Cocoa with Love
Matt Gallagher: Cocoa with Love

Articles about Swift, Cocoa, software design and programming.

  • Mar 22, 2010

    Objective-C era

    Dynamic ivars: solving a fragile base class problem

    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.

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  • Mar 15, 2010

    Objective-C era

    Custom UI Bindings in Interface Builder

    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.

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  • Mar 10, 2010

    Objective-C era

    Designing a view with Bindings (UITableView on the Mac)

    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.

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  • Mar 1, 2010

    Objective-C era

    Load from NIB or construct views in code: which is faster?

    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.

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  • Feb 21, 2010

    Objective-C era

    Resolving a path containing a mixture of aliases and symlinks

    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.

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  • Feb 16, 2010

    Objective-C era

    The differences between Core Data and a Database

    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.

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  • Feb 8, 2010

    Objective-C era

    Custom build rules, generated tables and faster floating point

    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.

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  • Feb 1, 2010

    Objective-C era

    Finding the cause of performance issues in your programs

    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.

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  • Jan 25, 2010

    Objective-C era

    5 key-value coding approaches in Cocoa

    Key-value coding (KVC) is a way of decoupling a generic action from the specific properties it may need to act upon. It is most commonly associated with the NSKeyValueCoding protocol but there are a number of other ways to achieve the same effect. In this post, I look at why key-value coding is important and show you 5 different ways — each with their own particular advantages — to implement this pattern.

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