1. iOS - iPhone/iPad Application Development Workshop Part 1

2. What do you need?
Previous experience in another Object Oriented Programming (OOP) language will be helpful
Some understanding of C can be helpful, but is not required. Objective-C builds on C++.
Development Environment (IDE) is helpful
Mac computer running OS X Lion or higher!
If you plan to submit to the App Store, you will need Apple devices to do real testing on. The simulator is not good enough.

3. Introduction
iOS is the operating system that runs iPhones, iPod Touches, iPads, and Apple TVs.
The language used to develop software for iOS is Objective-C. (very similar to C)
This workshop will teach you how to get started but will not have time to teach you everything.
This workshop is good preparation for a real full iPhone/iPad, iOS Development class!

4. What is iOS? iOS is an OS. It’s a subset of Mac OS X.
The iOS SDK is the software development kit that allows application programs to utilize classes and frameworks provided by the SDK. This workshop will focus on iOS SDK 5
iOS is multitasking and runs on different devices (iPhones, iPod Touches, iPads, and Apple TVs).
Apple provides an IDE called Xcode.
Xcode is the IDE used by iOS (and OS X) developers. It does NOT run on MS Windows.
Xcode provides an interface to the compiler, editor, debugger, and code profiling tools.

5. Device Features SQLite for structured data storage
Media support for common audio, video, and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)
GSM Telephony (hardware dependent)
Bluetooth, EDGE, 3G, and WiFi (hardware dependent)
Camera, GPS, compass, and accelerometer (hardware dependent)
Rich development environment including a device simulator, tools for debugging, memory and performance profiling

6. Download the iOS SDK Download the latest from the Apple App store
This is only available for Apple Macintosh computers
It’s free
To build to device and submit to the app store, you will be required to becomes a register Apple iOS developer
It’s $99 year for the basic account
If you plan to get a job in iOS development, you will need to establish a basic account and submit something to the Apple Store. Maybe a game?

7. Let’s get started - Launch Xcode
You are presented with the Welcome screen:
Create a new project
Connect to a repository
Learn about using Xcode
Go to Apple’s Portal
Go ahead and click on “Create a new project”

8. Project Template
There are several predefined templates to help you get started on a new project
For now, click on Single View Application

9. Project Options The Product Name is the name of your app
Company Identifier is your organization name – such as edu.itu (reverse domain)
Class Prefix (leave empty)
Device Family: iPad, iPhone, Universal (Universal means that a single binary will have screens for iPhone, iPod Touch, and iPads)
Storyboards
Automatic Reference Counting
Include Unit Tests (leave unchecked as we are not using)

10. Source Control Asks for a location for Source Control
By Default, it will use a local GIT repository
New developers not used to source control – this is extremely useful!
It keeps track of versions, lets you see what’s changed, and will undoubtedly be used in any team project you run into in the “real” world
GIT and Subversion are two popular source controls systems – there are many others to choose from

11. Where do I start?

12. Let’s build the default project
Click the Run button (upper left of the screen)
The iPad simulator will launch (You can also change this to iPhone if you want)
You will have a blank white screen
Press Command-Q to end the simulator

13. Quick Terminology: MVC
Model-View-Controller (MVC)
MVC is the paradigm of iOS programming
Model: Holds data, should know nothing of the interface
View: Code for getting data in/out of a view. Deals with items like buttons, lists, tables, etc
Controller: Keeps the Model objects and View objects in sync

14. Quick Terminology: Delegate
AppDelegate.h
AppDelegate.m
The Delegate is essentially the “controller” of your app. It links buttons, labels and views together
.h files are header files and interfaces are defined here
.m files are implementation files. These contain your classes, code, etc.

15. Quick Terminology: Storyboard
These are new to iOS5
Storyboards help you graphically lay out your app before you code it.
It makes it easy to see the “flow” of your app
You are advised to use Storyboards going forward with you iOS programming adventures
If you have tinkered with iOS in the past, you might be asking about the xib/nibs. They are still there, however, Storyboards offer similar functionality and make it easier to visualize your views.
We will not be covering nibs in this workshop.

16. Quick Terminology: ARC
Automatic Reference Counting (ARC)
The LLVM 3.0 compiler handles memory management for you
It is not a garbage collector!
Prior to iOS5 – memory management was the single most difficult item to grasp in Objective-C.
Unless you have specific reasons, all of your projects should use ARC.

