Whenever I'm programming, I have a goal in mind, generally a problem to solve. I want my solutions to be simple, yet elegant and reliable. Thankfully, Swift is a great language for this. The language is safe, its syntax is beautiful with great readability. The way Swift handles nullability with Optional contributes greatly to its safety. Can you imagine having a language where you don't know whether something could be nil? Well... languages like Objective-C and Java required developers to constantly check for null or nil values to prevent crashes. I'm sure you can imagine that this would go wrong...

No app is truly complete without some subtle shadows. Especially now that Google's Material Design is showing us that shadows are cool again we need a way to properly add them in our apps. In my previous post I wrote about a way to create a custom UICollectionView layout. There was one problem with that post though, that shadows are incredibly heavy on the iPhone and scrolling stutters. So can we fix this? The answer is yes and the solution is (surprisingly) easy. A Google search led me to this Stackoverflow question about shadows. The solution I tried first was to simple...

Note: This blog post has been updated for Xcode 11 and Swift 5 👍🏼 If you’re looking to learn more about the new collection view layout techniques that were introduced in iOS 13, this post should contain everything you need. If you've ever built an iOS app that uses some kind of grid layout or displays a list in a way that doesn't fit a UITableView you have probably used a UICollectionView. This component allows for very simple grid layout creation and it even allows you to dynamically change layouts with beautiful animations. UICollectionView becomes even more powerful and flexible...

There are times when you need to extract a subset of an array. For example, you might need to find all elements in an array at an odd index. Or maybe you need all items at an even index. In other words, you're looking for every "other" element in an array. This might seem like a non-trivial task and you may have tried this before using a for loop as follows: var itemsAtEvenIndices = [Int]() let allItems = [1, 2, 3, 4, 5, 6, 7] var index = 0 for item in allItems { if index % 2 == 0...

In 2015 Apple announced Protocol extensions at WWDC and went on to explain the idea of Protocol Oriented Programming (video here), I think every iOS developer got really exited when they saw this. The ability to add default implementations to protocol methods through extensions makes it seem like everything we will ever build can and should be protocol based instead of inheritance based like we do in classical OOP. In this post, we'll explore protocols and protocol extensions to see what we can make them do. Taking advantage of Protocols today To take advantage of the awesomeness of Protocols we...

We can all agree that using png sprites for icons is not the most modern (or best) way to present icons on the web. Png is a rasterized format which means that if you try to make the image (or icon) larger, the quality will become worse. When browsers started properly supporting @font-face and svg some people chose to use icon fonts to serve their icons, others chose svg sprites to do this. These methods share the big benefit of scalability. This matters because our websites get viewed on many devices and you want your icons to be crisp on every...

A few days ago I found this article that argues for using rem units when defining font sizes. Generally speaking this is good advice. The rem comes with great predictable behavior, just like pixels do. But the rem also comes with accessibility advantages. When a user changes the font size in their browser settings, the rem and em unit will both respect that and resize accordingly while the pixel unit doesn't. That's great news for the user. But how do you choose between rem or em? Time to go in depth on what these units do. First I'll explain how each unit works...

One of the beautiful things about being a developer is that many of us actually have the opportunity to take an activity we enjoy, and make it our job. Many developers are happy to do some extra work or learn something when they're at home or in the weekend just because they are so eager to learn and play. While this is pretty awesome, it won't last forever. You won't be motivated to learn every single day. Especially once you start doing development as a full-time job. I experience this as well, sometimes I have a couple of days or...

The Flexbox module for css was built with the intent to make a more robust, less hacky way to layout elements on pages. When you're building a webpage you often don't know how high or wide every element could or should be. This can cause problems in certain layouts which lead to ugly hacks. Flexbox solves this widespread layout issue. The module has been in development for quite some time and the W3C gave the spec a "last call working draft" status back in september of 2014. The browser support for this module is very good if you don't have...

In the war between native and web apps there's a few aspects that make a native app superior to a web app. Among these are features like push notifications and offline caching. A native app, once installed, is capable of providing the user with a cache of older content (possibly updated in the background) while it's fetching new, fresh content. This is a great way to avoid loading times for content and it's something that browser vendors tried to solve with cache manifests and AppCache. Everybody who has tried to implement offline caching for their webpages will know that the AppCache manifest files...