This document provides an overview of iOS app development fundamentals including Objective-C, the building blocks of iOS apps like classes and objects, architectural patterns like MVC, and connecting interfaces to code. It covers key concepts like properties, protocols, delegates, app states, and using Interface Builder to connect user interfaces to code using outlets and actions. The document is intended as training for a beginner iOS developer to learn iOS and Objective-C fundamentals on their first day.

1. iOS App Development
Day #1 : Fundamentals of Objective C
By Madusha Perera

2. iOS and the technology
iOS - Mobile OS by Apple Inc (2007)
History
Steve Jobs worked in Apple
Left Apple and created Next
NeXTSTEP OS
After coming back to Apple initiated iOS

3. Brad Cox : ObjC
Scott Forstall: iOS lead
Steve Jobs
Chris Lattner : Swift

4. Layers of iOS
iPhone / iPad Hardware
UIKit.framework/M
apKit.famework/ ...
ImageIO.framewor
k/CoreVideo.fame
work/ ...
CoreData.framewo
rk/CFNetwork.fam
ework/ ...
Security.framewor
k/LibSystem ...
M
O
B
I
L
E
A
P
P

5. Objective C - Data types
● int/double/float … (C primitives)
● NSInteger/NSUInteger (OC primitives)
● NSNumber
● NSString
● NSArray …
**NSLog() format specifiers … i,d,u,@

6. Pointers in ObjC
NSString *spell1 = @“abracadabra”
NSString *spell2 = spell1;
abracadabraspell1
spell2

7. Properties in ObjC
A better way to define iVars.
@property(nonatomic,weak) NSString *name;
This automatically generates the following
_name
setName
getname (naming convention in ObC)
ARC

8. Property Attributes
strong,weak,atmoic,nonatomic, … etc
Strong:
The Obj will remain till Owner Obj lives in heap.
defaults are
in red
+1
Owner Obj Obj

9. weak :
The Obj can be destroyed independently. If that
happens the reference value automatically will
become nil.
Owner Obj Obj
nil
Low memory
warning !

10. nonatomic/atomic:
Time
Thread #1
Thread #2
Obj
setName
getName
nonatomic is faster

11. Methods are self documenting
Declaration
-(void) driveForDistance:(double)theDistance atSpeed:(double)speed;
+ for class methods
- for instance methods
Calling methods
[myRemoteCar driveForDistance:20 atSpeed:5];

12. Classes and Objects
A Class defines what an object
will look like when its created.
(define the states and behaviors.)
Objects are self contained modules that can be
easily used, re-used as building blocks for a
software application.

13. Interfaces and Implementation
classes (.h and .m files)
An ObjC class is defined in terms of an
interface and an implementation.
class
.h
.m
API exposed to other classes
Actual implementation of class

14. Interface (.h file)
@Interface NewClassname:ParentClass
<Protocol1>, <Protocol2> {
// private member variables
}
//properties
//public methods (instance or class methods)
@end

15. Implementation (.m file)
@implementation NewClassName
//method implementations
@end

16. Protocols
Source:http://rypress.com/tutorials/objective-c/protocols

17. Protocols cont.
@protocol ProtocolName <NSObject>
@required
//required method stubs
@optional
//optional method stubs
@end

18. Protocol cont.
// StreetLegal.h
#import <Foundation/Foundation.h>
@protocol StreetLegal <NSObject>
- (void)signalStop;
- (void)signalLeftTurn;
- (void)signalRightTurn;
@end
Source:http://rypress.com/tutorials/objective-c/protocols

19. Protocol cont.
// Bicycle.h
#import <Foundation/Foundation.h>
#import "StreetLegal.h"
@interface Bicycle : NSObject <StreetLegal>
- (void)startPedaling;
@end
// Bicycle.m
#import "Bicycle.h"
@implementation Bicycle
- (void)signalStop {
NSLog(@"Bending left arm downwards");
}
- (void)signalLeftTurn {
NSLog(@"Extending left arm outwards");
}
- (void)signalRightTurn {
NSLog(@"Bending left arm upwards");
}
- (void)startPedaling {
NSLog(@"Here we go!");
}
@end
Source:http://rypress.com/tutorials/objective-c/protocols

20. Design Patterns : Delegate
Design Pattern : A general reusable solution to
a commonly occurring problem.

21. Delegate Pattern
Delegate
Delegator

22. Where it all starts : main()
Hands control to the UIKit framework.

23. iOS App Development
Day #2 : Building an App with UI

24. Where it all starts : main()
Hands control to the UIKit framework.

25. Delegate Pattern in use

27. Architectural Pattern : MVC
Controller
Accept user input and react orchestrate
View
Model
Business Logic + Data
Core functionality and data
Display information to the user

28. States

29. Launched or
terminated
Running but not
receiving events
(phone call/sms)
Running in
background if
permits
Source:https://developer.apple.com

30. Source:https://developer.apple.com

31. IBOutlets and IBAction
IB : Interface Builder
Outlet and IBAction are just flags to tell the
xcode this is to do with the UI

32. Connecting the things
Lets create a small app ...