17. Quick Terminology: Unit Tests
We will not be discussing Unit Tests in this workshop
Be advised – unit tests are very useful for your programs
The tests can help you make sure your code changes are not breaking anything.
The goal is to be able to find bugs quicker and fix them before your code goes to QA (or the customer!)

18. Click on the iPhone Storyboard
It shows a blank view
It looks like you are on a sheet of graph paper
There are two buttons – below
First Responder
View Controller

19. Find the Label
In Xcode, lower right hand corner, scroll until you find the object Label
Drag Label to the blank view
Double click on the Label you added, and change it to say “Hello World”
Do the same steps for the iPad Storyboard

20. Run the project
The iPad and iPhone projects should now display Hello World!

21. Next, add two buttons to your view
Find the Round Rect Button, drag two to the view
Double-click on one of the buttons and type Hello
Double-click on one of the buttons and type Goodbye
Run your project, click on the buttons

22. Nothing Happens – we have to tell it to do something
Click on the Assistant Editor
It looks like a tuxedo
It will be in the upper right hand corner of your screen

23. Linking the ViewObject to your ViewController…
You will see your ViewObject in the middle of the screen
The right hand side of the screen should be the ViewController.h file
View Object
ViewController.h

24. Link the label… Single click on your Hello World label
While holding down the Control key, left click-drag to the ViewController.h file
You need to drag between in the code
This will make a new property
For the name, call it helloLabel so we can easily recognize what it is
This step will allow us to make changes to the UILabel

25. @interface
Remember that Objective-C is an extensive to the C language
symbol denotes an Objective-C keyword
@interface is the start of a class.
@interface Classname: Superclass
Anything between the declaration and end is part of the class

26. @property (weak, nonatomic) IBOutlet UILabel *helloLabel;
A property is an attribute of the class
Getters and Setters are automatically created for you
Weak is a memory management term
Nonatomic has to do with adding mutexes around your getters and setters
IBOutlet stands for Interface Builder Outlet.
Interface Builder still exists in iOS5 but we are using the new Storyboard feature instead.

27. @synthesize helloLabel
Synthesize – this creates the accessor/mutators (getters/setters) for you
You can write your own if you want, but in general, there is no reason to do this.

28. Link the rest of the buttons
Link helloButton to ViewController.h
Link goodbyeButton to ViewController.h
When done, you will have two properties
Now, switch the Assistant window to the ViewController.m file

29. TouchUpInside Actions
TouchUpInside events occur if you touch a button and lift off while inside the button This corresponds to a user tapping a button Right-Click on the Hello button On the far right, locate Touch Up Inside Left click-drag this over to your ViewController.m Notice it creates some code Do the same for the goodbye button

30. IBAction You created two IBActions
Actions signify something that happens when you do something for example, push a button.
When you push a button, it fires the action
These are currently empty methods
- (IBAction)helloPushed:(id)sender { }
- (IBAction)goodbyePushed:(id)sender {

31. Change the UILabel - (IBAction)helloPushed:(id)sender {
Pushed"; }
- (IBAction)goodbyePushed:(id)sender {
Pushed";
Self refers to the ViewController class
We defined the property helloLabel earlier
Text is a property of UILabel’s that we can set.
text” is an NSString object that UILabels can display.
Run your program and push the buttons. You should see the UILabel change when you press the buttons

32. Tab Controller
If you’ve ever used an iOS device, you have come across apps that use the tab controller.
Several of the built in apps (such as the phone app) use this controller
For the next exercise, we are going to create a simple tab controller

33. Create a new project
Close any existing projects you have open (to make things easier!)
Select File->New->Project from the application menu

34. Select Tab Template
Select the “Tabbed Application” Template for your project

35. Set Options For product name, call it tabDemo
Whatever you used for Company Identifier should be set – if not, edu.itu is ok
Leave Class Prefix blank
For Device family, choose iPhone (to keep it simple)
Enable Storyboards and Arc
Do not select Unit Tests

36. Look at the Storyboard Click on MainStoryboard.Storyboard
Notice how the Tab Bar Controller is shown
It also shows the child views associated with the tab bar buttons
This lets the developer see the views and path to them at a quick glance.
Go ahead and run the project, observe what happens when you tap the tab items. It switches between the views

37. Let’s add a new class: ThirdViewController
On the left hand side, right-click on the tabDemo folder and select New File

