This is the “XMLParsing” example. In this app we will read data from xml file and display the data on the screen.
Step 1: Open the Xcode and create a new Xcode project using Navigation base application template. Give the application name “XML”. As shown in the figure below:
Step 2: Expand classes and notice Interface Builder created the RootViewController.h and RootViewController.m class for you. Expand Resources and notice the template generated a separate nib, RootViewController.xib.
Step 3: We need to add another file. Right-click on the Classes folder and choose Add -> New File. Under Cocoa Touch Class category choose Objective-C class. Name it Book.h and Book.m file.
This will be a very simple class that will take our dummy data file, read it in as an NSArray and provide some utility methods to access the data from the file.
#import <UIKit/UIKit.h>
@interface Book
: NSObject {
NSInteger bookID;
NSString *name;
//Same name as the Entity Name.
NSString *address;
//Same name as the Entity Name.
NSString *country;
//Same name as the Entity Name.
}
@property (nonatomic, readwrite) NSInteger bookID;
@property (nonatomic, retain) NSString *name;
@property (nonatomic, retain) NSString *address;
@property (nonatomic, retain) NSString *country;
@end
Step 4: We need to add Book.m file.
#import "Book.h"
@implementation Book
@synthesize name, address, country, bookID;
– (void) dealloc {
[country release];
[address release];
[name release];
[super dealloc];
}
@end
Step 5: We need to add another file. Right-click on the Resource folder and choose Add -> New File. Under Resource category choose View-XIB class. Name it BookDetailView.xib file. Double click the file and select Grouped table view.
Step 6: We need to add another file. Right-click on the Classes folder and choose Add -> New File. Under Cocoa Touch Class category choose Objective-C class. Name it XMLParser.h and XMLParser.m file. This will be a very simple class that will take our dummy data file, read it in as an NSArray and provide some utility methods to access the data from the file.
#import <UIKit/UIKit.h>
@class XMLAppDelegate, Book;
@interface XMLParser : NSObject {
NSMutableString *currentElementValue;
XMLAppDelegate *appDelegate;
Book *aBook;
}
– (XMLParser *) initXMLParser;
@end
Step 7: We need to open XMLParser.m file.
#import "XMLParser.h"
#import "XMLAppDelegate.h"
#import "Book.h"
@implementation XMLParser
– (XMLParser *) initXMLParser {
[super init];
appDelegate = (XMLAppDelegate *)[[UIApplication sharedApplication] delegate];
return self;
}
– (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName
attributes:(NSDictionary *)attributeDict {
if([elementName isEqualToString:@"Books"]) {
//Initialize the array.
appDelegate.books = [[NSMutableArray alloc] init];
}
else if([elementName isEqualToString:@"Book"]) {
//Initialize the book.
aBook = [[Book alloc] init];
//Extract the attribute here.
aBook.bookID = [[attributeDict objectForKey:@"id"] integerValue];
NSLog(@"Reading id value :%i", aBook.bookID);
}
NSLog(@"Processing Element: %@", elementName);
}
– (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
if(!currentElementValue)
currentElementValue = [[NSMutableString alloc] initWithString:string];
else
[currentElementValue appendString:string];
NSLog(@"Processing Value: %@", currentElementValue);
}
– (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
if([elementName isEqualToString:@"Books"])
return;
//There is nothing to do if we encounter the Books element here.
//If we encounter the Book element howevere, we want to add the book object to the array
// and release the object.
if([elementName isEqualToString:@"Book"]) {
[appDelegate.books addObject:aBook];
[aBook release];
aBook = nil;
}
else
[aBook setValue:currentElementValue forKey:elementName];
[currentElementValue release];
currentElementValue = nil;
}
– (void) dealloc {
[aBook release];
[currentElementValue release];
[super dealloc];
}
@end
Step 8: We need to add another file. Right-click on the Classes folder and choose Add -> New File. Under Cocoa Touch Class category choose UIViewController class. Name it BookDetailViewController.h and BookDetailViewController.m file.
#import <UIKit/UIKit.h>
@class Book;
@interface BookDetailViewController : UIViewController {
IBOutlet UITableView *tableView;
Book *aBook;
}
@property (nonatomic, retain) Book *aBook;
@end
Step 9: We need to open BookDetailViewController.m file.
– (UITableViewCell
*)tableView
:(UITableView
*)tv cellForRowAtIndexPath
:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier
= @"Cell";
UITableViewCell
*cell
= [tableView dequeueReusableCellWithIdentifier
:CellIdentifier
];
if (cell
== nil) {
cell
= [[[UITableViewCell alloc
] initWithFrame
:CGRectZero reuseIdentifier
:CellIdentifier
] autorelease
];
}
switch(indexPath.section
)
{
case 0
:
cell.text
= aBook.name;
break;
case 1
:
cell.text
= aBook.address;
break;
case 2
:
cell.text
= aBook.country;
break;
}
return cell;
}
– (NSString *)tableView:(UITableView *)tblView titleForHeaderInSection:(NSInteger)section {
NSString *sectionName = nil;
switch(section)
{
case 0:
sectionName = [NSString stringWithString:@"Name"];
break;
case 1:
sectionName = [NSString stringWithString:@"Address"];
break;
case 2:
sectionName = [NSString stringWithString:@"Country"];
break;
}
return sectionName;
}
Step 10: We need to open XmlAppDelegate.h file.
#import <UIKit/UIKit.h>
@interface XMLAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UINavigationController *navigationController;
NSMutableArray *books;
}
@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
@property (nonatomic, retain) NSMutableArray *books;
@end
Step 11: We need to open XmlAppDelegate.m file.
#import "XMLAppDelegate.h"
#import "RootViewController.h"
#import "XMLParser.h"
@implementation XMLAppDelegate
@synthesize window;
@synthesize navigationController, books;
– (void)applicationDidFinishLaunching:(UIApplication *)application {
NSURL *url = [[NSURL alloc] initWithString:@"http://chakrainteractive.com/mob/0-vin/Data.xml"];
NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithContentsOfURL:url];
//Initialize the delegate.
XMLParser *parser = [[XMLParser alloc] initXMLParser];
//Set delegate
[xmlParser setDelegate:parser];
//Start parsing the XML file.
BOOL success = [xmlParser parse];
if(success)
NSLog(@"No Errors");
else
NSLog(@"Error Error Error!!!");
// Configure and show the window
[window addSubview:[navigationController view]];
[window makeKeyAndVisible];
}
Step 12: Now build and run the code and view the Output in the Simulator.
You can download source code from here XML_Parsing
It’s been a back and forth saga with the 
