Create First iPhone App

Your First iOS App introduces you to the Three T’s of iOS app development:

• Tools. How to use Xcode to create and manage a project.
• Technologies. How to create an app that responds to user input.
• Techniques. How to take advantage of some of the fundamental design patterns that underlie all iOS app development.

After you complete all the steps in this tutorial, you’ll have an app that looks something like this:

As you can see above, there are three main user interface elements in the app that you create:

• A text field (in which the user enters information)
• A label (in which the app displays information)
• A button (which causes the app to display information in the label)
  

When you run the finished app, you click inside the text field to reveal the system-provided keyboard. After you use the keyboard to type your name, you dismiss it (by clicking its Done key) and then you click the Hello button to see the string “Hello, Your Name!“ in the label between the text field and the button.

To benefit from this tutorial, it helps to have some familiarity with the basics of computer programming in general and with object-oriented programming and the Objective-C language in particular.

Note: You can use this tutorial to get started with iOS app development even if you intend to develop solely for iPad. Although this tutorial shows the iPhone user interface, the tools and techniques you use are exactly the same as those you use to develop iPad apps.

To create the iOS app in this tutorial, you need Xcode 4.3 or later. Xcode is Apple’s integrated development environment (or IDE) for both iOS and Mac OS X development. When you install Xcode on your Mac, you also get the iOS SDK, which includes the programming interfaces of the iOS platform.

Create and Test a New Project

To get started developing your app, you create a new Xcode project.

1.Open Xcode (by default it’s in /Applications).

If you’ve created or opened a project in Xcode before, you might see a project window instead of the Welcome to Xcode window.

2. In the Welcome to Xcode window, click “Create a new Xcode project” (or choose File > New > Project).

Xcode opens a new window and displays a dialog in which you can choose a template. Xcode includes several built-in app templates that you can use to develop common styles of iOS apps. For example, the Tabbed template creates an app that is similar to iTunes and the Master-Detail template creates an app that is similar to Mail.

3. In the iOS section at the left side of the dialog, select Application.

4. In the main area of the dialog, select Single View Application and then click Next.

A new dialog appears that prompts you to name your app and choose additional options for your project.

5. Fill in the Product Name, Company Identifier, and Class Prefix fields.

You can use the following values:

• Product Name: HelloWorld
• Company Identifier: Your company identifier, if you have one. If you don’t have a company identifier, you can use edu.self.
• Class Prefix: HelloWorld

1. 
   
   

   Note: Xcode uses the product name you entered to name your project and the app. Xcode uses the class prefix name to name the classes it creates for you. For example, Xcode automatically creates an app delegate class and names it HelloWorldAppDelegate. If you enter a different value for the class prefix, then the app delegate class is named YourClassPrefixNameAppDelegate. (You’ll learn more about the app delegate in “Find Out How an App Starts Up.”)

   To keep things simple, this tutorial assumes that you named your product HelloWorld and that you used HelloWorld for the class prefix value.

6. In the Device Family pop-up menu, make sure that iPhone is chosen.

7. Make sure that the Use Storyboards and Use Automatic Reference Counting options are selected and that the Include Unit Tests option is unselected.

8. Click Next.

Another dialog appears that allows you to specify where to save your project.

9. Specify a location for your project (leave the Source Control option unselected) and then click Create.

Xcode opens your new project in a window (called the work-space window), which should look similar to this:

Take a few moments to familiarize yourself with the workspace window that Xcode opens for you. You’ll use the buttons and areas identified in the window below throughout the rest of this tutorial.

If the utilities area in your workspace window is already open (as it is in the window shown above), you can close it for now because you won’t need it until later in the tutorial. The rightmost View button controls the utilities area; when the utilities area is visible, the button looks like this:

If necessary, click the rightmost View button to close the utilities area.

Even though you haven’t yet written any code, you can build your app and run it in the Simulator app that is included in Xcode. As its name implies, Simulator allows you to get an idea of how your app would look and behave if it were running on an iOS-based device.

To run your app in Simulator

1. Make sure that the Scheme pop-up menu in the Xcode toolbar has HelloWorld > iPhone 5.0 Simulator chosen.
   If the pop-up menu does not display that choice, open it and choose iPhone 5.0 Simulator from the menu.
2. Click the Run button in the Xcode toolbar (or choose Product > Run).
   Xcode displays messages about the build process in the activity viewer, which is in the middle of the toolbar.

After Xcode finishes building your project, Simulator should start automatically (you might have to wait a few seconds for Simulator to appear on top of the workspace window). Because you specified an iPhone product (rather than an iPad product), Simulator displays a window that looks like an iPhone. On the simulated iPhone screen, Simulator opens your app, which should look like this:

Source : developper.apple.com

Read more from : http://developer.apple.com/library/ios/#documentation/iphone/conceptual/iphone101/Articles/01_CreatingProject.html