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

Getting Data from the Internet

If you want to retrieve data from the Internet and process it programmatically, rather than just display it in a view, you should use the NSURLConnection class. While it’s more complicated than the UIWebView we looked at earlier in the chapter, it’s inherently more flexible.

The NSURLConnection class can make both synchronous and asynchronous requests to download the contents of a URL, and the associated delegate methods provide feedback and control for asynchronous requests.

Synchronous Requests

The easiest, but not the best, way to use the NSURLConnection class is to make a synchronous request for data:

NSString *url = @"";
NSURLRequest *request =
   [NSURLRequest requestWithURL:[NSURL URLWithString:url]];

NSURLResponse *response = nil;
NSError *error = nil;
NSData *content = [NSURLConnection sendSynchronousRequest:request
  returningResponse:&response error:&error];

NSString *string = [[NSString alloc] initWithData:content
NSLog(@"response: %@", string);

sendSynchronousRequest: is a convenience method built on top of the asynchronous request code. It’s important to note that if you use this method the calling thread will block until the data is loaded or the request times out. If the calling thread is the main thread of your application, your application will freeze while the request is being made. This is generally considered not a good thing from a UI perspective; I strongly encourage you to use the asynchronous ...

The best content for your career. Discover unlimited learning on demand for around $1/day.