iPhone First "Hello World" app

see previous article on system requirements

creates simple application with "dummy" interface meaning no event handling

Step 1: Creating a simple iPhone Application

• this application will be for iPhone only (you can choose to create application for both iPhone and iPad or only one type of device).
• Will have a simple "View" interface that only says Hello.
• No event Handling

1. Launch your XCode tool
2. File->New Project -> iOS -> Window-based Application (OR whatever kind of applciation you want). Select the device you are targeting (iPhone in our case)
3. You will get a default directory structure as described on the iOS Xcode Project Structure page.
   
   
   
   
   
   

Step 2: Create a simple "Hello World" Interface

• Interfaces are represented in iPhone world using xib files (xml files proprietary to apple) that contain components (View objects)
• Uses Interface Builder -a main part of Xcode to build the interface

1. Launch Interface Builder by double clicking on the the interface file MainWindow.xib or may be called HelloWorldViewController.xib file if you created a View type applciation. This represents the single current interface for this application
   
   Interface Builder has multiple windows:
   
   
• Doc Window = represents the XIB file
• 
  • File's Owner = instanace of UIApplication = event queue for your applcation
  • First Responder = ignore fo rnow (relic from desktop cocoa)
  • HelloLynneDelegate = subclass of NSObject created by Xcode for this project. This is how iOS includes the Delegate pattern in development.
  • View = represents this applciations main interface
    
    
    NOTE: you can depending on the type of applcation you created (here View-based Application, or Window-based Application have a different elements in the Doc Window...for example Window will be the element associated with instance of UIWindow for a Window-based Application project)
    
    
• Library = contians list for drag and drop of View components --buttons, labels, text fields, etc.
  
  
  
  
  
• Inspector = where you can set attributes of your View components, Setup Connections ( between components and their data/model representation....MVC framework) and also Size and Info about how the application interacts.
  Note that we have at the top
• tabs for Attributes, Connections, Size and Info
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
• Instance of View/Window = this is the actual interface you drag components to. Here it is initally blank.
  
  
  
  
  
  
2. Drag and drop elements from the Libraries list of View elements to the interface you are building. Here we have dragged a Label and a button. In the Inspector Window I also set it up so the Label was centered.
   
   
   
   
   
   
3. Save your file

Step 3: Run the Project in your Simulator

• Hit the Build and Run Button
• Here is an example of the "Dummy" application with no event handling that pops up in the simulator