Class 2

• Continue Calc Demo
• Learn about MVC
• Calc Cont:
  • Array <T>
  • "Computed" properties 
  • Switch
  • Functions as types
  • Closure syntax for defining functions "on the fly"
  • Methods with the same name but different argument types 
  • Auto layout 
• Demo
  • Optionals automatically are initialized with nil
  • ? vs. !
    • If we had used a ? we would have to unwrap every instance 
    • ! unwraps everything from the start (implicitly unwrapped optional)
  • Enter key
    • Copy and paste "3" button 
    • Replace 3 with Return symbol found in Special Characters menu
    • //Ctrl-drag from button to in class below last action, Action, Name: enter, Type: UIButton, Touch Up Inside, Argument: None
    • //right click on button and disconnect enter button from appendDigit
    • @IBAction func enter (){
      • inMiddleOfTyping = false
      • operandStack.append(displayValue)
      • println("operandStack = \(operandStack)")
    • }
    • Above action func enter, var operandStack*(: Array<Double>) = Array<Double>()
    • //if a type can be inferred, it should be 
    • //Need to convert string to double:
    • Below action, var displayValue: Double {
      • get{
        • return NSNumberFormatter().numberFromString(display.text!)!.doubleValue
      • }
      • set{
        • display.text = "\(newValue)"
        • inMiddleOfTyping = false
      • }
    • }
  • Operation keys
    • Copy and paste "9" button
    • Right click on button and disconnect button from appendDigit
    • Replace 9 with X symbol found in Special Characters menu
    • Ctrl-drag from button to in class above var operandStack, Action, Name: operate, Type: UIButton, Touch Up Inside, Argument: Sender
    • Copy and paste "X" button 3x and replace X with + - and divide symbols
    • @IBAction func operate(sender: UIButton) {
      • let operation = sender.currentTitle!
      • if inMiddleOfTyping {
        • enter()
      • }
      • switch operation {
      • case "x": performOperation{ $0 * $1 }
      • case "/": performOperation{ $1 / $0 }
      • case "+": performOperation{ $0 + $1 }
      • case "-": performOperation{ $1 - $0 }
      • default: break
      • }
    • }
    • func performOperation(operation: (Double, Double) -> Double){
      • if operandStack.count >= 2 {
        • displayValue = operation(operandStack.removeLast(), operandStack.removeLast())
        • enter()
      • }
    • }
  • Additional Operations
    • Copy and Paste row of operation buttons and line up next to them
    • Remove characters but leave buttons
    • In bottom button label with Square Root symbol found in Special Characters menu
    • in switch operation above default
      • case " √": performOperation { sqrt($0)}
    • Copy/Paste func performOperation and edit to make it take one Double
    • func performOperation(operation: Double -> Double){
      • if operandStack.count >= 1 {
        • displayValue = operation(operandStack.removeLast())
        • enter()
      • }
    • }
  • Layout
    • Copy/Paste a number to fill the last button space, delete and remove appendDigit (try to make this a "." button)
    • Select all of the buttons, make sure they are lined up to left edge and below the label
    • In Add New Constraints menu
      • check off Equal Widths 
      • check off Equal Heights
      • make all beams for spacing solid
      • make all sides of spacing 8
    • Use warning labels to select "Apply to all views in container" and "Update Frame"
    • This demo was not a good representation of MVC because all of the calculator functions are not really UI. I assume that we should have put them all in  a separate swift file. 
• MVC
  • Model - What your application is, but not how it is displayed 
  • Controller - How your model is presented to the user (UI logic, specific)
  • View - Your Controller's minions (generic UI elements )
  • It's all about know where things should go and managing communication between the camps
  • Model and View do NOT interact, Controller can always talk to either (only sorta vice verse)
    • Controller to View is an Outlet
    • Model is UI independent
    • View elements are too generic to communicate with the Model
    • View to Controller is blind and structured (Action to Target)
      • Sometimes View needs to sync with the Controller (will, should, did) View doesn't know specifics so will delegate them to the Controller (the delegate is set via a protocol and is blind to class)
    • Views should not own the data they are displaying: data should be in the Model, it has nothing to do with the UI (data at, count)
      • View wants to know how much data there is, asks Controller for data source, Controller asks Model, Model tells Controller amount, Controller tells View the amount 
    • Model is UI independent, should not talk to Controller 
    • If Model needs to communicate changes to the Controller, it uses a radio station-like broadcast mechanism
      • Notification & Key Value Observing (KVO): when a Model has a change it will broadcast that change and the Controllers and/or other Models will tune in to the stuff they are interested in. (Don't want a View to do this)
    • In multiple view apps you will need more complicated MVC groups 
    • An entire MVC can work as a View for another MVC

Class 1

Platform Components 

• Tools: XCode
• Languages: Swift (and Obj-C)
• Frameworks: Foundation, Core Data, UIKit: main framework , Core Motion, Map Kit
• Design Strategy: MVC - Master View Controller

Demo

• Build a Calculator 
  • Single View Application
    • Product Name: Calculator 
    • Org Name: FisherMichaels 
    • Org ID: com.FisherMichaels
    • Bundle ID: com.FisherMichaels.Calculator
    • Language: Swift
    • Device: Universal
  • Storyboard 
    • Drag in Label to top left guidelines, resize to right guideline, Type "0", Right justify, 32 pt font, resize box to fit
    • Ctrl-drag from label to View, Trailing Space to container margin, Ctrl-drag from label to View, Leading Space to container margin, Ctrl-drag from label to View, Top Space to container margin
    • In Doc Outline, look for problem areas
      • Update Constraints: Make it look like my arbitrary decisions said it was, rarely use this
      • Reset to Suggested Constraints: Removes already set constraints 
      • Update Frames: Change the Label to how it should be
    • Open Assistant Editor,  clear out class ViewController{
      • //Ctrl-drag from label to in class, Outlet, Name: display
      • @IBOutlet weak var display: UILabel!
      • }
    • Drag in Button to mid-left, name "7", resize and embiggen font
      • //Ctrl-drag from button to in class, Action, Name: appendDigit, Type: UIButton, Touch Up Inside, Argument: Sender 
      • @IBAction func appendDigit(sender: UIButton){
        • var inMiddleOfTyping: Bool = false
        • let digit = sender!.currentTitle
        • if inMiddleOfTyping {
          • display.text = display.text! + digit
        • } else {
          • display.text = digit
          • inMiddleOfTyping = true
        • }
        • }
    • Copy/Paste and guideline up to build numberpad, move whole pad and line up to below label, left