Customized views, enter varieties and errors


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

iOS

How NOT to construct varieties for iOS apps?

Let’s begin with an sincere assertion: I tousled with this tutorial (loads):

Constructing enter varieties for iOS apps

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

Reusability & reminiscence effectivity shouldn’t be at all times what you need.

Looks like UICollectionView shouldn’t be one of the best answer for making enter varieties, as a result of the fixed cell reusability will mess up among the anticipated conduct. It is nonetheless good for lists with “a thousand components”, however for an enter type I’d not advocate this system anymore. Yep, my mistake, sorry about it… 😬


Studying by making errors

Lengthy story quick, I made a mistake and possibly you will additionally make loads throughout your developer profession. Does this make you a nasty programmer? Under no circumstances. We’re human, we’re consistently making smaller or greater errors, however…

(Stay and) flip it into energy

Your errors will at all times stick with you, however you may study from them loads. The issue solely begins should you maintain doing the identical errors time and again, or you do not even understand that you simply’re doing one thing mistaken. It is actually arduous to take one step again and see the issue from a much bigger perspective. Generally you merely want another person to level out the problem for you, however destructive 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 realized:

  • my concepts should not 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
  • generally the “padawan” will educate the “grasp” 😉
  • knowledgeable qa group can prevent a variety of time
  • VIPER is my architectural “silver bullet”, not assortment views
  • UICollectionView based mostly type constructing shouldn’t be working…
  • …however the assortment view framework nonetheless rocks for advanced interfaces
  • have some devoted time for code cosmetics & refactor
  • use view subclasses programmatically (or SwiftUI sooner or later)

So the final level is essentially the most attention-grabbing one, let me clarify why.


Customized view subclasses from code solely

Making a UIView subclass programmatically is a comparatively simple process. 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 realized 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 format and I am utterly attempting to disregard interface builder with the tousled storyboards and nibs as nicely.

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 can be your personal init methodology, which is sort of a aid should you had been so aggravated in regards to the tousled initialization course of like I used to be. 😤

Now you may have your personal base class that you should utilize as a father or mother to your future views. After all you will must do the identical factor for nearly each UI factor, like labels, buttons, textfields, and so forth. That is a variety of work, however on a long run it’s very value it.

import UIKit

class TitleLabel: Label {

    override func initialize() {
        tremendous.initialize()

        self.textAlignment = .heart
        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),
        ]
    }
}

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

Additionally you may have some niceextensions, these can assist you with view configurations. , identical to modifiers in SwiftUI. You may even recreate the very same syntax. The underlying conduct will not be the identical, however that is one other story. 📚


What in regards to the type new builder in iOS?

Oh, yeah virtually forgot. I’ve a model new, however nonetheless very related answer. I am utilizing view subclasses as a substitute of assortment view elements, 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 may see I am nonetheless utilizing the identical view identification approach, plus I nonetheless want to have the SwiftUI-like .onTouch motion handlers. You may ask although:

Why do not you merely go along with SwiftUI?

Properly, the factor is that SwiftUI is iOS13 solely, which is simply round ~55% adoption these days, that is one of many primary causes, but in addition SwiftUI is form of incomplete.

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

Anyway, you may obtain a working instance of my newest type constructing answer in Swift 5 from GitHub. Simply search for the StackForm folder contained in the repository.

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