You are previewing Learning iPhone Programming.

Learning iPhone Programming

Cover of Learning iPhone Programming by Alasdair Allan Published by O'Reilly Media, Inc.
  1. Learning iPhone Programming
    1. SPECIAL OFFER: Upgrade this ebook with O’Reilly
    2. A Note Regarding Supplemental Files
    3. Preface
      1. Who Should Read This Book?
      2. What Should You Already Know?
      3. What Will You Learn?
      4. What’s in This Book?
      5. Conventions Used in This Book
      6. Using Code Examples
      7. How to Contact Us
      8. Safari® Books Online
      9. Acknowledgments
    4. 1. Why Go Native?
      1. The Pros and Cons
      2. The Release Cycle
      3. Build It and They Will Come
    5. 2. Becoming a Developer
      1. Registering As an iPhone Developer
      2. Enrolling in the iPhone Developer Program
      3. The Apple Developer Connection
      4. Installing the iPhone SDK
      5. Preparing Your iPhone or iPod touch
    6. 3. Your First iPhone App
      1. Objective-C Basics
      2. Creating a Project
    7. 4. Coding in Objective-C
      1. Declaring and Defining Classes
      2. Memory Management
      3. Fundamental iPhone Design Patterns
      4. Conclusion
    8. 5. Table-View-Based Applications
      1. Simplifying the Template Classes
      2. Creating a Table View
      3. Building a Model
      4. Connecting the Controller to the Model
      5. Adding Navigation Controls to the Application
      6. Adding a City View
      7. Edit Mode
    9. 6. Other View Controllers
      1. Utility Applications
      2. Tab Bar Applications
      3. Modal View Controllers
      4. The Image Picker View Controller
    10. 7. Connecting to the Network
      1. Detecting Network Status
      2. Embedding a Web Browser in Your App
      3. Sending Email
      4. Getting Data from the Internet
    11. 8. Handling Data
      1. Data Entry
      2. Parsing XML
      3. Parsing JSON
      4. Regular Expressions
      5. Storing Data
    12. 9. Distributing Your Application
      1. Adding Missing Features
      2. Building and Signing
      3. Submitting to the App Store
      4. Reasons for Rejection
    13. 10. Using Sensors
      1. Hardware Support
      2. Using the Camera
      3. The Core Location Framework
      4. Using the Accelerometer
      5. Using the Digital Compass
      6. Accessing the Proximity Sensor
      7. Using Vibration
    14. 11. Geolocation and Mapping
      1. User Location
      2. Annotating Maps
    15. 12. Integrating Your Application
      1. Application Preferences
      2. Custom URL Schemes
      3. Media Playback
      4. Using the Address Book
    16. 13. Other Native Platforms
      1. PhoneGap
      2. MonoTouch
    17. 14. Going Further
      1. Cocoa and Objective-C
      2. Web Applications
      3. Core Data
      4. Push Notifications
      5. In-App Purchase
      6. Core Animation
      7. Game Kit
      8. Writing Games
      9. Look and Feel
      10. Hardware Accessories
    18. Index
    19. About the Author
    20. Colophon
    21. SPECIAL OFFER: Upgrade this ebook with O’Reilly
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Chapter 8. Handling Data

Most applications on the iPhone platform will make a network connection to retrieve data at some point. This data will usually be formatted so that it can be easily parsed, either as XML or, more frequently these days, as JSON.

In this chapter, we’re going to look at how to get data directly from the user via the UI, and then how to parse data we’ve retrieved from the network. Finally, we’ll look at how to store that data on the device.

Data Entry

The Cocoa Touch framework offers a number of UI elements, ranging from text entry fields to switches and segmented controls. Any of these can be used for data entry, but often when we talk about data entry we’re talking about getting textual information into an application.

The two main UI elements that allow you to enter text are the UITextField and UITextView classes. While they may sound similar, they are actually quite different. The most noticeable difference between the two is that the UITextView allows you to enter (and display) a multiline text field, while UITextField doesn’t.

The most annoying difference between the two is the issue of the resigning first responder. When tapped, both display a keyboard to allow the user to enter text. However, while the UITextField class allows the user to dismiss the keyboard (at which time the text field resigns as first responder) when the user taps the Done button, the UITextView class does not. Though there are multiple ways around this problem, as we’ll find later on, ...

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