objc[<pid>]:FREED(id): message release sent to freed object="<memory_address>"

Double Release Of Cocoa Objects

After searching through my code, I couldn’t figure out where I was doubly releasing the object. Googling up, I found an article which helped introduce me to a few really good environment variables I could set that would allow me to identify where I was creating this problem. Here are the environment variables:

• NSZombieEnabled
• MallocStackLogging

With these two environment variables are set to “YES” in your executable’s Arguments tab, you then have the ability to figure out where you’re doubly releasing an object’s memory using in gdb:

shell malloc_history <pid> <memory_address>

(Note: To set these environment variables, double-click the executable in Xcode’s Executable’s group, click the Arguments tab and then add the variables.) And there you have it.)

Flash CS5: Native iPhone Application Development

The new support for iPhone applications in the Flash Platform tooling will not allow iPhone users to browse web content built with Flash technology on iPhone, but it may allow developers to repackage existing web content as applications for iPhone if they choose to do so.Flash Player uses a just-in-time compiler and virtual machine within a browser plug-in to play back content on websites. Those technologies are not allowed on the iPhone at this time, so a Flash Player for iPhone is not being made available today. Flash Professional CS5 will enable developers to build applications for iPhone that are installed as native applications. Users will be able to access the apps after downloading them from Apple’s App Store and installing them on iPhone or iPod touch. Developers can deliver applications built with Flash Platform tooling just like any other iPhone application. This will require the developer to be a member of the iPhone Developer Program and follow the program guidelines. iPhone applications built with Flash Platform tools are compiled into standard, native iPhone executables, just like any other iPhone applicatio. Applications can be built targeting iPhone OS 3.0 and later.

Update: Apple has bowled out Adobe’s effort to get iPhone application development on Flash platform with introduction of new clause in its iPhone SDK 4.0 license agreement which makes developing iPhone application using tools other than from Apple as illegal. Check more details about whats new in iPhone SDK 4.0 and its implications at http://www.macoscoders.com/2010/04/09/new-features-in-iphone-os-4-0/

According to Apple, the service will preserve battery life and maintain performance, not to mention work over WiFi or cellular. Look for it to roll out in September, with seeding to developers starting next month.

Push notifications —also known as remote notifications—let users learn when applications on their iPhone  and iPod Touch devices have data waiting for them on their servers. When a device receives a notification for an application ,it notifies the user through an alert message, a distinctive sound, or a number badging the application(or some combination of these). The user may then launch the
application, which then downloads the data from its server, which is also known as its provider. Introduced  in iPhoneOS3.0, push notifications serve the same purpose that a background application would on a  desktop computer.(As you may know,background applications are not allowed on these hand held devices.)

http://code.google.com/p/iphone-sdk-programming-book-code-samples/

I have pasted the extract of it here for a quick reference…

iPhone SDK

iPhone SDK Programming: Developing Mobile Applications for Apple iPhone and iPod touch, Maher Ali.

Paperback: 416 pages Publisher: John Wiley & Sons (March 30, 2009) Language: English ISBN-10: 0470742828 ISBN-13: 978-0470742822

Product Description With iPhone SDK Programming, developers have the expert guidance they need to begin building native applications for Apple’s new iPhone 3G as well as the iPod touch. Inside, veteran mobile developer and Bell Labs scientist Maher Ali begins with a foundational introduction to Objective C and Cocoa programming, and then guides readers through the building programs with Apple’s iPhone SDK.

iPhone SDK Programming covers a wide range of topics, including:

• The Objective-C programming language
• Collections
• Cocoa Touch
• Building advanced mobile user interfaces
• Core Animation and Quartz 2D
• Model-View-Controller (MVC) designs
• Table Views
• File management
• Parsing XML documents using SAX and DOM
• Working with Google Maps API
• Consuming REST Web Services
• Building advanced location-based applications
• Developing database applications using the SQLite engine
• Building Multimedia applications
• Making use of the camera and video
• Working with the accelerometer

