NSXMLParser: Parsing XML file shows two identical arrays - iphone

Question

Maybe someone can help ...
I have a problem with the fact that during the parsing of the XML file we have two arrays. Such is the construction of TWO identical returns an array:
xmlcont = [[XMLController alloc] loadXMLByURL:#"http://link_to_XML_file.xml"];
I have the following files:
Constants.h
#import <Foundation/Foundation.h>
extern NSString * const ITEM;
extern NSString * const TITLE;
extern NSString * const IMAGE;
extern NSString * const DESCRIPTION;
extern NSString * const TEXT;
#interface Constants : NSObject
{
}
#end
Constants.m
#import "Constants.h"
#implementation Constants
NSString * const ITEM = #"item";
NSString * const TITLE = #"title";
NSString * const IMAGE = #"image";
NSString * const DESCRIPTION = #"description";
NSString * const TEXT = #"text";
- (void)dealloc
{
[super dealloc];
}
#end
myNews.h
#import <Foundation/Foundation.h>
#interface myNews : NSObject
{
NSString *itemTitle;
NSString *itemImageUrl;
NSString *itemDescription;
NSString *itemText;
}
#property (nonatomic, retain) NSString *itemTitle;
#property (nonatomic, retain) NSString *itemImageUrl;
#property (nonatomic, retain) NSString *itemDescription;
#property (nonatomic, retain) NSString *itemText;
#end
myNews.m
#import "myNews.h"
#implementation myNews
#synthesize itemTitle;
#synthesize itemImageUrl;
#synthesize itemDescription;
#synthesize itemText;
#end
XMLController.h
#import <Foundation/Foundation.h>
#class Constants;
#class myNews;
#interface XMLController : NSObject
{
NSMutableString *currentNodeContent;
NSMutableArray *newsArray;
NSXMLParser *parser;
myNews *currentNew;
}
#property (readonly, retain) NSMutableArray *newsArray;
-(id)loadXMLByURL:(NSString *)urlString;
#end
XMLController.m
#import "XMLController.h"
#import "Constants.h"
#import "myNews.h"
#implementation XMLController
#synthesize newsArray;
-(id)loadXMLByURL:(NSString *)urlString
{
newsArray = [[NSMutableArray alloc] init];
NSURL *url = [NSURL URLWithString: urlString];
parser = [[NSXMLParser alloc] initWithContentsOfURL: url];
[parser setDelegate:(id)self];
[parser parse];
return self;
}
-(void) parser:(NSXMLParser *)parser
didStartElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qName
attributes:(NSDictionary *)attributeDict
{
if ([elementName isEqualToString: ITEM])
{
currentNew = [myNews alloc];
currentNodeContent = [[NSMutableArray alloc] init];
}
}
-(void) parser:(NSXMLParser *)parser
didEndElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qName
{
if ([elementName isEqualToString: TITLE])
{
currentNew.itemTitle = currentNodeContent;
}
if ([elementName isEqualToString: IMAGE])
{
currentNew.itemImageUrl = currentNodeContent;
}
if ([elementName isEqualToString: DESCRIPTION])
{
currentNew.itemDescription = currentNodeContent;
}
if ([elementName isEqualToString: TEXT])
{
currentNew.itemText = currentNodeContent;
}
if ([elementName isEqualToString: ITEM])
{
[newsArray addObject:currentNew];
[currentNew release];
currentNew = nil;
[currentNodeContent release];
currentNodeContent = nil;
}
}
-(void) parser:(NSXMLParser *)parser
foundCharacters:(NSString *)string
{
currentNodeContent = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}
#end
myAppDelegate.h
#import <UIKit/UIKit.h>
#import "MainViewController.h"
#import "DetailViewController.h"
#class MainViewController;
#class DetailViewController;
#interface myAppDelegate : NSObject <UIApplicationDelegate>
{
UIWindow *window;
UINavigationController *myNavigationController;
MainViewController *myMainViewController;
DetailViewController *myDetailViewController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet UINavigationController *myNavigationController;
#property (nonatomic, retain) IBOutlet MainViewController *myMainViewController;
#property (nonatomic, retain) IBOutlet DetailViewController *myDetailViewController;
#end
myAppDelegate.m
#import "myAppDelegate.h"
#import "myNews.h"
#import "MainViewController.h"
#import "DetailViewController.h"
#implementation myAppDelegate
#synthesize window;
#synthesize myNavigationController;
#synthesize myMainViewController;
#synthesize myDetailViewController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
[window addSubview:myNavigationController.view];
[window makeKeyAndVisible];
return YES;
}
- (void)dealloc
{
[window release];
[myNavigationController release];
[myMainViewController release];
[myDetailViewController release];
[super dealloc];
}
#end
MainViewController.h
#import <UIKit/UIKit.h>
#import "XMLController.h"
#interface MainViewController : UIViewController
{
XMLController *xmlcont;
}
#end
MainViewController.m
#import "MainViewController.h"
#import "myNews.h"
#implementation MainViewController
- (void)viewDidLoad
{
[super viewDidLoad];
xmlcont = [[XMLController alloc] loadXMLByURL:#"http://link_to_XML_file.xml"];
NSLog(#"array = %#", [xmlcont newsArray]);
for (myNews *oneNew in [xmlcont newsArray]) {
NSLog(#"URL = %#", [oneNew itemImageUrl]);
}
}
- (void)viewDidUnload
{
[super viewDidUnload];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (void)dealloc
{
[super dealloc];
}
#end
XML file:
<?xml version="1.0" encoding="UTF-8"?>
<channel>
<item>
<title>news 1</title>
<image>http://link_to_JPG_file_1.jpg</image>
<description>description 1</description>
<text>text 1</text>
</item>
<item>
<title>news 2</title>
<image>http://link_to_JPG_file_2.jpg</image>
<description>description 2</description>
<text>text 2</text>
</item>
</channel>
As a result, the implementation of the output I see:
2011-07-14 13:18:27.785 my[18673:207] array = (
"<myNews: 0x4e28dc0>",
"<myNews: 0x4e29080>"
)
2011-07-14 13:18:27.787 my[18673:207] URL = http://link_to_JPG_file_1.jpg
2011-07-14 13:18:27.818 my[18673:207] URL = http://link_to_JPG_file_2.jpg
2011-07-14 13:18:27.959 my[18673:207] array = (
"<myNews: 0x4b5a010>",
"<myNews: 0x4b5a310>"
)
2011-07-14 13:18:27.960 my[18673:207] URL = http://link_to_JPG_file_1.jpg
2011-07-14 13:18:27.963 my[18673:207] URL = http://link_to_JPG_file_2.jpg
MainWindow.xib
Screenshot MainWindow.xib
Please tell me where I could be wrong?

Answer 1

You're getting viewDidLoad called twice (which isn't necessarily a bug). You just need to add some logic to only load your XML once.
- (void)viewDidLoad
{
[super viewDidLoad];
if (nil == xmlcont) {
xmlcont = [[XMLController alloc] loadXMLByURL:#"http://link_to_XML_file.xml"];
NSLog(#"array = %#", [xmlcont newsArray]);
for (myNews *oneNew in [xmlcont newsArray]) {
NSLog(#"URL = %#", [oneNew itemImageUrl]);
}
}
}
PS If you add this code and still get the output twice then you're making two versions of the ViewController.