In this tutorial, we will learn how to implement a circular loading indicator in Swift. By the end, you will have a reusable UI element you can use in your apps to suit your needs.

In short, this is what we will master in this article:

• Create a circular shape and path using CAShapeLayer and UIBezierPath
• Animate circular drawing using CABasicAnimation and CAKeyframeAnimation
• Combine several animations using CAAnimationGroup

This is the result we are going to achieve:

Today, we will learn how to use NSCache in Swift to cache images inside a UICollectionView.

In short, this is what you will master in this tutorial:

• Understanding what an NSCache is and how to use it.
• Creating a centered UICollectionView layout.
• Executing image-loading tasks on a background thread.
• Understanding why it is better to use an NSCache instead of a plain Dictionary when we want to cache heavy objects.

This is what we will have at the end of this article:

In this article, we will learn how to limit the number of ongoing network requests using a DispatchSemaphore.

Limiting resource-heavy operations allows us to manage thread resources more efficiently. For example, when you have a task to simultaneously fetch ten high-quality images, it is useful to allow the execution of only one or two image loading operations at a time.

In short, this is what you will master in this tutorial:

• Executing tasks on a background DispatchQueue.
• Leveraging a DispatchSemaphore and setting the max number of concurrent operations.
• Understanding the difference between using sync and async executions.

Let’s Start

First, let’s create a URL, a background DispatchQueue, and a DispatchSemaphore with a value of…

Consider this case: A specific screen in your app requires firing two different requests at the same time. Your goal is to update the UI only after both of them complete. In this tutorial, we will learn how to observe the completion of several network requests using Combine.

We will leverage a powerful .zip operator that allows us to receive a tuple containing events from several upstream Publishers.

In short, these are the topics you will master in this tutorial:

• Combine several Publishers using the .zip operator.
• Perform network requests using a built-in URLSessionDataTask publisher.
• Get transformed publishers using the .map …

In this article, we will learn how to create a reusable UI element — a bottom sheet.

At the end of the tutorial, you will have a finished component you can easily copy and paste into your app and use to suit your needs.

This is what we are going to build:

In this article we will learn about the difference between leading and left, trailing and right constraints in Swift.

In short, by setting the leading constraint we set the starting point of a view, while the trailing constraint sets the ending point. If we are using English language in our app, leading and left anchors are the same thing, just like the trailing and right ones. But if we add support for RTL (Right-to-left) languages like Arabic, Hebrew, or Urdu, leading will mean right, and trailing will mean left.

Now let’s explore this difference on a simple example.

Let’s Start

Our ViewController has a rounded UIView containing a…

In this article, we will learn how to architect and create an efficient and easy to use networking layer by leveraging Combine publishers, Codable, CustomStringConvertible protocol, and a custom Endpoint struct.

At the end of the tutorial, you will have a ready-to-use implementation that you can easily copy and paste in your app and expand it the way you want.

The full source code is available at the bottom of the article.

Let’s Start

Before we dive into the code, let’s first outline all components of our networking layer:

• Endpoint — a handy struct that has path and queryItems properties. By defining extensions on it, we can conveniently create a base URL of our REST APIs, define specific endpoints and headers (that will make more sense to you as we start implementing it, so don’t worry). …

In this tutorial, we will learn how to easily observe UserDefaults using a Combine publisher.

Without further ado, let’s get started.

Let’s Start

Consider a case where you want to persist a game’s music volume in UserDefaults. You also want to observe the change and react accordingly. So our first step is to define the following extension:

As we can see, the getter returns the Float value for the music_volume key and the setter sets the new value for that key.

Next, let’s import Combine and add the subscriptions property to store our future subscription:

Now we can add the actual subscription inside the viewDidLoad()…