Developing iOS9 Apps with Swift - Standford iTunesU

[sohilpandya]

Apparently, these are some of the best lectures on Swift and iOS development, might be worth investing time into it.

Its free!

• [x] leave feedback on the introduction video

[sohilpandya]

The first lecture is 1 hr 17min, but giving myself 2 hours to go through it, will post the outcome below

[sohilpandya]

In chapter 1, the student is taken through the process of building a calculator.

pre req

• OOP programming experience mandatory (Object-Orientated Programming)
• Xcode. My version of Xcode is 8.1, you should be able to follow on a different version, although the screenshots may not be exactly the same.

Things we'll learn in this course

• [ ] Xcode
• [ ] Swift
• [ ] UIKit
• [ ] MVC

Note that I have done next to no programming for iOS, I am a JavaScript developer

What's in iOS?

1. Core OS	2. Core Services

3. Media	4. Cocoa Touch

Things we'll learn in lecture 1

• [x] Create a Project in Xcode
• [x] Building a UI
• [x] Use iOS Simulator

Create a Project

1. select new project	2. select type of application

3. select project name	4. voila!

Xcode screen layout

Setup Provisioning by registering an Apple ID

• Add an account if you don't have one setup. (any iTunes account will work, we do not require the special developers account)
• Plug in your iPhone
• You should now be able to link your phone to this registered account

Known Issue If you are having trouble connecting your phone or Xcode showing an error message like such: Then please select your iPhone from the dropdown list shown here:

This will solve the issue Known Issue

ViewController.swift is our controller & Main.storyboard

Model

• What our computer does (UI Independent)

View Main.storyboard

• User interface (buttons)

Controller ViewController.swift

• Glue between Model and View
  • listens to UI
  • makes decision
  • updates the model. (back and forth relationship)

Interface Builder: In iOS you don't code the visuals, just drag and drop them (wire them onto the logic afterwards)

Our first Button

• Drag and drop a button from the utilities list
• Edit the text by double clicking
• Edit the Font Size and Colour using the attributes inspector in utilities

• Compile and Run the app in a simulator
• We have our very first app! :smile:

But nothing happens when we click the button :cry:

Connect the button to from the UI to the controller by creating a method

• open up the Assistant editor to view the controller file alongside the storyboard
• select the button whilst holding the control key
• drag it into the ViewController class
  • Fill in all the information as found in the screenshot below:
• we have now connected our very first UI item to the controller by creating a method! :smile:

Create your layout for the calculator

Now print the digit that you are selecting

HINT

• By selecting the option button and hovering over method names/arguments you'll see a little question mark ❓ (try this by hovering over the UIButton text)
• When you select the given text, it will open up a popup
• selecting the Class Reference link will open up the API Documentation which can be pretty handy when we are trying to find out the method for accessing the title for the digit.
  HINT

What the hell is Optional?

• Optional is a Type
• Can only have two values
  1. nil
  2. set
• When in the set state, it has an associated value. usually shown as such

String? //Where this is an optional with the associated value being a string

So how do we get the associated value? By Simple putting an exclamation mark at the end.

let digit = sender.currentTitle!

The console is now logging the correct digit that is being clicked by the user.

Add a Display to the UI

• select a label from the interface (drag & drop)
• link the label to the controller as an outlet

Get rid of the trailing zero

• set a global variable called userIsTyping and set it to false
• modify the currentTextInDisplay with an if statement

HINT

• All properties need to have an initial value
  HINT

Create our first Operation Key

• create a new button and change the title to π (pi)
• link the button to the controller as an action
• On click of the π button display pi. (Swift comes with mathematical methods, pi being one of them)

You've built your first ever kind of functioning calculator using swift on iOS! 🎉

[sohilpandya]

This Excercise has taken me 6 Pomodoro's instead of 4. So the task has taken me an hour longer than I expected.

Reasons

• Tried to document each step at the beginning and that was really time-consuming. (not sure if it really adds value either 😞

I am not happy with the above as it is quite a lot, It should be a lot more condensed than this. What do you think? @nelsonic

Review

• Really recommend this set of lectures, probably worth spending time doing 2-4 lectures each week.
• Might be worth doing loose documentation around it. (by loose, I mean not as detailed, but still cover the major points)