Diving Into ios Development

Presented by Matt Piccolella and ADI

Who is this Talk Meant for?

• Past Advanced Programming students (read: people who can program C)
• Android or web application developers who are familiar with the Model-View-Controller framework
• People interested in building awesome applications for iPhone and iPad (hopefully all of you!)

What you can expect to Learn

• The major files and components involved in building an iOS application
• How to use XCode and its ~amazing~ interface builder
• Where to find the things you need to continue to level up your iOS

What You cannot Expect to Learn

• Objective-C
  • It's a superset of C, so it's easy to learn if you know C
• All of iOS Development
  • An hour is incredibly short, learning iOS takes time

Structure of the Talk

• Big-picture concepts and code samples in the slides
• Live-coding of a simple quiz application to show the concepts and how to use XCode
• Do not code along!
  • Installation of XCode can be tricky
  • Highly commented code available on Github
  • Come to Cookies and Code after for help getting it set up on your computer!

Getting Started: New Project

• File -> New Project
• Select 'Single View Application'
• Select 'iPhone' for device

• Product Name is your app name
• Bundle identifier helps to uniquely identify your app
• Language is Objective-C but can also be ~Swift~

Things to Remember

Project Structure and Important Files

• AppDelegate.m and AppDelegate.h
  • Master
• ViewController.m and ViewController.h
  • Controller
• Main.storyboard and LaunchScreen.xib
  • View
• Supporting Files
  • Info.plist - information about the application (name, version number, etc.)
  • main.m - needed to run the C application, DON'T TOUCH THIS
• Tests! Write these!

A Pattern: Model-View-Controller

Idea: Split up the responsibilities of an application

• Model - an object representing data (think something that would be stored in a database)
• View - some kind of a visualization of the data (what you see on the screen
• Controller - handles interactions between the user and the view to change the state of the model

View: Main.storyboard

• Storyboard essentially allows us to place all the views of our application in a single file
• We place sub-views (text labels, buttons, etc.) inside of our view to define what the view will look like
• Think of it as a roadmap for our application - how each screen interacts with another

Navigator

Editor

Utility

Make sure 'Use Size Classes' is not checked!

Adding Views: Drag and Drop

Formatting Views: Properties Selector

• Format things like text size, color, alignment, etc., using the properties selector (the fourth option at the top of the utilities screen)
• Super simple! Just like you would format things in Microsoft Word, etc.

Controller: ViewController.M

• Now we've created our view with our text labels, text field, and buttons
• We need to be able to respond to button presses by changing the text of the labels, but how do we do this?
• Answer: OUTLETS
  • Outlets allow us to communicate with the views we've added and to intercept certain actions
• We add outlets to our ViewController by using assistant editor and dragging from our view to the code

Adding Outlets: Actions and Outlets

* For actions, the method signatures automatically get added! *

Model: QuizQuestion

• Let's create an Objective-C class for our model to encapsulate a QuizQuestion
• File -> New -> File -> Cocoa Touch Class
• Easy! Like normal programming with properties and constructors

Wiring it All Together: Controller

• We have all our outlets, let's write them together so our application works!
• In ViewController, use the viewDidLoad function to set the initial state of the view
• Use this method to instantiate instance variables and set the first user interface the user will see

Fill in your Actions: Respond to Button Presses

• In our Action outlet methods, we can define what happens when a button is pressed.
• In this case, we check whether a user's answer is correct and alert them, while also keeping track of their score.

One More Thing: First Responders

• Our application works! But we can't exit the text box
• We need to conform to the UITextFieldDelegate
  • Set of methods we need to define (i.e.Java interface)
• Make ViewController first responder for Text Field by dragging and dropping in interface

Running our App: AppDelegate

• AppDelegate is the master of our application, handling important events throughout its lifetime, involving the opening and closing of the application

Running our App: The Simulator

• It costs money to run on our phones :( but use the simulator!
• Choose either iPhone 5 or 5S (we didn't use Size Classes), press the play button, and play with your brand new app!

Next Steps

• Install XCode and download the code from today
  • http://github.com/mjp2220/SimpleQuizGame
• Check out "iOS Programming: The Big Nerd Ranch"
• Use the iOS Dev Center on Apple's website to learn more about fundamental concepts and the SDK for iOS
• Come to Cookies and Code for help installing XCode
• Check out the ADI resources page
  • http://adicu.com

Now Go Build Awesome Apps!