Many iOS developers make serious architectural mistakes when passing data between view controllers.

There are many ways to do this, but they are not all good. Only a few of them are the best practices.

Quick and easy solutions like singletons often lead to severe problems you will discover only later.

If you want to be a skilled iOS developer, you need to know the architecture behind view controller communication.

In this article, I will show you the best practices to pass data both forward backward. We will also discuss some advanced techniques, and the solutions you should not use.

I often recommend avoiding singletons in iOS apps, especially to pass data between view controllers.

I thought that most developers knew why the singleton pattern should be avoided and what is the correct approach.

So I was surprised when I discovered that many iOS developers don’t know this.

In this article, I’ll show you what a singleton is, why you should not use singletons in your apps and what you should use instead.

Auto Layout is a complex beast to tame.

Creating adaptive apps that fit the sizes and proportions of all iOS devices is a complex problem. We can only solve it with a complex solution.

But you don’t need the full power of Auto Layout all the time.

Most apps have fairly straightforward interfaces. Most of the time, you can go a long way by only using Auto Layout’s basic features in an app’s storyboard.

That’s the Pareto Principle at play: learn the 20% of Auto Layout’s functionality that covers 80% of the cases.

From there, you can expand and include the what you miss to solve the problems you have at hand.

Many design patterns guide iOS architecture. People have varying opinions on what constitutes good app architecture in iOS.

I, for one, have issues with all the modern iOS architecture “best practices.”

Their main problem is that they only focus on massive view controllers. While this is a problem that we need to address, it’s far from being the only one.

After years of working in many teams with diverse backgrounds, I created the Lotus MVC Pattern to address these issues.

I have taught this new pattern to my students and email subscribers for some time now. I presented it publicly for the first time at MobileFest in Kiev, and this is the first time I show it publicly in a detailed article.

This article revolves around UIKit apps, but most of the ideas still apply to SwiftUI, since the Model-View-Controller pattern remains essential.

Finding your way in the navigation of a complex iOS app can be quite complicated.

I know this from experience.

During many years of freelancing, I joined many projects at an advanced stage of development.

When you browse the classes in a project, there is a disconnect from what you see in code and what you see in the app.

And when you find a bug in some screen, how do you know in which class to look?

To solve the problem of visualizing the navigation flow of an app, Apple introduced the concept of storyboards in iOS development.