The Blog

Real time data exchange using web sockets in iOS 13

Apps send and receive data all the time. Some apps mostly read data from the network, others are more focussed on sending data to servers. Depending on your needs, you might need to be able to send data to a server as quickly as possible, or maybe you need to receive new data as soon as it’s available from a server. Every app has different needs and several mechanisms exist to streamline network communication. In this post week’s blog post, Read more…

By donnywals, ago

Announcing: Advent of Swift

December has always been a month of sharing for me. Sharing food and experiences with family, celebrating the end of what has (hopefully) been a wonderful year, reflecting and setting goals for the new year. And this year, I have decided to share something really special with the iOS community. In December I will publish a new blog post every day until Christmas eve. That’s 24 blog posts in total. And since I want this whole endeavor to be about Read more…

By donnywals, ago

Configuring projects with xcconfig

Sometimes you want to be able to install two versions of your app side by side, for example, a development version and a release version that show up as individual apps by giving them different bundle identifiers. And maybe they should also use different versions of your REST API depending on the type of build you’re using. In this week’s Quick Tip I will show you how you can manage this using xcconfig files. Creating and using your xcconfig file Read more…

By donnywals, ago

Building flexible components with generics and protocols

Recently I wanted to build a generic data source layer. This data source would be able to return pretty much anything from a local cache, or if the local cache doesn’t contain the requested object, it would fetch the object from a server and then cache the result locally before returning it to me. To achieve this, I figured that I would write a generic local cache, a generic remote cache and a wrapper that would combine both caches, allowing Read more…

By donnywals, ago

Add iOS 12 support to a new Xcode 11 Project

When you create a new project in Xcode 11, you automatically get the new SceneDelegate for free. This is great if you want to build an app that’s for iOS 13 and newer but as soon as you change your deployment target to an iOS version that’s lower than iOS 13, your app will have trouble compiling. In this Quick Tip, I will show you how to update your project in order to make it compile for iOS 12 and Read more…

By donnywals, ago

When to use weak self and why

We all want to write good, beautiful and stable code. This includes preventing memory leaks, which we can, using [weak self] when writing a closure that needs access to self. But what’s the real reason for needing this weak capture? And do we need it all the time? In this week’s Quick Tip, I want to help you find an answer to this question so you can make more informed decisions about your capture lists in the future. We’ll go Read more…

By donnywals, ago

Adding support for multiple windows to your iPadOS app

Now that Apple has split iPadOS into a separate OS, and launched Catalyst to enable developers to compile their iPad apps for the Mac, there’s a whole new multi-window paradigm we must understand and cater for. Up until this year, we only had to worry about a single window for our iOS applications. This meant that we never had to worry about the user being at two places in our app at the same time. For instance, what would happen Read more…

By donnywals, ago

Uploading images and forms to a server using URLSession

One of those tasks that always throws me off balance is building a form that allows users to upload a form with a picture attached to it. I know that it involves configuring my request to be multipart, that I need to attach the picture as data and there’s something involved with setting a content disposition. This is usually about as far as I go until I decide it might be a good time to go to github.com and grab Read more…

By donnywals, ago

Understanding the iOS 13 Scene Delegate

When you create a new project in Xcode 11, you might notice something that you haven’t seen before. Instead of only creating an AppDelegate.swift file, a ViewController.swift, a storyboard and some other files, Xcode now creates a new file for you; the SceneDelegate.swift file. If you’ve never seen this file before, it might be quite confusing to understand what it is, and how you are supposed to use this new scene delegate in your app. By the end of this Read more…

By donnywals, ago

When to use map, flatMap and compactMap

Any time you deal with a list of data, and you want to transform the elements in this list to a different type of element, there are several ways for you to achieve your goal. In this week’s Quick Tip, I will show you three popular transformation methods with similar names but vastly different applications and results. By the end of this post, you will understand exactly what map, flatMap and compactMap are and what they do. You will also Read more…

By donnywals, ago