Customized views, enter kinds and errors

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Just a bit recommendation about creating customized view programmatically and the reality about why kind constructing with assortment views sucks.

iOS

How NOT to construct kinds for iOS apps?

Let’s begin with an sincere assertion: I tousled with this tutorial (rather a lot):

Constructing enter kinds for iOS apps

The factor is that this type constructing methodology solely works if the cells are at all times seen on display screen, which is sort of a uncommon case. I found this problem whereas I used to be engaged on my present challenge and a few fields have been consistently disappearing and shifting the cursor to the subsequent enter subject stopped working when the cell was out of body.

Reusability & reminiscence effectivity just isn’t at all times what you need.

Looks like UICollectionView just isn’t the very best resolution for making enter kinds, as a result of the fixed cell reusability will mess up a number of the anticipated habits. It is nonetheless good for lists with “a thousand components”, however for an enter kind I might not advocate this method anymore. Yep, my mistake, sorry about it… 😬


Studying by making errors

Lengthy story brief, I made a mistake and possibly you may additionally make rather a lot throughout your developer profession. Does this make you a nasty programmer? In no way. We’re human, we’re consistently making smaller or greater errors, however…

(Stay and) flip it into power

Your errors will at all times stick with you, however you’ll be able to study from them rather a lot. The issue solely begins in the event you maintain doing the identical errors repeatedly, or you do not even understand that you just’re doing one thing mistaken. It is actually onerous to take one step again and see the issue from an even bigger perspective. Typically you merely want another person to level out the problem for you, however damaging suggestions can be painful.

Anyway, I do not wish to be an excessive amount of philosophical, it is a Swift developer weblog ffs.

Just a few issues that I discovered:

  • my concepts aren’t at all times working, so do not belief me 100% (haha) 🤣
  • it is at all times higher to code/work in pair with another person
  • typically the “padawan” will train the “grasp” 😉
  • knowledgeable qa crew can prevent lots of time
  • VIPER is my architectural “silver bullet”, not assortment views
  • UICollectionView primarily based kind constructing just isn’t working…
  • …however the assortment view framework nonetheless rocks for complicated interfaces
  • have some devoted time for code cosmetics & refactor
  • use view subclasses programmatically (or SwiftUI sooner or later)

So the final level is probably the most fascinating one, let me clarify why.


Customized view subclasses from code solely

Making a UIView subclass programmatically is a comparatively simple job. You may load a nib file or you are able to do it straight from code. Just a few weeks in the past I’ve discovered a brand new trick, that was bugging me on a regular basis I made a brand new subclass in Swift:

Why the hell do I’ve to implement init(coder:) if I am not utilizing IB in any respect?

Additionally what the heck is happening with init(body:), I do not wish to take care of these two init strategies anymore, since I am utilizing auto structure and I am fully making an attempt to disregard interface builder with the tousled storyboards and nibs as effectively.

class View: UIView {

    @obtainable(*, unavailable)
    override init(body: CGRect) {
        tremendous.init(body: body)

        self.initialize()
    }

    @obtainable(*, unavailable)
    required init?(coder aDecoder: NSCoder) {
        tremendous.init(coder: aDecoder)

        self.initialize()
    }

    init() {
        tremendous.init(body: .zero)

        self.initialize()
    }

    func initialize() {
        self.translatesAutoresizingMaskIntoConstraints = false
    }
}

The answer: mark these silly init features as unavailable, so noone can use them anymore. The one supply of reality will likely be your personal init technique, which is sort of a aid in the event you have been so aggravated concerning the tousled initialization course of like I used to be. 😤

Now you’ve your personal base class that you should utilize as a mum or dad in your future views. In fact you may have to do the identical factor for nearly each UI aspect, like labels, buttons, textfields, and so on. That is lots of work, however on a long run it’s very price it.

import UIKit

class TitleLabel: Label {

    override func initialize() {
        tremendous.initialize()

        self.textAlignment = .middle
        self.font = UIFont.preferredFont(forTextStyle: .largeTitle)
        self.textColor = .systemBlue
    }

    func constraints(in view: UIView, padding: CGFloat = 8) -> [NSLayoutConstraint] {
        [
            self.topAnchor.constraint(equalTo: view.topAnchor, constant: padding),
            self.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: padding),
            self.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -1 * padding),
        ]
    }
}

follow could be to have subclass for each customized consumer interface part, like the first button, secondary button, title label, header label, and so on. This fashion you do not have to configure your views within the view controller, plus you’ll be able to put your steadily used constraints into the subclass utilizing some helper strategies.

Additionally you’ll be able to have some niceextensions, these may also help you with view configurations. You already know, similar to modifiers in SwiftUI. You may even recreate the very same syntax. The underlying habits will not be the identical, however that is one other story. 📚


What concerning the kind new builder in iOS?

Oh, yeah virtually forgot. I’ve a model new, however nonetheless very comparable resolution. I am utilizing view subclasses as an alternative of assortment view parts, plus the gathering view have been changed with a UIScrollView + UIStackView mixture. 🐐

class ViewController: UIViewController {

    weak var scrollView: ScrollView!
    weak var stackView: VerticalStackView!

    override func loadView() {
        tremendous.loadView()

        let scrollView = ScrollView()
        self.view.addSubview(scrollView)
        self.scrollView = scrollView
        NSLayoutConstraint.activate([/*...*/])

        let stackView = VerticalStackView()
        self.scrollView.addSubview(stackView)
        self.stackView = stackView
        NSLayoutConstraint.activate([/*...*/])
    }

    override func viewDidLoad() {
        tremendous.viewDidLoad()

        self.title = "StackForm"
        self.navigationController?.navigationBar.prefersLargeTitles = true

        let electronic mail = EmailTextField(id: "email-input", placeholder: "E-mail")
        self.stackView.addArrangedSubview(electronic mail)

        let password = PasswordTextField(id: "password-input", placeholder: "Password")
        self.stackView.addArrangedSubview(password)

        let submit = SubmitButton(id: "submit-button", title: "Submit")
        .onTouch { [weak self] _ in self?.submit() }
        self.stackView.addArrangedSubview(submit)
    }

    func submit() {
        guard
            let electronic mail = (self.view.view(withId: "email-input") as? UITextField)?.textual content,
            let password = (self.view.view(withId: "password-input") as? UITextField)?.textual content
        else {
            return
        }
        print("Account: (electronic mail) - (password)")
    }
}

As you’ll be able to see I am nonetheless utilizing the identical view identification method, plus I nonetheless desire to have the SwiftUI-like .onTouch motion handlers. You would possibly ask although:

Why do not you merely go along with SwiftUI?

Effectively, the factor is that SwiftUI is iOS13 solely, which is just round ~55% adoption these days, that is one of many predominant causes, but additionally SwiftUI is sort of incomplete.

I am making an attempt to get as shut as I can to SwiftUI, so the transition will likely be much less ache within the ass when the time comes. SwiftUI will likely be wonderful, however nonetheless it is a big leap ahead. Typically I imagine that Apple is speeding issues simply due to advertising and marketing / developer wants (yeah, we’re very impatient animals). Perhaps a easy wrapper framework round UIKit / AppKit with out the entire declarative syntax would have been a greater thought as a primary step… who is aware of… CoreKit -> AppleKit? 🤔

Anyway, you’ll be able to obtain a working instance of my newest kind constructing resolution in Swift 5 from GitHub. Simply search for the StackForm folder contained in the repository.

Thanks for studying, I am making an attempt please assist me by following on twitter and do not forget to subscribe to my month-to-month publication under.




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