The Per Rewrite Diary: Day 11

This post is part of a series about rewriting my iOS app, Per. Per is a price per unit comparison app with a bunch of neat convenience figures, but it hasn’t been updated in years, so I’m rewriting it from scratch to eliminate a bunch of technical debt. Just because it’s not an open-source app doesn’t mean I can’t share what I learn as I go!

See the rest of the series here.

Thinking Clearly

I’m only able to do a little bit today because reasons, but there’s enough time to tackle the first of yesterday’s goals for the week: a way to clear the product list.

First, the Product model needs a way to clear the list — Swift’s removeAll() array method to the rescue!

mutating func clearItems() {
    _products.removeAll()
}

Then, I need a way to trigger this from the UI — and another UIBarButtonItem next to the add-product button should do it:

clearListBarButtonItem = UIBarButtonItem(barButtonSystemItem: .trash,
                                                      target: self,
                                                      action: #selector(handleClearListBarButtonItemTapped))

The handleClearListBarButtonItemTapped action is then pretty straightforward (remember from day 7 that the contentViewController is the one that wraps the table view):

@objc func handleClearListBarButtonItemTapped(sender: UIBarButtonItem) {
    contentViewController.productList.clearItems()
    contentViewController.loadView()
}

That’s about it! I went back and sprinkled some .isEnabled here and there to make sure that the button is disabled if there’s nothing in the list, and that was enough to call this done.

Tomorrow, I’ll start work on a form for entering product item details in the ProductItemContentViewController, which will have me diving into unfamiliar territory: creating layout in code.

Angelo Stavrow

Montreal, Canada
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Tinkerer with a strong interest for development, of both the personal and software persuasion; easily defeated with spatulas. Equal measures enthusiasm and concern for tech's effect on the world. He/him.