https://github.com/geri-borbas/ios.package.withable
📐 Declarative UIKit in 10 lines of code.
https://github.com/geri-borbas/ios.package.withable
builder-pattern declarative declarative-programming declarative-ui decorator-pattern ios swift swift-package swift-package-manager uikit
Last synced: 6 days ago
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📐 Declarative UIKit in 10 lines of code.
- Host: GitHub
- URL: https://github.com/geri-borbas/ios.package.withable
- Owner: Geri-Borbas
- License: mit
- Created: 2022-04-09T12:11:18.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2022-04-19T11:27:52.000Z (about 3 years ago)
- Last Synced: 2024-10-15T08:02:01.858Z (7 months ago)
- Topics: builder-pattern, declarative, declarative-programming, declarative-ui, decorator-pattern, ios, swift, swift-package, swift-package-manager, uikit
- Language: Swift
- Homepage: https://blog.eppz.eu/declarative-uikit-with-10-lines-of-code/
- Size: 2.22 MB
- Stars: 28
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# Withable
📐 Declarative UIKit in 10 lines of code.
See corresponding article at [**Declarative UIKit with 10 lines of code** A simple extension instead of libraries] for more.
## How to use
With a **single extension** on `AnyObject` you can do things like this.
```Swift
class ContentViewController: UIViewController {
...
lazy var titleLabel = UILabel()
.with {
$0.text = viewModel.title
$0.textColor = .label
$0.font = .preferredFont(forTextStyle: .largeTitle)
}
...
}
```
With **any kind of object**, really.
```Swift
lazy var submitButton = UIButton()
.with {
$0.setTitle("Submit", for: .normal)
$0.addTarget(self, action: #selector(didTapSubmitButton), for: .touchUpInside)
}
```
```Swift
present(
DetailViewController()
.with {
$0.modalTransitionStyle = .crossDissolve
$0.modalPresentationStyle = .overCurrentContext
},
animated: true
)
```
```Swift
present(
UIAlertController(title: title, message: message, preferredStyle: .alert)
.with {
$0.addAction(UIAlertAction(title: "Ok", style: .default, handler: nil))
},
animated: true
)
```
```Swift
let today = DateFormatter()
.with {
$0.dateStyle = .medium
$0.locale = Locale(identifier: "en_US")
}
.string(from: Date())
```
```Swift
lazy var displayLink = CADisplayLink(target: self, selector: #selector(update))
.with {
$0.isPaused = true
$0.preferredFramesPerSecond = 120
$0.add(to: RunLoop.main, forMode: .common)
}
```
Even value types as well (after conforming to `Withable`).
```Swift
extension PersonNameComponents: Withable { }
let name = PersonNameComponents()
.with {
$0.givenName = "Geri"
$0.familyName = "Borbás"
}
```
Not to mention 3D stuff (`ARKit`, `RealityKit`, `SceneKit`).
```Swift
view.scene.addAnchor(
AnchorEntity(plane: .horizontal)
.with {
$0.addChild(
ModelEntity(
mesh: MeshResource.generateBox(size: 0.3),
materials: [
SimpleMaterial(color: .green, isMetallic: true)
]
)
)
}
)
```
## How it works
It is implemented in this `with` method. 💎
```Swift
public extension Withable {
func with(_ closure: (Self) -> Void) -> Self {
closure(self)
return self
}
}
```
The method implements pretty **classic patterns**. You can think of it as something between an unspecialized/parametric builder, or a **decorator** with customizable/pluggable decorating behaviour. See [`Withable.swift`] for all details (generics, value types).
## UIKit benefits
The package contains a couple of **convinient extensions** of `UIKit` classes what I use (probably will be moved to their own package as they grow). I left them here intentionally as they may exemplify how you can **create your own extensions** tailored for your codebases' needs.
For example, you may create a convenient **`text` decorator** for `UILabel`.
```Swift
extension UILabel {
func with(text: String?) -> Self {
with {
$0.text = text
}
}
}
```
Furthermore, you can condense your **styles to simple extensions** like this.
```Swift
extension UILabel {
var withTitleStyle: Self {
with {
$0.textColor = .label
$0.font = .preferredFont(forTextStyle: .largeTitle)
}
}
var withPropertyStyle: Self {
with {
$0.textColor = .systemBackground
$0.font = .preferredFont(forTextStyle: .headline)
$0.setContentCompressionResistancePriority(.required, for: .vertical)
}
}
var withPropertyValueStyle: Self {
with {
$0.textColor = .systemGray
$0.font = .preferredFont(forTextStyle: .body)
}
}
var withParagraphStyle: Self {
with {
$0.textColor = .label
$0.numberOfLines = 0
$0.font = .preferredFont(forTextStyle: .footnote)
}
}
}
```
With extensions like that, you can clean up view controllers.
