This article is originally published at https://swiftsenpai.com on February 6, 2021.

As iOS developers, we always tend to use an actual device for testing during app development. A real device can provide an actual hardware environment similar to the production release, it also gives us a better idea about the UI / UX of our app.

However, there are certain times where iOS simulator truly shines, one of them is when debugging complex animation. The “Slow Animations” feature of a simulator can drastically reduce the app animation speed, allowing developers to clearly see the animation’s transition.

This article is originally published at https://swiftsenpai.com on January 25, 2021.

The diffable data source section snapshot is an UIKit component introduced in iOS 14. It opens up new possibilities for developers to build various types of hierarchical lists using collection view declaratively.

Even though it is such a powerful component, Apple’s official documentation does not provide much information on how it works and how to use it effectively.

In this article, I would like to share with you some interesting facts about section snapshot that I recently discovered.

With all the being said, let’s get right into it!

The Visual Descriptor

When…

This article is originally published at https://swiftsenpai.com on January 10, 2021.

The expandable date picker is a very common UI component in the Apple design system. You can find it in the iOS Reminder and Calendar App. Even though it does not come out of the box with UIKit, we can easily create one using a custom cell within a table view.

This article is originally published at https://swiftsenpai.com on December 14, 2020.

Recently I have been requested by my client to add a large title navigation bar into their app’s main screen, on top of that the large title should automatically collapse when users start scrolling.

This article is originally published at https://swiftsenpai.com on December 1, 2020.

Recently my team and I are working on an image processing app for a client. The app works pretty well on most of the aspects. Unfortunately, when we start loading HD images on screen, the app will crash occasionally due to “out of memory exception”.

In this article, I would like to share with you the problem we are facing, what is the root cause of the high memory usage and how we manage to reduce the app’s memory footprint using a simple fix recommended by the Apple engineers.

The Problem

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This article is originally published at https://swiftsenpai.com on November 15, 2020.

It’s been awhile since I covered topics related to Lottie animation. In my previous article, “ Modifying Lottie Animation with Value Providers “, I have discussed how developers can leverage different kinds of value providers to manipulate an animation during runtime based on their own needs.

In this article, let’s take a look at another less known yet pretty useful value provider in the Lottie SDK — Text Provider. As you might have guessed, a text provider allows you to change the texts within a Lottie animation during runtime.

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This article is originally published at https://swiftsenpai.com on November 7, 2020.

In my previous article, we had discussed how to add a declarative header and footer to the UICollectionView List. This week, let's take one step further and talk about how you can add a custom header to your collection view declaratively.

This is a continuation of my previous article “ Declarative UICollectionView List Header and Footer “, therefore do make sure to check it out before proceeding.

The Sample App

This article is originally published at https://swiftsenpai.com on October 19, 2020.

If you have been following my work for the past couple of months, you have probably read my articles about constructing a basic and expandable list declaratively using cell registration, content configuration, and data source snapshot.

In this article, let’s take one step further and learn how you can construct a list with header and footer declaratively without the need of using storyboard or interface builder.

For simplicity’s sake, this article will only be focusing on configuring and adding a system default header and footer, ways to add a…