Difference between revisions of "IOS Swift"

Revision as of 19:46, 26 January 2015

swift note:
Basic
Var
var languageName: String = "Swift"
Constant
let version: Double = 1.0
:Int, :Bool

let components = "~/Documents/Swift".pathComponents
["~", "Documents", "Swift"]

let a = 3, b = 5
let res = "\(a) times \(b) is \(a * b)"

let dog = "dog"
var dog1 = dog + "1"
let a: Character = "a"
let b: Character = "b"
let ab = a + b

Array
var names = ["Anna", "Alex", 42]
var names: String[] = ["Anna", "Alex"]
var numOfLegs = ["ant": 6, "snake": 0]
for x in names {
  
}
for number in 1...5 {

}
for num in 0..<5 { //half close range

}
for (name, legs) in numOfLegs {

}
names += "Sam"
names += ["Hao", "Dan"]
names[0] = "x"
names[3...5] = ["x", "y", "z"]
numOfLegs["spider"] = 273
numOfLegs["spider"] = 8
Optionals
let possibleLegs: Int? = numOfLegs["aardvark"] //either get integer or nothing
if possibleLegs == nil {

} else {
  let legCount = possibleLegs! //forcing optional value to it's type
}
//A Simpler way
if let legCount = possibleLegs {

}
Switch legCount {
  case 0: //no break
  case 1: 
  case ExecButton: //match object
  case 1...5:
  case 2,4,6,8:
  default: //required
}
func sayHello(name:String = "default") { //give a default value

}
Tuples
(404, "Not found")
(2, "Banana", 0.42)
let (statusCode, message) = refresh()
Closures
func repeat(count: Int, task: () -> ()) {
  for i in 0..<count {
    task()
  }
}
repeat(2, {
  println("hello")
})
repeat(2) {
  println("hello")
}
Class
class Vehicle {
  var numOfWheels = 0 //stored properties
  var description: String { //computed properties, has to be var
    get { //get is optional
      return "\(numOfWheels) wheels"
    }
  }
}
let someVehicle = Vehicle() //Auto alloc
//inheritance
class Bicycle: Vehicle {
  init() { //initializer
    super:init()
    numOfWheels = 2
  }
  override var speed: Double {
    willSet {
      if newValue > 65.0 {
        println('warning too fast')
      }
    }
    didSet {
      //oldValue available
    }
  }
}
struct Rect {
  var origin: Point
  var size: Size
  var area: Double {
    return size.width * size.height
  }
  func isBiggerThanRect(other: Rect) => Bool {
    return self.area > other.area
  }
}
struct and class
1. struct cannot inherite
2. class is passed by reference. struct is passed by value
Constant and Variables
let window = Window(1.0, 1.0)
//The reference is a constant, cannot change the reference value
can do window.x = 1.0
cannot do window = Window(2.0, 2.0)

var point1 = Point(x: 0.0, y: 0.0) //Point is struct. can do point1.x = 1.0
let point2 = Point(x: 0.0, y: 0.0) // cannot do point2.x = 1.0