How NOT to construct kinds for iOS apps?
Let’s begin with an trustworthy assertion: I tousled with this tutorial (loads):
Constructing enter kinds for iOS apps
The factor is that this way 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 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 among the anticipated conduct. It is nonetheless good for lists with “a thousand parts”, however for an enter kind I might not suggest this system anymore. Yep, my mistake, sorry about it… 😬
Studying by making errors
Lengthy story quick, I made a mistake and possibly you may additionally make loads throughout your developer profession. Does this make you a foul programmer? In no way. We’re human, we’re consistently making smaller or larger 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 for those who hold doing the identical errors many times, or you do not even understand that you just’re doing one thing flawed. It is actually arduous to take one step again and see the issue from an even bigger perspective. Generally you merely want another person to level out the problem for you, however destructive suggestions may also be painful.
Anyway, I do not wish to be an excessive amount of philosophical, it is a Swift developer weblog ffs.
A number of 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
- generally the “padawan” will educate the “grasp” 😉
- an expert qa group can prevent a number 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 advanced 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 straightforward job. You may load a nib file or you are able to do it straight from code. A number of 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 format and I am utterly making an attempt to disregard interface builder with the tousled storyboards and nibs as nicely.
class View: UIView {
@accessible(*, unavailable)
override init(body: CGRect) {
tremendous.init(body: body)
self.initialize()
}
@accessible(*, 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 no-one can use them anymore. The one supply of reality can be your individual init methodology, which is sort of a aid for those who had been so aggravated concerning the tousled initialization course of like I used to be. 😤
Now you could have your individual base class that you need to use as a mum or dad to your future views. In fact you may must do the identical factor for nearly each UI aspect, like labels, buttons, textual content fields, and so on. That is a number 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),
]
}
}A superb follow will be to have subclass for each customized person 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 may put your steadily used constraints into the subclass utilizing some helper strategies.
Additionally you may have some good extensions, these may help you with view configurations. You understand, 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 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 e mail = EmailTextField(id: "email-input", placeholder: "E mail")
self.stackView.addArrangedSubview(e 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 e 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: (e mail) - (password)")
}
}As you may see I am nonetheless utilizing the identical view identification method, plus I nonetheless desire to have the SwiftUI-like .onTouch motion handlers. You may ask although:
Why do not you merely go along with SwiftUI?
Nicely, the factor is that SwiftUI is iOS 13 solely, which is just round ~55% adoption these days, that is one of many major 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 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 consider 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 kind constructing resolution in Swift 5 from GitHub. Simply search for the StackForm folder contained in the repository.