This technique just isn’t working, since cells within the kind are going to be reused and this results in some inconsistency… please learn my different publish. 🤷♂️
CollectionView and enter types
My CollectionView framework simply bought a HUGE replace. There are many new adjustments, however one of many largest enchancment is the way in which I take care of view fashions. Up to now, you had to make use of lengthy operate names in your view mannequin together with the generic view & mannequin class names. When you’ve got ever learn my final UICollectionView information it is best to know what I am speaking about. Excellent news: I’ve a method higher resolution now! 😉
This replace not simply cleans up my code loads, however it permits me so as to add customized view mannequin handlers, so I can work together with enter fields, toggles, and so forth. in a ridiculously simple method. One other enormous enchancment is that I began to make use of view identifiers. It was unintended discovery, I solely needed to search for another resolution for figuring out views by tags, then I had this sensible concept: why not search for cells by ids as properly?
Consequently I am now in a position to create types by utilizing the framework. I nonetheless consider that assortment views are the last word constructing blocks for a lot of the functions. Yeah, you may nonetheless say that there is no such thing as a silver bullet, however I am simply tremendous if this resolution can cowl 90% of the my use-cases. In spite of everything, a lot of the apps are simply visualizing JSON information in a pleasant, or not-so-nice method. 🤷♂️ #sarcasm
Reusable kind elements
Let’s construct a kind by utilizing the model new framework. To start with, you may have to combine it by utilizing a package deal supervisor. I actually hope that in a number of weeks we will use Swift Package deal Supervisor, till than you it is best to go along with CocoaPods or carthage.
# cocoapods
supply 'https://github.com/CoreKit/CocoaPods.git'
pod 'CollectionView', '~> 2.0.0'
# carthage
github "CoreKit/CollectionView" "2.0.0"
Now let’s create a reusable cell for our enter fields. Be happy to make use of a xib file as normal, the one distinction within the implementation goes to be that I take away the goal listener within the reset technique. We’ll add one afterward within the view-model. 🎯
import Basis
import CollectionView
class InputCell: Cell {
@IBOutlet weak var textField: UITextField!
override func reset() {
tremendous.reset()
self.textField.removeTarget(nil, motion: nil, for: .editingChanged)
}
}I am additionally going to create a easy entity for displaying a placeholder if the shape area is empty and storing the precise worth of the enter area, let’s name this InputEntity.
import Basis
struct InputEntity {
var placeholder: String
var worth: String?
}Now the toughest half: making a connection between the view and the mannequin.
import Basis
import CollectionView
class InputViewModel: ViewModel<InputCell, InputEntity> {
var editingChangeHandler: ViewModelHandler?
override var top: CGFloat {
return 60
}
override func updateView() {
self.view?.textField.placeholder = self.mannequin.placeholder
self.view?.textField.textual content = self.mannequin.worth
self.view?.textField.addTarget(self,
motion: #selector(self.editingChanged(_:)),
for: .editingChanged)
self.view?.textField.addTarget(self,
motion: #selector(self.editingDidEnd(_:)),
for: .editingDidEnd)
}
func onEditingChange(_ handler: @escaping ViewModelHandler) -> Self {
self.editingChangeHandler = handler
return self
}
@objc func editingChanged(_ textField: UITextField) {
self.mannequin.worth = textField.textual content
self.editingChangeHandler?(self)
}
@objc func editingDidEnd(_ textField: UITextField) {
print("nothing-to-do-here-now...")
}
}It is fairly a fancy view mannequin, however it will probably do loads as properly. The very first thing that it is best to perceive is the ViewModelHandler which is principally a generic alias that you would be able to make the most of within the view fashions. It provides you the power to go across the type-safe view-model for the callbacks. You will see that afterward.
The second main change is the updateView technique, which is used to replace the view based mostly on the info coming from the mannequin. I am additionally including my goal listeners to my view, so I can deal with consumer enter instantly contained in the view-model class.
The onEditingChange technique is the “public” api of the view-model. I take advantage of the on prefix now for including handlers, and listeners to my view-models. It principally calls the saved block if a change occasion occurs. You’ll be able to add as many occasion handler blocks as you need. I actually hope that you will get the dangle of this method.
Another factor: returning the the peak of the cell is a one-liner now! 🎊
Composing types and extra The plan is for now to have an enter kind with two enter fields. One for the e-mail deal with, the opposite goes for use for the password. The trick goes to be that this time I will not present you all the code, however you need to determine the remaining.
