For anyone who’s developed exclusively with UIViews on iOS may take the title of this post a bit oddly. “WHAT?!” they might say, “Are you insane? Core Graphics is not only a C-only API, but has confusing function names, and needs way more code to do the same thing I can do in less code in UIView”. Yes, they might be right, but there’s a reason why Core Graphics exists. It’s FAST!
But using Core Graphics doesn’t mean that your code has to be confusing, or that you have to compromise flexibility for performance. You can have your cake and eat it too (aka you can have high-performing code that is easy to read). Read on to see what I mean.
Continue reading “Core Graphics isn’t scary, honest!”
As developers we spend most of our lives dealing with broken and barely-functional software: our own software. We do our best to make the applications we develop somewhat less broken and try to add features to make it functional. And once we finally get our software working bug-free and functioning stably, what do we do? Do we bask in the joy of a stable app and spend countless hours enjoying that moment? No, we move on to v1.1 or v2.0, adding more features and consequently more bugs. It’s kind of sad if you think about it.
Since much of our lives are spent with applications in various states of brokenness, understanding how to debug our software and catch those exceptions that arise is vital to getting our applications to a stable state so we can release, consequently moving on to create a whole new set of bugs that need to be fixed.
Here are some basic tips and tricks to make your life easier dealing with Xcode 4, and tracking down those places where your code runs off into the bushes.
Continue reading “Back To Basics: Simple debugging tips in Xcode”
One of my pet peeves is Open Source iOS libraries distributed as just a collection of Objective-C classes, rather than being bundled as a static library. I know a lot of people prefer it that way, but from a maintainability standpoint it really doesn’t make much sense to me. So when I’m faced with another library I want to use that doesn’t have a static library readily available for it, I typically wrap it up in my own Xcode project, check it in to Github, and configure my Jenkins continuous integration build server to compile it for me.
I thought I’d walk you through the steps I go through to make this happen, so you can use this technique too. Continue reading “Building a static library with Jenkins”
With iOS 4.0 Apple introduced two new technologies to the iOS platform: Grand Central Dispatch, and blocks. Simply put, it is to multi-threaded programming what fire is to a barbecue. Sure you can do without it, but the end result is much better.
Despite all this, developers still seem to avoid using it. Some of the reasons for this, off the top of my head, could be backwards-compatibility for older versions of iOS, unfamiliarity with the funky syntax it uses, or simply a lack of practice. The biggest thing I find however is a general misunderstanding about the importance of multi-threading among new developers, which was made worse by the difficulty of dealing with threads before blocks and GCD was released.
Fortunately there’s no reason to avoid multi-threaded programming in iOS, but before I dive into the specifics I’d like to point out just how important it is to use an asynchronous approach to development on iOS, or any mobile platform in general.
Continue reading “Using GCD and Blocks Effectively”
One of the things I like most about Apple’s iOS SDK is the consistent and easy-to-use API they provide. Across all their different frameworks there’s a pattern at work that makes using their classes easy to understand. This is due in part to the simplicity for configuring those objects. In most cases you don’t need to call cryptic methods to setup or teardown classes. If you want to change a label’s font, you just set a property. If you want to add a new set of tabs to a UITabBarController, you simply have to assign an array of view controllers to the “viewControllers” property and away you go.
Continue reading “Back to Basics: Using KVO”
Following up on my previous post in this series, I’m going to continue talking about beginner topics that I and many other developers take for granted. So for this entry in my “Back To Basics” series I’d like to talk about UITableViews, and how to simply and easily construct one without convoluted or confusing code.
This topic in particular is something I’ve struggled over in the past and never managed to find a clear example for how to get started. Certainly there’s a lot of examples to show how to construct a table view, how to create a datasource for it, and the basics for how to construct cells. But hardly anyone tells you how to easily and conveniently construct a menu of options without going down a maze of twisty passages.
So today I’ll show you how you can use simple “typedef” structures to describe and control a simple menu of options.
These days I’ve been working on some fairly advanced iOS development techniques on my various projects: I’ve taught myself (badly) about Core Audio, I’m learning OpenGL, I’m developing a series of applications using Core Data, asynchronous parsing of JSON from a streaming HTTP connection, etc. It’s extremely fun and easy once you understand the basics.
What I tend to forget however is that you have to crawl before you can walk, and many people still struggle with some of the simpler techniques that I’ve learned that may not be so obvious, even when reading books or tutorials on Objective-C programming.
Since my previous series of articles on Core Animation (Part 1, Part 2, Part 3, Part 4) were so well received, I thought I’d do another series of articles titled “Back To Basics”.
So without further ado, I give you the first part in my series: Positioning UIViews.