the *.h file.
#interface XMLParser : NSObject <NSXMLParserDelegate>{
...
NSMutableString * currentChannel;
}
In the *.m file synthesize and release the variable. In didStartElement ask which element you are currently working on. If it is a channel element, extract the title and store it in the above declared variable.
#implementation XMLParser
...
#synthesize currentChannel;
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict{
...
if ([elementName isEqualToString:#"item"]) {
...
}
// title is an attribute of the element channel
if ([currentElement isEqualToString:#"channel"]) {
[currentChannel appendString:[attributeDict objectForKey:#"title"]];
}
}
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{
if ([elementName isEqualToString:#"item"]) {
...
if ([currentChannel isEqualToString:#"Your Channel Name"]) {
if ([currentCategory isEqualToString:#"Your category name"]) {
[items addObject:[item copy]];
}
} else {
[items addObject:[item copy]];
}
}
}
In didEndElement ask if the item belongs to a specific channel, and if then add it only if it is the defined category. So you can add/show only rss feeds, if they belong to a certain category.
So i've not tested it, because the channel only have one category. So I don't have to ask for the channel titel, to show only defined categories from a specific channel. But I think that should work.