Nevertheless I am going to present you every thing that you will ever have to know with a view to make your individual types, even some complicated ones. Don’t fret, it is only a few traces of code.
import UIKit
import CollectionView
class ViewController: CollectionViewController {
override func viewDidLoad() {
tremendous.viewDidLoad()
let grid = Grid(columns: 1, margin: UIEdgeInsets(all: 16), padding: .zero)
self.collectionView.supply = .init(grid: grid, [
[
InputViewModel(id: "email-input", .init(placeholder: "Email", value: nil))
.onEditingChange { viewModel in
guard let passwordViewModel = viewModel.by(id: "password-input") as? InputViewModel else {
return
}
passwordViewModel.model.value = viewModel.model.value ?? ""
passwordViewModel.updateView()
},
InputViewModel(id: "password-input", .init(placeholder: "Password", value: nil)),
],
])
self.collectionView.reloadData()
}
}Should you’ve ever labored with my assortment view framework, it is best to know that I all the time use a grid system, as a result of I do not actually prefer to calculate numbers.
The supply is a set of view-models, grouped by sections. The one fascinating half right here is that sources can now be initialized with an array of sections and view-models.
Should you initialize a view-model with and identifier, afterward you may question that one by the id. That is precisely whats taking place contained in the modifying change handler block. Each view-model has the power to return another view-model by the id. View-models are type-safe by default, the viewModel handed contained in the block too, due to the generic ViewModelHandler alias.
So on this little instance, for those who kind one thing into the primary enter area, the very same textual content will seem within the second textual content area. You may get all of the view fashions by id once you want them. For instance if you need to submit this way, you may seize the e-mail and password fields by utilizing the identical method.
Constructing a login kind
I problem you to construct a login kind by yourself by utilizing my framework. I assure yout that it should not take greater than 30mins of labor. I am going to present you the ultimate view controller that I might use, so this would possibly provides you some assist.
If you wish to boost issues somewhat bit, you may even add a checkbox for accepting the privateness coverage. The primary concept right here is that it is best to create reusable elements for each single merchandise in your kind. So for instance a ToggleView with a corresponding view-model could be a superb method (additionally works for buttons). 🤫
Right here is the ultimate trace, you solely must make your individual view-models and views…
import UIKit
import CollectionView
class ViewController: CollectionViewController {
enum Ids: String {
case electronic mail = "email-input"
case password = "password-input"
case privacyPolicy = "privacy-policy-checkbox"
case submit = "submit-button"
}
override func viewDidLoad() {
tremendous.viewDidLoad()
let grid = Grid(columns: 1, margin: UIEdgeInsets(all: 16), padding: .zero)
self.collectionView.supply = .init(grid: grid, [
[
InputViewModel(id: Ids.email.rawValue, .init(placeholder: "Email", value: nil))
.onEditingEnd { viewModel in
guard let passwordViewModel = viewModel.by(id: Ids.password.rawValue) as? InputViewModel else {
return
}
passwordViewModel.view?.textField.becomeFirstResponder()
},
InputViewModel(id: Ids.password.rawValue, .init(placeholder: "Password", value: nil, secure: true))
.onEditingEnd { viewModel in
viewModel.view?.textField.endEditing(true)
},
],
[
ToggleViewModel(id: Ids.privacyPolicy.rawValue, .init(label: "Privacy policy", value: false))
.onValueChange { viewModel in
guard let submitViewModel = viewModel.by(id: Ids.submit.rawValue) as? ButtonViewModel else {
return
}
var model = submitViewModel.model
model.enabled = viewModel.model.value
submitViewModel.model = model
submitViewModel.updateView()
},
],
[
ButtonViewModel(id: Ids.submit.rawValue, .init(title: "Submit", enabled: false))
.onSubmit { viewModel in
guard
let emailViewModel = viewModel.by(id: Ids.email.rawValue) as? InputViewModel,
let passwordViewModel = viewModel.by(id: Ids.password.rawValue) as? InputViewModel
else {
return
}
},
],
])
self.collectionView.reloadData()
}
}That is it for now, an virtually full login kind, with only a few traces of code. In fact there may be an underlying framework, however for those who verify the supply code, you may really see that it accommodates nothing that might be thought of as black magic. 💫