IOS Apps With Swift

iOS applications
with Swift
Make swiftly iOS development

Telerik Academy Plus
Telerik Academy
http://academy.telerik.com

About Me


Doncho Minkov
 Senior Technical Trainer
@ Telerik Software Academy
 Contestant in the Informatics
competitions
 Experience with Web and Mobile
apps
 Proficient with JavaScript and .NET
 Email: doncho.minkov [at]
telerik.com
 Blog: http://minkov.it

Table of Contents
Swift overview
 Language syntax and specifics


 Variables, structures and optional
values
 Control structures: if-else, switch,
loops
 Functions as first-class objects,
closures, etc…
 OOP: classes, protocols, enums,
extensions
 Syntactic sugar: destructuring
assignments

Swift Overview
What and Why?

Swift Overview


Swift is an innovative new
programming language for Cocoa
and Cocoa Touch
 Writing code is interactive and fun
 The syntax is concise yet expressive
 Apps run lightning-fast



Swift can be used for creating
brand-new iOS and OS X apps
 Or to add features to applications
written with Objective-C

Swift Overview


Swift was introduced at WWDC
2014 as the "new way to create
apps for iPhone and iPad"






Objective-C without the C
Descendant to Objective-C
No pointers
Functions as first-class objects
Influenced from many modern
languages:
 JavaScript, Objective-C, C#, Python,
Scala, etc…

Swift Experiment
Techniques


Since Swift is pretty new and still
needs exploring Apple has
provided ways to experiment the
new features:
 REPL (Read Eval Print Loop)
 Run swift code from the Terminal

 Xcode interactive Playground
 Immediate code evaluation, while
typing

Using the Swift REPL


To use the REPL of Swift follow the
steps:
1. Start $Terminal.app
swift
2. Type
3. Type code directly inside the
Terminal
4. The output is shown directly on
the Terminal
$ swift print-

.You

can primes.swift
also execute code from a
swift file:

Using the Swift REPL
Live Demo

Using the Swift
Playground


Apple has provided a Playground for
experimenting with Swift features
inside Xcode
 Write code and receive immediate
result
 Great for exploring Swift features and
research
 Allows fast testing of features and
syntax

Going to the
Playground
Live Demo

Swift Syntax and
Specifics
Laying
the groundwork

Swift Syntax Overview


Swift syntax:
 Variables and contants
 Control structures
 If-else, loops, switch

 Data structures
 Arrays, dictionaries, sets

 Classes and structures
 Init functions, methods, properties,
fields

 OOP
 Protocols, extensions, inheritance

Data types, Variables
and
Constants
var and let, primitive and reference,
functions

Data Types in Swift


Swift supports the common data
types, coming from Objective-C
 Int for creating integers numbers
 UInt for creating unsigned integer
numbers
 Float, Double for floating-point
numbers
 Bool for Boolean values
 [] for array, [Int] for array of integers



Swift supports both structures and
classes
 Structures create primitive types



Data Types, Variables
and Constants

Swift provides two keywords for
creating variables:
 let and var



var creates a mutable variable
 Its value can be changed any time
 The type can be provided or inferred



let creates immutable variable
 If the type is struct, its value cannot
be changed
 If the type is object, it can be changed
only internally

Using let and var


Creating a variable of type integer:
 Using let
let numberOfCourses: Int = 15
numberOfCourses = 16 // compiler error

 Using var
var count :Int = 15
count++ //this is Ok

 Variable types are inferred
 The compiler will understand that you
want Int
 Works with let and var
let numberOfCourses = 15

var count = 15

Using var and let
Live Demo

Defining Functions in
Swift
 Functions in Swift have the following
syntax:
 Function
returning
void:
func
printMessage(message:
String)
{
println(String(format: "Message: %@", message))
}
 Function returning integer:
func sum(x: Int, y: Int) -> Int {
return x + y
}

 Function with parameters put inside
ansum(numbers:
array: Int…) -> Int {
func
var sum = 0
for number in numbers { sum += number}
return sum
}

Functions in Swift
Live Demo



Control Flow
Structures:
if-else and switch

Swift supports the standard
control flow structures:
if-else
if condition {
//run code
}
else if condition2
{
//run other code
}
else {
//run third code
}

switch
switch language {
case "Objective-C",
"Swift":
println("iOS")
case "Java":
println("Android")
case "C#":
println("Windows Phone")
default:
println("Another
platform")
}

If-else and Switch
Live Demo



Control Flow
Structures: Loops

Swift supports the standard
control flow structures:
 for loop
for i in 0...11 {
//i gets the values from 0 to 11, inclusive
}
for i in 0..<11 {
//i gets the values from 0 to 10, inclusive
}

 while loop
while condition {
//run code
}

Swift Data
Structures

Swift Data Structures


Swift has built-in arrays and
dictionaries
 let creates immutable
dictionary/array
 var creates mutable dictionary/array

numbers: [Int] = [1, 2, 3, 4, 5]
let
Immutable
arrays:
numbers[2] = -1 //compile error
numbers.append(6) //compile error



Mutable arrays:

var names: [String] = ["Doncho", "Ivaylo"]
names.append("Nikolay") //Doncho, Ivaylo, Nikolay
names.append("Pesho")
//Doncho, Ivaylo, Nikolay, Pesho
names[3] = "Evlogi"
//Doncho, Ivaylo, Nikolay, Evlogi



Same for dictionaries

Arrays and
Dictionaries
Live Demo

Classes and
Structures
Introducing
the OOP principles in Swift

Swift Classes


Swift is an OOP language

 Has classes, structures and
protocols
class Square{
var x: Float
var y: Float
var side: Float
init(x: Float, y: Float, side: Float){
self.x = x
self.y = y
self.side = side
}
func calcArea() -> Float{
return self.side * self.side
}
}

Creating Simple
Classes
Live Demo



Protocols in Swift

Protocols in Swift are pretty much
the same as in Objective-C

 Almost like interfaces in C# and Java
 They provide a public interface for the
conforming classes to implement
protocol Movable{
func moveToX(x: Int, y: Int)
func moveByDx(dx:Int, dy: Int)
}
class Shape: Movable{
func moveToX(x: Int, y: Int){
//implementation
}
func moveByDx(dx: Int, dy: Int){
//implementation
}
}

Protocols in Swift
Live Demo

UIKit Animations

UIKit Animations







A limited number of animatable
properties
Custom animatable properties cannot be
created
All animations are disabled by default
Animations are enabled only when using
let view = UIView(frame: CGRectMake(x, y, w, h))
special
constructs
UIView.animateWithDuration( 1.0
animations: {
let frame = CGRectMake(x + 100,
y + 100,
w,
h)
view.frame = frame
});

UIKit Animations:
Animation Blocks


UIKit Animations with Animation Blocks
UIView.animateWithDuration( 1.0
delay: 1.0
options:
UIViewAnimationOptions.CurveEaseIn
animations: {
let frame = CGRectMake(x + 100,
y + 100,
w,
h)
view.frame = frame
},
completion: {
view.alpha = 0.5
});

UIKit Animations
Live Demo

iOS Apps with Swift
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