Spitting out objects from array in Objective-C - objective-c

Question

I'm quite new to classes and objects and I have a question:
I'm keeping track of books which can be input by textFields.
3 properties per book: Title, Author and Description.
What I'm trying to do is get all the objects of books in a NSMutableArray called: Collection.
(at the moment it's only 1 book (objectAtIndex:0)
Which is currently working but when I try to spit them back out I only get the description of the book. I'd love to get all the items (title, author, description).
What I've been wondering is: should I make a new (collection) class for example called BookCollection and make an array there? But how would I init it etc?
The code is below, help and tips are welcome!
(Started about a month ago)
Book.h
#import <Foundation/Foundation.h>
#interface Book : NSObject
#property(nonatomic,strong)NSString* title;
#property(nonatomic,strong)NSString* author;
#property(nonatomic,strong)NSString* description;
-(id)initWithTitle:(NSString*)newTitle withAuthor:(NSString*)newAuthor andDescription:(NSString*)newDesription;
Book.m
#import "Book.h"
#implementation Book
#synthesize title,author,description;
-(id)initWithTitle:(NSString*)newTitle withAuthor:(NSString*)newAuthor andDescription:(NSString*)newDesription{
self = [super init];
if (self) {
title = newTitle;
author = newAuthor;
description = newDesription;
}
return self;
}
#end
AppDelegate.m
#import "AppDelegate.h"
#implementation AppDelegate
#synthesize lblTitle,lblAuthor,lblDescription;
#synthesize collection;
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
// Insert code here to initialize your application
}
- (IBAction)buttonClick:(id)sender {
//alloc the array that will hold the books
collection = [[NSMutableArray alloc]init];
//create a new book
Book *newBook = [[Book alloc]initWithTitle:[lblTitle stringValue] withAuthor:[lblAuthor stringValue] andDescription:[lblDescription stringValue]];
//logging the items of the book
NSLog(#"%#",newBook.description);
NSLog(#"%#",newBook.title);
NSLog(#"%#",newBook.author);
//adding the book to the collection
[collection addObject:newBook];
//logging the book items from the collection
NSLog(#"%#",[collection objectAtIndex:0]);
//problem... only logs 1 item from the object...
}
#end
AppDelegate.h
#import <Cocoa/Cocoa.h>
#import "Book.h"
#interface AppDelegate : NSObject <NSApplicationDelegate>
#property(nonatomic,strong)NSMutableArray *collection;
#property (assign) IBOutlet NSWindow *window;
#property (weak) IBOutlet NSTextField *lblTitle;
#property (weak) IBOutlet NSTextField *lblAuthor;
#property (weak) IBOutlet NSTextField *lblDescription;
- (IBAction)buttonClick:(id)sender;
#end

Answer 1

You need to define your Book class's -description method.
When you call NSLog(#"%#", someObject), the object's -description method gets called and placed inside the %# format specifier. You'll want to override your Book class's -description method to print out all of the object's fields.
Have a look here for a good example.
To clarify, when you call:
NSLog(#"%#",newBook.description);
NSLog(#"%#",newBook.title);
NSLog(#"%#",newBook.author);
You are (quite correctly) logging each individual field. However, when you call:
NSLog(#"%#",[collection objectAtIndex:0]);
You are essentially writing:
NSLog(#"%#",newBook); // Gets an NSString from [newBook description];
And so you need to implement - (NSString *)desctiprion for the Book class to get the logging behaviour you are after.

Answer 2

Step 1 : remove collection = [[NSMutableArray alloc]init]; from - (IBAction)buttonClick:(id)sender and put it into applicationDidFinishLaunching method. Problem is You are initializing your array each time you add New Book to Collection Array.
To Iterate : all the objects of Array use following snippet
[collection enumerateObjectsUsingBlock:^(id obj, NSUInteger index, BOOL *stop){
Book *objBook = (Book *)obj;
NSLog(#"%#",objBook.description);
NSLog(#"%#",objBook.title);
NSLog(#"%#",objBook.author);;
}];

Answer 3

This Description Method is amazing! I had no idea it was even possible #PLPiper! Thank you
Although it gets harder... at this very moment I'm just logging it all out (for me as a developer). But for example... if I wanted all these properties in labels (string value). So if I wanted to spit them all out through my array, how would that work?
I've seen code that uses the following example(sort of) which I like and it's an easy-read.
for (int i = 0; (i<=[collection.count]); i++) {
[titleLabel setStringValue:[dateCollection objectAtIndex:i].title]
[authorLabel setStringValue:[dateCollection objectAtIndex:i].author]
[descriptionLabel setStringValue:[dateCollection objectAtIndex:i].description]
}
In theory this should work, but in practice I'm missing something here...