```Swift
class ContentViewController: UIViewController {
let viewModel = Planets().earth
private lazy var body = UIStackView().vertical(spacing: 10).views(
UILabel()
.with(text: viewModel.title)
.withTitleStyle,
UIStackView().vertical(spacing: 5).views(
UIStackView().horizontal(spacing: 5).views(
UILabel()
.with(text: "size")
.withPropertyStyle
.withBox,
UILabel()
.with(text: viewModel.properties.size)
.withPropertyValueStyle,
UIView.spacer
),
UIStackView().horizontal(spacing: 5).views(
UILabel()
.with(text: "distance")
.withPropertyStyle
.withBox,
UILabel()
.with(text: viewModel.properties.distance)
.withPropertyValueStyle,
UIView.spacer
),
UIStackView().horizontal(spacing: 5).views(
UILabel()
.with(text: "mass")
.withPropertyStyle
.withBox,
UILabel()
.with(text: viewModel.properties.mass)
.withPropertyValueStyle,
UIView.spacer
)
),
UIImageView()
.with(image: UIImage(named: viewModel.imageAssetName)),
UILabel()
.with(text: viewModel.paragraphs.first)
.withParagraphStyle,
UILabel()
.with(text: viewModel.paragraphs.last)
.withParagraphStyle,
UIView.spacer
)
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(body)
view.backgroundColor = .systemBackground
body.pin(
to: view.safeAreaLayoutGuide,
insets: UIEdgeInsets(top: 30, left: 30, bottom: 30, right: 30)
)
}
}
```
I recommend to read the corresponding article at [**Declarative UIKit with 10 lines of code** A simple extension instead of libraries] to read more about the background and more examples.
## Used by Apple
Later on, I found out that on occasions **Apple uses the very same pattern** to enable decorating objects inline. These decorator functions are even uses the same `with` naming convention.
These examples below are in vanilla `UIKit`. 🍦
```Swift
let arrow = UIImage(named: "Arrow").withTintColor(.blue)
let mail = UIImage(systemName: "envelope").withRenderingMode(.alwaysTemplate)
let color = UIColor.label.withAlphaComponent(0.5)
```
* [`UIImage.withTintColor(_:)`]
* [`UIImage.withAlphaComponent(_:)`]
* [`UIImage.Configuration.withTraitCollection(_:)`]
* More examples in [`UIImage.Configuration`]
## Stored properties in extensions
In addition, the package contains an `NSObject` extension that helps creating **stored properties in extensions**. I ended up including it because I found extending `UIKit` classes with stored properties is a pretty common usecase. See [`NSObject+Extensions.swift`] and [`UIButton+Extensions.swift`] for more.
You can do things like this.
```Swift
extension UITextField {
var nextTextField: UITextField? {
get {
associatedObject(for: "nextTextField") as? UITextField
}
set {
set(associatedObject: newValue, for: "nextTextField")
}
}
}
```
## Declare constraints inline
One more secret weapon is the [`UIView.onMoveToSuperview`] extension, which is simply a closure called (once) when the `view` gets added to a `superview`. With that, you can declare the constraints in advance using this closure at initialization time, then they are added/activated later on at runtime by the time when the view has a superview. See [Keyboard Avoidance] repository for usage examples.
## License
> Licensed under the [**MIT License**](https://en.wikipedia.org/wiki/MIT_License).
[`Withable.swift`]: Withable/Withable.swift
[**Declarative UIKit with 10 lines of code** A simple extension instead of libraries]: https://blog.eppz.eu/declarative-uikit-with-10-lines-of-code/
[`NSObject+Extensions.swift`]: Withable/NSObject+Extensions.swift
[`UIButton+Extensions.swift`]: Withable/UI/UIButton+Extensions.swift
[`UIImage.withTintColor(_:)`]: https://developer.apple.com/documentation/uikit/uiimage/3327300-withtintcolor
[`UIImage.withAlphaComponent(_:)`]: https://developer.apple.com/documentation/uikit/uicolor/1621922-withalphacomponent
[`UIImage.Configuration.withTraitCollection(_:)`]: https://developer.apple.com/documentation/uikit/uiimage/configuration/3295946-withtraitcollection
[`UIImage.Configuration`]: https://developer.apple.com/documentation/uikit/uiimage/configuration
[`UIView.onMoveToSuperview`]: Withable/UIView+Extensions.swift
[Keyboard Avoidance]: https://github.com/Geri-Borbas/iOS.Blog.Keyboard_Avoidance