iExpense: Wrap up

Paul Hudson    @twostraws    October 26th 2023

Although the app we were building wasn’t itself difficult, getting there took quite a bit of learning – we had to cover UserDefaults, Codable, sheet(), onDelete(), @Observable, and more. Some of those things – particularly UserDefaults and Codable – have only been introduced at a high level in this project, which is intentional; we’ll be getting into them more later on.

Now that your SwiftUI skills are coming along, I hope you noticed we were able to skip past some parts with very little explanation. For example, you know very well how to create forms with text fields and pickers because we’ve already covered that extensively, which means we can spend our time focusing on new stuff.

Review what you learned

Anyone can sit through a tutorial, but it takes actual work to remember what was taught. It’s my job to make sure you take as much from these tutorials as possible, so I’ve prepared a short review to help you check your learning.

Click here to review what you learned in this project.

Challenge

One of the best ways to learn is to write your own code as often as possible, so here are three ways you should try extending this app to make sure you fully understand what’s going on.

1. Use the user’s preferred currency, rather than always using US dollars.
2. Modify the expense amounts in ContentView to contain some styling depending on their value – expenses under $10 should have one style, expenses under $100 another, and expenses over $100 a third style. What those styles are depend on you.
3. For a bigger challenge, try splitting the expenses list into two sections: one for personal expenses, and one for business expenses. This is tricky for a few reasons, not least because it means being careful about how items are deleted!

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