DAY 23

Project 3, part 1

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Walt Disney once said, “there is no magic in magic, it’s all in the details.” The same is very much true of SwiftUI: it’s easy to look at it and think there’s all sorts of magic happening to make it work so efficiently, when really if you look behind the curtain you’ll start to see exactly how it works – and in doing so gain a better understanding of how to use it.

Today is our first technique project, and we’re focusing on two fundamental components of SwiftUI: views and modifiers. We’ve been using these already, but we’ve kind of glossed over exactly how they work. Well, that ends today: we’ll be going through lots of details about what they are, how they work, and why they work as they do.

If everything goes to plan, the end result will be lots less magic and lots more detail – you’ll still enjoy using SwiftUI, but you’ll know exactly what makes it tick.

Today you have 10 topics to work through, in which you’ll learn to build custom view modifiers and custom containers, as well as start to develop your understanding of how SwiftUI actually works internally.

• Views and modifiers: Introduction
• Why does SwiftUI use structs for views?
• What is behind the main SwiftUI view?
• Why modifier order matters
• Why does SwiftUI use “some View” for its view type?
• Conditional modifiers
• Environment modifiers
• Views as properties
• View composition
• Custom modifiers

That’s a huge chunk of learning, but if you’re keen for more I have one bonus tutorial for you – it’s optional, so only complete this if you have the time: Custom containers.

How can this day be improved?

Great job on finishing another day! If you still have questions about what you learned, please send them in using this form – I'll do my best to address the most common problems in the next course update. Thank you!

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