Friday, August 29, 2014 CSCI 351 – Mobile Applications Development

Developing Apps for IOS

The Basics What is an app? App is simply short for application. It is computer software written for a specific user task. What is IOS? Originally iPhone Operating System, IOS is a mobile operating system developed and distributed by Apple. It was released in 2007 for the iPhone and the iPod Touch. It was later extended for the iPad and Apple TV. Over 40% of smart phone subscribers use an Apple phone. Current market share for smart phones:

The Basics Americans used smartphone and tablet apps more than PCs to access the Internet in January, the first time that has ever happened. Mobile devices accounted for 55% of Internet usage in the United States in January. Apps made up 47% of Internet traffic and 8% of traffic came from mobile browsers. PCs clocked in at 45%.

The Basics What is Objective-C? It is a high-level, object-oriented programming language. It is the main language used for IOS and OS X application development. What is Swift? It is a multi-paradigm, compiled programming language developed by Apple for iOS and OS X development. Introduced in 2014, Swift is designed to work with Apple's Cocoa and Cocoa Touch frameworks and the large body of existing Objective-C code written for Apple products. Swift is intended to be more resilient against erroneous code. It is built with the LLVM compiler included in Xcode 6 beta, and uses the Objective-C runtime, allowing Objective-C, Objective-C++ and Swift code to run within a single program.

The Basics What is Cocoa Touch? It is the user interface (UI) framework for building IOS applications. It is based on Cocoa, which is the application programming interface (API) for the Mac operating system. What is Xcode? It is an integrated development environment (IDE) containing a suite of software development tools developed by Apple for developing software for OS X and iOS. First released in 2003, the latest stable release is version 5.1 and is available via the Mac App Store free of charge for Mac OS X Lion, OS X Mountain Lion and OS X Mavericks users. Registered developers can download preview releases and previous versions of the suite through the Apple Developer website. Apple recently made a beta version of version 6.x of the software available to those of the public with Apple Developer accounts.

Developing Mobile Apps Mobile apps are designed for smart phones, tablets, and other mobile devices. How is developing mobile apps different than traditional software development? The screen size is limited: First 3 generations of iPhone: 320x480 ppi (pixels per inch) iPhone 4 and iPhone 4s:640x960 ppi iPhone 5:640x1136 ppi The iPad and iPad2 have a screen resolution of 1024x768 Retina displays can double the resolution in both directions. Only one IOS application can be active and displayed on the screen at a given time. IOS applications have just one window to work with.

Developing Mobile Apps More differences between developing mobile apps and standard software IOS apps can read and write files in an area called a sandbox. There is limited access to the rest of the device. Programs need to open quickly and close down quickly. For example, If your app takes more than 5 seconds to give up control when the user hits the home button, the app may be killed. Conserving memory is important in writing apps. A device (i.e., iPhone 4s, iPad 2) may have 512MB of RAM, but much of that is used for the screen and by other system processes.

Developing Mobile Apps IOS devices have features that many Macs do not have: Determining geographic coordinates Built-in camera Built-in accelerometer To develop apps for IOS, you will need: A Macintosh computer Xcode software To register as an Apple Developer

Creating a simple “Hello World” app 1. Create a New Xcode Project 2. Choose IOS Application, Single View Application -> Next 3. Enter Hello World for the Product Name 4. Choose a location and then Create 5. Click on Main.Storyboard, the top of the View Controller, then Attributes (at the right). Change Size to iPhone 4-inch and Orientation as Portrait 6. From the Object Library at the bottom right, choose and drag both a label and a button to your View Controller 7. Close the Utilities window and click on the Assistant Editor Control-Drag the label to right below the line that starts Class View… Enter theLabel as its name Modify the line of code if needed so that it var theLabel: UILabel? (Note the question mark at the end.) 1. Control-Drag the button to below your outlet. When the popup occurs, choose Action as the Connection type and give it a Name of theButton 2. In the function that was created, add this line between the braces: theLabel?.hidden = true 1. Run your program using the simulator