Cocoa Is My Girlfriend

An interesting question came up on Stackoverflow today so I decided to expound upon it in a short blog post.

A situation that I believe we are going to be seeing more and more often is one where application developers are writing multiple “versions” of their applications to be used on the desktop, their iPhone and now the iPad.

Because of that situation, it is becoming even more important that we write as much portable code as possible. Fortunately, our model can be completely portable between the two platforms.

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Everything is moving toward the cloud and unless you’re building calculators, unit converters, or miniature golf score keepers your iPhone app needs to know how to get data from it. In this blog post I intend to demonstrate how to set up a simple server application and how to retrieve data from it and post data to it using Cocoa Touch. I have chosen to use PHP on the server side because of it’s simplicity and ubiquity, and because I’ve know it, somewhat. You should, however, be able to implement something similar using your server side language of choice.

In many cases when you go to access remote data, you do so through a web service API. While services based on such technologies as SOAP or XML-RPC are standards that provide reasonable methods for retrieving and updating data, REST seems to be the methodology gaining the most ground lately. For our purpose in this post I won’t get into great detail of how to implement a REST base web service as, again, REST is not a specific implementation but rather a methodology. (Read up on it elsewhere if you don’t understand what this means). However, I will talk about it briefly so that you can get on the right path for doing your own REST implementation. Read more

I had to post a link to this one as well as Fraser does such a great job explaining why the iPad is so compelling . From Fraser’s post:

The tech industry will be in paroxysms of future shock for some time to come. Many will cling to their January-26th notions of what it takes to get “real work” done; cling to the idea that the computer-based part of it is the “real work.”

It’s not. The Real Work is not formatting the margins, installing the printer driver, uploading the document, finishing the PowerPoint slides, running the software update or reinstalling the OS.

The Real Work is teaching the child, healing the patient, selling the house, logging the road defects, fixing the car at the roadside, capturing the table’s order, designing the house and organizing the party.

Exactly! The iPad is genius and it will revolutionize not just books, magazines, etc., but it will revolutionize computing as we know it. I don’t know about you, but I’ve got the new SDK fired up and ready to start rocking some apps and it is a very exciting new platform!

Upon first glance, the UIButton class doesn’t seem to provide what you might expect in terms of customization. This often causes developers to resort to creating buttons in an image editor and then specifying that in the Background field in Interface Builder. This is a fine solution and will likely give you what you need, but with Core Animation layers there is a simpler way to achieve the look you want without having to create an image. This post will demonstrate how. Read more

Last month I was given the opportunity to write an article for The Pragmatic Programmers great magazine called “PragPub”. I am happy to say that the article I wrote for them was published in this month’s edition. The article, titled “Touching the Core”, is a walk through Apple’s great addition to the Core Data API for the iPhone.

Specifically this article walks through using the NSFetchedResultsController and some best practices in its use. The magazine is available for free on their website, The Pragmatic Bookshelf.

For those not aware, when you compile an Objective-C application, whether it be for the desktop or for Cocoa Touch devices, the debugging symbols are stripped out of the binaries. Therefore, unlike other languages such as Java, when a crash occurs, there is virtually no way to determine where the crash occurred. However, when the applications are compiled, a dSYM bundle is generated. This bundle allows us to match up the debugging symbols with the application’s crash log to help determine the cause of the crash.

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Our Core Animation book should be available by the end of the year. Go ahead and pre-order it now at Amazon if you would like ;-). When we started writing for Addison-Wesley back in September of 2008, I had no idea how long to expect it to take to finish a technical book as this was my first. One thing I discovered though, is that it is when you are about ready to go to production you start to realize all of the things that you probably should have added to the book, but didn’t think of in time. This blog post will cover one such item as a way to make up for not thinking of it in time. I may include this in a second edition if there is one, but consider this one a freebie. Read more

At first glance setting a height dynamically for table view cells seems a little daunting and the first most obvious answers that come to mind are not necessarily correct. In this post I will show you how to set your table view cell heights dynamically based upon the text content without subclassing UITableViewCell. You can subclass it, however, doing so does not make the code much cleaner as setting the height is done in your delegate for the table view itself rather than the cell anyhow. Read on to see what you need to know to make dynamic cell height sizing a breeze. Read more

I’ve seen a good bit of sample code that shows how to implement using a UINavigationController in a view controller that is managed by a UITabBarController, but I haven’t seen much on how to do it with Interface Builder. Turns out that it’s pretty simple and I’m going to show you how. Read more

Update: This is documented behavior.

Every now and again while doing development you stumble upon something that makes you go, hmmmm. Those are normally the moments at which you have to ask yourself, “is this a bug or a feature”. If it’s a bug, then you should file a radar with Apple, however, what if it’s a feature? You blog about it, of course!

I have done a bit less iPhone development than Marcus, so he was a little stumped while looking through some of my code where I created a view controller using a simple alloc/init. Most interestingly is that fact that the app works. It loads the correct nib and displays the view just fine without any trouble. Notice I said alloc/init and not alloc/initWithNibName. How can this possibly work? How did my controller “know” which view to use? Read more

As you develop applications for the iPhone, you will likely use the project templates provided in Xcode. One such template, called “Tab Bar Application” helps you get a tab bar application set up quickly, but by default the application it generates only supports portrait mode for display. So how can you make the application also support landscape or even only support landscape? In this post we will address that question. Read more

Similar to one of my first blog posts on building a basic application for Mac OS X using xcode 3.0, I am going to explain for beginning iPhone/iPod Touch developers how to build the most basic Cocoa Touch application using Interface Builder and an application delegate in xcode 3.1. This tutorial post is really to provide a quick how-to. I won’t go into any depth explaining why things are done the way they are done, but this should help you get up and running with your first application pretty quickly so that you too can clog the App Store with useless superfluous apps (kidding… just kidding).

If you are a visual learner, it may be helpful to you to instead watch a video presentation of this tutorial. I’ve posted it on the site, but you’ll have to click the link to see my Cocoa Touch Video Tutorial. Read more