38. Pick the type of file
We are adding a new ViewController – so select Objective-C class

39. Pick the options For Class, type in Third
In the Sublass combo box, select UIViewController
The IDE will change your class name
It is good naming convention to have the class be description – so in this case, ThirdViewController lets any developer know this is a ViewController
Leave Targeted for iPad and XIB unchecked

40. Create
Take the default options, click the Create button

41. We now have a .h and .m Notice that you now have two files
ThirdViewController.h and ThirdViewController.m
If you look at the files, they are basically “skeleton” classes ready for the developer

42. Add another View Controller
Add a new View Controller to the Storyboard
After you add it, it will not be linked to any view

43. Our new view, all alone
Notice that Storyboard does not have any arrows pointing to it
The developer will have to make the association as this view could be a sub view of any of the views shown

44. Link this ViewController to the Tab Controller
Hold down the Control key, left-click drag from the Tab Controller to the new view we just added
This tells Storyboard that this view is going to be accessed from the tab controller

45. Select Relationship

46. Label this before we forget
Click on the Text
Change this to say Third
We do not have any graphics – if we did, we would want to go ahead and add a graphic for this.
Note: you will need graphics for standard iPhones, retina, and iPads.

47. Lets be more specific about the class
Left Click on your new view in Storyboard – icon on right bottom
Click the Identify Inspector (upper right)
Notice how the class is currently UIViewController
We need to make this to be associated with our ThirdViewController (which is a subclass of UIViewController)

48. Select ThirdViewController
From the combo box, scroll until you find ThirdViewController
This will let us do any custom actions we might need to do
Remember: ThirdViewController has all of the methods and properties of a UIViewController!

49. Let’s Replace the First View
We are going to replace the FirstViewController with a TableViewController
Click on First View, hit the Delete button to remove it

50. Drag a Table View Controller
From the Object Library, drag over a Table View Controller
A good spot would be where you just deleted the other view controller

51. Embed Navigation Controller
From the Xcode menu bar, select Editor->Embed In->Navigation Controller
Notice that another view controller is added to the Storyboard canvas

52. Check it out This is what we did in the previous slide
Since the Navigation Controller is a container, there is a relationship between the Navigation controller and the table view controller. (Noted by the connecting arrow)

53. Hook up the Scenes
Ctrl-drag from the Tab Bar controller to the Navigation controller
Select Relationship – View Controllers

54. Look at Storyboard now The relationship is defined
When we added this, it added an entry labeled “Item” as the last tab bar button
Drag this “Item” and make it the first entry in our tab bar

55. Fix up the tab bar items Drag item to the left most position
Also, let’s rename this back to First
Double-click on Item in the Navigation Controller scene, change text to First

56. Name the Navigation bar
In the Table View window, double-click on the Title bar.
Type in “Things” to give the Navigation bar a name.
In a “real” app, you would type something descriptive and meaningful to the user.

57. The Navigation Bar has a title
You can now see the title has a name.
If you have noticed, we have been getting a warning from the compiler for our storyboard.
“Prototype table cells must have reuse identifiers”

58. Let’s get rid of the warning
Warnings are typically not something you want in your program.
We are getting this warning because we have not configured the cells yet – so the compiler does not know what they are.

59. Table View Controller Click on the blank prototype cell
Next, click on the attributes inspector and set Style to Subtitle.

60. Attributes Inspector

61. More cell attributes
Set the Accessory attribute to Disclosure Indicator.
Give the cell an identifier of ThingsCell.
The warning from Xcode is a reminder to developers – there is something you need to do if you want this to work.
(Side note – warnings are something you should not overlook. Several program crashes can stem from warnings people don’t pay attention to.)

62. Add a UIViewController subclass template…
Add a new file to the project.
Choose UIViewController subclass template.
Name the class ThingsViewController, this will be a subclass of UITableViewController

63. New file

64. Objective-C Class

65. ThingsViewController

66. Create to add to project

67. Set the class with Identify Inspector
Click on the TableViewController object (the whole object will be outlined in blue)
Now, click class and select ThingsViewController

68. Build and run! Go ahead and build the app
You can now add items to the table view if you want to continue working with this app.

69. HelloTabBar Example Download: http://bhecker.com/ip-HelloTabBar.zip
Save to your desktop.
Double-click to uncompress the file
Double-click on “HelloTabBar.xcode.proj” to load the project in XCode
Examine and customize as you wish!

70. The End of Part 1 Next… Part 2 Objective-C Programming