Articles about Swift, Cocoa, software design and programming.
This week I present some further additions to AudioStreamer, a class I first presented in Streaming and playing an MP3 stream and revisited with bug fixes in Revisiting an old post: Streaming and playing an MP3 stream. This time, I'll add the two of the most requested features: seeking and HE-AAC audio support.
In the "modern" Objective-C runtime (that's iPhone OS or 64-bit Mac OS X), you can dynamically add ivars (instance variables) to a class without declaring them first. This allows a solution to the common "fragile base class" problem involving ivar layouts. Dynamic ivars can also help data hiding and abstraction and can even create a confusing situation where a base class and a sub class have ivars with the same names that don't refer to the same underlying data.
In my last post, I showed how you might redesign the interface to the iPhone's UITableView if you wanted to reimplement it on the Mac using Cocoa Bindings. This time, I'll show you how to make those bindings editable in Interface Builder so you can use the entire class with no code at all.
Bindings are one of the best ways of connecting your view and model on the Mac but due to the layers of abstraction involved — and the fact that they don't exist on other platforms — bindings can seem foreign and confusing. In this post, I'll show a complex view that is traditionally implemented without bindings (the iPhone's UITableView) and show how it might be redesigned for the Mac with bindings.
You don't have to look far to find people suggesting that constructing views in code will increase the speed of your program. Since interface performance is a serious concern in iPhone development, I thought I'd look at the performance speed in creating complex iPhone UITableViewCells in code versus loading them from a NIB file.
Two different things turning two different kinds of "2". Snap.
Resolving symlinks in a path is very easy in Cocoa (it can be done in a single statement) but aliases require more work. Additionally the commands for resolving symlinks and aliases are incompatible with each other — meaning that you can resolve a path containing symlinks or aliases but not a mixture of the two. In this post, I present a category on NSString that will allow you to resolve a path containing any combination of symlinks or aliases as simply as resolving symlinks alone.
The Core Data Programming Guide clearly states that Core Data is not a database but since both Core Data and a database are ways of providing searchable, persistent storage, exactly how and why they are different may not be clear. In this post, I'll look at the way Core Data works and the reasons why its features and capabilities are different to those of common SQL databases — even though an SQL database may be used as the backing store.
As fast as computers are, heavy use of floating point functions can still slow them down. One way around this, is to use a lookup table instead of calculating floating point values at runtime. But keeping a generated table up-to-date is annoying work. In this post, I'll show you how to create a lookup table automatically using a custom build rule, making an OpenGL animation 5 times faster in the process.
This post is a response to reader questions asking how, in my previous post on Replacing Core Data Key Paths, I knew that the biggest performance problem in my initial approach was the incremental reallocation of NSMutableSet. In this post, I'll look at basic time and memory profiling on the Mac and talk about the most common types of scenario to look for when you're trying to solve performance problems.