TOC: Preface

1 Objective-C and Cocoa

1.1 Classes

1.2 Memory Management

1.3 Protocols

1.4 Properties

1.5 Categories

1.6 Posing

1.7 Exceptions and errors

1.8 Key-Value Coding (KVC)

1.9 Multithreading

1.10 Summary

References

2 Collections

2.1 Arrays

2.2 Sets

2.3 Dictionaries

2.4 Summary

References

3 Anatomy of an iPhone Application

3.1 Hello World Application

3.2 Building the Hello World Application

4 The View

4.1 View Geometry

4.2 The View Hierarchy

4.3 The Multi-Touch Interface

4.4 Animation

4.5 Drawing

5 Controls

5.1 The Foundation of All Controls

5.2 UITextField

5.3 Sliders

5.4 Switches

5.5 Buttons

5.6 Segmented Controls

5.7 Page Controls

5.8 Date Pickers

5.9 Summary

6 View Controllers

6.1 The Simplest View Controller

6.2 Radio Interfaces

6.3 Navigation Controllers

6.4 Modal View Controllers

6.5 Summary

7 Special-Purpose Views

7.1 Picker View

7.2 Progress Views

7.3 Text View

7.4 Alert View

7.5 Action Sheet

7.6 Web View

8 Table View

8.1 Overview

8.2 The Simplest Table View Application

8.3 A Table View With Both Images and Text

8.4 A Table View With Sections Headers and Footers

8.5 A Table View With The Ability to Delete Rows

8.6 A Table View With The Ability to Insert Rows

8.7 Reordering Table Rows

8.8 Presenting Hierarchical Information

8.9 Grouped Table Views

8.10 Indexed Table Views

8.11 Summary

9 File Management

9.1 The Home Directory

9.2 Enumerating A Directory

9.3 Creating and Deleting a Directory

9.4 Creating Files

9.5 Retrieving and Changing Attributes

9.6 Working With Resources and Low-Level File Access

9.7 Summary

10 Working with Databases

10.1 Basic Database Operations

10.2 Processing Row Results

10.3 Prepared Statements

10.4 User-Defined Functions

10.5 Storing Blobs

10.6 Retrieving Blobs

10.7 Summary

References

11 XML Processing

11.1 XML and RSS

11.2 Document Object Model (DOM)

11.3 Simple API for XML (SAX)

11.4 An RSS Reader Application

11.5 Summary

References

12 Location Awareness

12.1 The Core Location Framework

12.2 A Simple Location-Aware Application

12.3 Google Maps API

12.4 A Tracking Application With Maps

12.5 Working With ZIP Codes

12.6 Summary

References

13 Working with Devices

13.1 Working with the Accelerometer

13.2 Audio

13.3 Video

13.4 Device Information

13.5 Taking and Selecting Pictures

13.6 Summary

A Saving and Restoring App State

B Invoking External Applications

Pick a letter, any letter: The iPhone’s onscreen keyboard takes some getting used to, but it’s also incredibly versatile, supporting more than 20 different languages. Sometimes you don’t need a whole different alphabet, though—maybe you just need to be able to spell François or Mötley Crue. No worries, the iPhone’s got you covered: to insert one of those special characters, just hold down the base letter for a couple seconds (for example, to get ö, hold down the ‘o’ key) and you’ll see a menu of special characters pop up. Slide your finger to the right one, let go, and presto, you’re all set. Bonus tip: this technique also works with the “.com” key that you see when typing in a web address in Safari—hold it down and you’ll get options for .org, .net, and .edu too.

2.

There’s no place like home: The Home button is one of the iPhone’s few physical buttons; it’s also your best friend, because it’s always there for you. Clicking it will quickly jump you back to the home screen, whether you’re in an app or paging through your sixth screen of iPhone applications. If you visit Settings -> General -> Home Button, you can choose to have a double-click of the button bring up the Favorites screen of your Contacts, or pop up a dialog box with iPod controls. And if you’re trapped in a frozen or hung application, you can often escape by holding down the Home button for around six seconds.

3.

Take a picture, it’ll last longer: Maybe there’s some information on your iPhone you want to be able to retrieve later, like flight information, or perhaps you want to share that data with somebody else. Some programs, like Safari, let you email information to others, but many don’t. There is a workaround, though: take a screenshot. If you push the iPhone’s Home button and Sleep/Wake button simultaneously, the screen will flash to white and a screenshot of whatever you’re looking at will appear in your iPhone’s Photos app. From there you can attach the image to an e-mail message or just save it for future reference.

4.

Shake it up, baby: You’re going to spend a lot of time on the iPhone’s home screen, so just like your actual home, you’ll probably want to arrange it to your liking. By tapping and holding any application icon on the home screen, all the icons will jiggle like they’ve caught a bad case of dance fever. In this mode, you can drag-and-drop icons wherever you like; if you drag them to the edge of the screen, you’ll shift to the adjacent page. You can even drag icons in and out of the iPhone’s dock, if you want to have quick access to an application no matter what home screen you’re on. While the icons are shaking, you can also remove any third-party apps (those that don’t come with the iPhone) by tapping the little ‘x’ that appears in the top left corner. When you’ve got everything set up just the way you want it, tap the Home button to lock it in.

5.

The tip that keeps on tipping: That third-party application you downloaded would be great if only it just let you change that one little setting that’s driving you nuts, but you can’t find a preferences option anywhere in the program. That’s because Apple’s developer documentation asks programmers, rather unintuitively, to put their applications’ settings in the iPhone’s Settings app. Not all developers do Apple’s bidding, but it’s a good idea to check the Settings app before complaining to the program’s creator that something’s totally impossible.

And there you have it: a quintet of handy, helpful hints for the newest members of the iPhone club. Got a must-have iPhone tip to share with your fellow users? Deposit it in the comments below, for the good of all humanity.

Judging by checks with Apple suppliers, it appears the Cupertino, Calif., computer maker may be getting ready to introduce “a lower-cost version” of the popular iPhone.

Some call this device the iPhone nano.”, ” Whatever one calls it, we believe this device is on its way.”

“a new and smaller version of the iPod shuffle,” possibly in the middle of the first quarter and a cheaper MacBook notebook, although, “We do not believe this PC will qualify as a netbook.”

Don’t expect the products to be ready in time for a rollout at the upcoming MacWorld expo next week.

Officials at Apple could not immediately be reached for comment.