faster xml reading required in iPhone

Question

I have following code - methods to read xml files. But it works very slow for me. Isn't there any sufficient way to fetch & read data faster.

if(connectionRemaining)
{
    [self LoadingPopUp];
    NSURL *tmpURl=[NSURL URLWithString:[NSString stringWithFormat:@"%@getcategory.php",[iGolfAppDelegate getServerPath]]];
    NSMutableURLRequest *theRequest=[NSMutableURLRequest requestWithURL:tmpURl];
    NSURLConnection *conn=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
    if(conn)
        myWebData=[[NSMutableData data] retain];
    connectionRemaining=NO;
}

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
[myWebData setLength: 0];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[myWebData appendData:data];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[connection release];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection {
//  NSString *theXML = [[NSString alloc] initWithBytes: [myWebData mutableBytes] length:[myWebData length] encoding:NSUTF8StringEncoding];
//  NSLog(@"%@",theXML);[theXML release];   
if( myXMLParser )
    [myXMLParser release];
myXMLParser = [[NSXMLParser alloc] initWithData: myWebData];
[myXMLParser setDelegate: self]; [myXMLParser setShouldResolveExternalEntities: YES];
[myXMLParser parse];[connection release];[myWebData release];
}

#pragma mark
#pragma mark XMLParsing Methods
-(void)parser:(NSXMLParser*)parser didStartElement:(NSString*)elementName namespaceURI:(NSString*)namespaceURI qualifiedName:(NSString*)qualifiedName attributes:(NSDictionary*)attributeDict {
if([elementName isEqualToString:@"category"])
    categoryArray=[[NSMutableArray alloc]init];
else if([elementName isEqualToString:@"Prop_Category"])
    aCategory=[[Category alloc] init];
}

-(void)parser:(NSXMLParser*)parser foundCharacters:(NSString*)string {
if(!currentElementValue)
    currentElementValue=[[NSMutableString alloc] initWithString:string];
else
    [currentElementValue appendString:string];
}
-(void)parser:(NSXMLParser*)parser didEndElement:(NSString*)elementName namespaceURI:(NSString*)namespaceURI qualifiedName:(NSString*)qualifiedName {
if([elementName isEqualToString:@"category"])
{ [LoadingAlert dismissWithClickedButtonIndex:0 animated:YES]; [LoadingAlert release];[self categoryPickerDiplay]; return;  }
else if([elementName isEqualToString:@"Prop_Category"])
{ [categoryArray addObject:aCategory];[aCategory release];aCategory=nil; }
else{   
    [aCategory setValue:currentElementValue forKey:elementName];
    [currentElementValue release];currentElementValue=nil;
}

}

Let me clarify my question again.

I have observed that this way of reading xml is not sufficient. By using this way iPhone loads data very slowly. Because, iphone will read & compare each tag every time.

I want some faster XML Loading & Parsing.

Thanks in advance for sharing your knowledge with me

Answer 1

There's an example from Apple called XMLPerformance that illustrates libxml vs. NSXMLParser in terms of performance. Check out its implementation of libxml.

Answer 2

The SiesmicXML and TopSongs code samples from adc show some ways of parsing XML that cause a minimum of user wait time.

Answer 3

Have you looked at the libxml C library, or the TouchXML wrapper for it? Also, are you sure that it's the NSXMLParser that's causing your slowdown? You might want to do a quick runthrough using Instruments or Shark to profile the application and find the hotspots.