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Sasha Goldshtein @goldshtnCTO, SELA Group blog.sashag.netFirst Steps in iOS Development

The iOS Platform

• 877,013+ of them Apps• UI, gestures, view

navigation, mediaCocoa Touch

• Location, threading, HTTP

Core Services

• Drivers, securityDarwin (kernel)

Platform Philosophy

User

• Consistent interface metaphors

• Always at home, on any device and in any app

• Seamless sync, backup, purchase

Developer

• Strong push to object orientation

• Just one language (Objective C)

• Strong separation of concerns in UI – MVC

Apple

• Full control over the ecosystem, hardware and software

• Ultimate arbitrator on whether an app is a fit for the App Store

iOS Devices and Versions

iPhone 3GS• iOS 3• iOS 4

Original iPad

iPhone 4/4S• iOS 5

iPhone 5• iOS 6

iPhone 5c/5s• iOS 7

September 2013:≈95% of iOS

devices run iOS 6

Devices and Resolutions

iPhone

3/3GS

3.5”

320×480

iPhone

4/4S

3.5”

640×960

iPhone

5/5c/5s

4”

640×1136

iPad 1/2

9.7”

1024×768

iPad Mini

7.9”

1024×768

iPad 3/4

9.7”

2048×1536

Developing for iOS

Xcode

Objective C

UIKit

self.title = [NSString initWithFormat:@"%d", n];[button setTitle:self.title forState:UIControlStateNormal];

Demo

Our First iOS App

Project Components

Generated files:Application delegateInitial view controllerMain storyboardProperty listFile for localizable stringsApplication icons

Xcode also adds basic frameworks to your app

iOS MVC Fundamentals

View

• Draws itself on the screen

• Contains generic UI-related data

View Controller

• Creates and coordinates views

• Populates views and reflects changes to the model

Model

• UI-agnostic classes

• Can be a bunch of objects, a database, a file, an Internet service

Outlets and Actions

Xcode connects views and controllersController manipulates views through outletsController receives events through actions

@interface MyViewController : UIViewController

@property (nonatomic, weak) IBOutlet UITextField *petName;

- (IBAction)getQuote;

@end

Demo

Connecting UI to Code

iOS Navigation Types

Tab bar controllerNavigation controller

Storyboards

The storyboard describes your application’s view controllers and connects them with segues

Passing Parameters

Usually the source view controller sets properties or calls methods on the destination view controller

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{ MySecondVC *vc = segue.destinationViewController; vc.itemToDisplay = [self selectedItem]; vc.delegate = self; // For callbacks}

Demo

Storyboards and Segues

Summary

Objective C fundamentalsView controllers, views, outlets, actionsStoryboards, seguesIt’s just another{language, IDE, UI framework}The rest is just details: data, networking, settings, table views, styling, …

QuestionsSasha Goldshtein @goldshtnCTO, SELA Group blog.sashag.net