Choosing Between NSOperation and Grand Central Dispatch

While NSOperation and NSOperationQueue have been available since iOS 2, Grand Central Dispatch, GCD for short, was introduced in iOS 4 and OS X 10.6 Snow Leopard. Both technologies are designed to encapsulate units of work and dispatch them for execution. Because these APIs serve the same goal, developers are often confused when to use which.

in Concurrency

Is Core Data Slow

If Core Data is slow, then you are most likely using a very big data set or not correctly using the framework. The latter is the most common issue. Core Data was designed with speed and efficiency in mind. It only fetches the data your application needs and fills in the gaps as your application asks for more data.

in Core Data

Is Core Data a Relational Database

This question keeps popping up time and time again and it's a good question if you are new to Core Data. What you need to know is that Core Data is not a database. That said, when working with Core Data it acts as a relational database hence the confusion.

in Core Data

How to Create an Abstract Class in Swift

The title of this tutorial is a bit misleading because the Swift programming language doesn't support abstract classes. Fortunately, there are workarounds. In this tutorial, we take a look at two alternatives to the abstract class pattern.

in Patterns

Is Core Data Encrypted

Does Core Data encrypt the persistent store it manages? The answer is yes and no. Core Data doesn't encrypt the data you store in the persistent store, but it is possible to enable encryption. Let me explain what that means and how it works.

in Core Data

Managing View Controllers With Container View Controllers

Have you ever wondered how tab bar controllers and navigation controllers do their work? Even though it may seem as if UITabBarController and UINavigationController are magical classes, they are nothing more than UIViewController subclasses.

in Patterns

Is Core Data Available on All Devices

Apple's persistence framework was introduced more than a decade ago so it's shouldn't surprise you that it is available on every platform, iOS, tvOS, macOS, iPadOS, watchOS, and Mac Catalyst.

in Core Data

Model-View-ViewModel in Swift

Model-View-Controller, or MVC for short, is a widely used design pattern for architecting software applications. Cocoa applications are centered around MVC and many of Apple's frameworks are impregnated by the pattern.

in Patterns

Value Types and Reference Types in Swift

When talking about object-oriented programming, most of us intuitively think about classes. In Swift, however, things are a bit different. While you can continue to use classes, Swift has a few other tricks up its sleeve that can change the way you think about software development. This is probably the most important shift in mindset when working with Swift, especially if you're coming from a more traditional object-oriented programming language like Ruby or Objective-C.

in Patterns

Dependency Injection in Swift

Many developers cringe when they hear the words dependency injection. It's a difficult pattern and it's not meant for beginners. That's what you are made to believe. The truth is that dependency injection is a fundamental pattern that is very easy to adopt.

in Patterns

Namespaces in Swift

To avoid naming collisions with other libraries and frameworks, an Objective-C class needs to have a unique name. That's the reason Apple uses prefixes on Objective-C classes, such as UIView, CGRect, and CALayer. Swift modules make the need for class prefixes obsolete.

in Patterns

Combining Observables with RxSwift's Zip Operator

RxSwift Essentials

RxSwift defines a number of operators to combine two or more observables into a single observable. Each of these operators serves a specific purpose. In this episode, I show you how to use the zip operator to combine observables.

in RxSwift