Objective-C

This blog post will introduce you to the concepts of iPhone App Development and Objective-C Programming. The simplicity and elegance of Apple's products is attracting many people to buy their products. And then successful programmers can become successful entrepreneurs if they could develop market-targeted apps.

The concept of MVC (Model-View-Controller) and the flexibility of programming for multiple devices (iPhone, iPad, Mac) just with Objective-C has given an opportunity to many programmers to expose their programming knowledge and contribute valuable apps to human society!

Basics of Object-oriented programming in Objective-C

Basic variable declaration:

int number = 1;

long long int number = 1;

const char myconst = ‘c’;

Datatypes & Format Specifiers:

Syntax for declaring an objective-c class interface:

@interface NewClassName: ParentClass {

ClassMembers;

}

ClassMethods;

@end

Example interface:

@interface BankAccount: NSObject {

…}

@end

Adding instance variable to a Class:

@interface BankAccount: NSObject

{

double accountBalance;

long accountNumber;

}

@end

Define class methods:

• Class Methods: preceded by ‘+'
• Instance Methods: preceded by ‘-‘

-(void) setAccountNumber: (long) y;

-(long) getAccountNumber;

-(void) setAccount: (long) y andBalance: (double) x; //Multiple parameters

Declaring the methods of a Objective-C class(Blueprint):

@interface BankAccount: NSObject

{

double accountBalance;

long accountNumber;

}

-(void) setAccountNumber: (long) y;

-(long) getAccountNumber;

-(void) setAccount: (long) y andBalance: (double) x;

@end

Syntax for Objective-C Class Implementation:

@implementation NewClassName

classMethods

@end

Defining the methods of a Objective-C Class:

@implementation BankAccount

-(void) setAccount: (long) y andBalance: (double) x

{

accountBalance = x;

accountNumber = y;

}

-(long) getAccountNumber

{

return accountNumber;

}

Declaring and initializing a class instance:

BankAccount *account1;

account1= [BankAccount alloc]; //allocate memory

account1= [BankAccount init]; //initialize the instance

This is equivalent to:

BankAccount *account1= [[BankAccount alloc] init];

How to access instance variables and methods:

• account1.accountBalance = 1000.00; //Instance Variable
• [account1 setAccount: 19986576 : 1000.00]; //Instance Method
• long theAccountNumberIs = [account1 getAccountNumber]; //Instance Method

Log messages for debugging:

NSLog(@“Account Number %li has a balance of %f”, accountNumber, accountBalance);