Programming

LLVM Module Maps to the rescue!

I recently wrote about Cocoa / Cocoa Touch frameworks, and in writing about it I was sorely tempted to dive into Modules, since they are pretty important to modern frameworks. But it was such a huge topic, I decided to break it out into a separate post.

In a nutshell, LLVM Module Maps were invented as a way to improve how source code imports other frameworks.

If you’ve ever worked on traditional C/C++ software projects (Makefile, CMake, gcc…any of these ring a bell?) you’ll know that the more code you add, the longer it takes to build, and the more likely you are to have conflicting types or macro definitions.

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Cocoa Dynamic Frameworks

If you don’t know the nuts and bolts of how your code is compiled, linked, and executed on target devices, you aren’t alone. And lets be honest, this is perfectly fine! That’s the great thing about abstraction: not everyone need be an expert at everything in order to be effective.

There are times though where a little bit of knowledge can go a long way to help troubleshoot particularly onerous problems. So I thought I’d explain a bit about how apps work in Cocoa (and by extension, Cocoa Touch), particularly how frameworks work.

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Logging with CocoaLumberjack and TestFlight

Consider the following situation that happens far too often in mobile app development: You’ve just released an app that works perfectly for you, and you’ve tested it extensively. You’re proud of your accomplishments and submit the app to the world, only to have several emails sent to you from users who have nothing but difficulties in running the app. You send a bug fix release to the App Store, but since you’re still unable to reproduce the problem you’re at the whim of luck and end-user feedback. You can hope your users know how to send you a crash report, but what if the app isn’t actually crashing? Wouldn’t it be great to be able to access your app’s log information from that client to be able to troubleshoot the problems?
Read More »Logging with CocoaLumberjack and TestFlight

Docset Viewer v1.2 and how to customize iCloud backups

I’ve recently released version 1.2 of Docset Viewer, which fixes a number of bugs people experienced with the previous version. If you had problems with the previous release, please give this one a try.

One of the improvements I’ve added is the ability to customize whether or not you would like to back up your Docsets (which can get quite large) into iCloud. To keep with the instructional nature of this site, I’ll show you how you can do that in your own apps.
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Docset Viewer: Resuming large downloads with NSURLConnection

As I’ve shown in my previous post announcing Docset Viewer, I want this series of posts to be more than me talking about my new app. In keeping with the instructional nature of my site, I’m going to show you a few things that I did in my new app Docset Viewer and how I put it together. This time around I’m going to show how I use NSURLConnection for downloading large files, and even resuming them.

In Docset Viewer I’ve added the ability to download docsets directly from Atom feeds, either from custom URLs or from a pre-configured list of Apple’s available docsets. Since you may not be consistently connected to the Internet, it’s important to be able to download documentation packages incrementally, especially since they can be anywhere from 300MB to 500MB.Read More »Docset Viewer: Resuming large downloads with NSURLConnection

Core Graphics isn’t scary, honest!

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.
Read More »Core Graphics isn’t scary, honest!

Building a static library with Jenkins

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.Read More »Building a static library with Jenkins

Using GCD and Blocks Effectively

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.
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Back to Basics: Using KVO

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.
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Back to Basics: Simple UITableViews

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.

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