UIViewKit is a Swift tool that makes designing and setting up UIKit views as simple as using InterfaceBuilder, but with Swift's strong type checks. It offers a look similar to SwiftUI and has lots of easy methods for attributes, outlets, and constraints. Thanks to the @resultBuilder attribute, the code is quick to write, looks cleaner, and is more pleasing to the eye.
- SwiftUI-Style Syntax for UIKit: Embrace SwiftUI's declarative approach, but tailored for UIKit.
- No More Storyboards/Xibs: Design UI directly in code, bypassing storyboards and xib files.
- Constraint Configuration Generator: Produce complex AutoLayout setups with a single method.
- Previews for Views & Controllers: Preview your UIKit views and controllers in code, just like SwiftUI views.
class ViewController: UIViewController {
var label: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
view {
UILabel().ibOutlet(&label).ibAttributes {
$0.centerXAnchor.constraint(equalTo: view.centerXAnchor)
$0.centerYAnchor.constraint(equalTo: view.centerYAnchor)
$0.text = "Hello, world!"
}
}
}
}class ViewControllerComplex: UIViewController {
var labelTitle: UILabel!
var labelsText: [UILabel] = []
var button: UIButton = .init()
var heightConstraint: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
view {
UIStackView(axis: .vertical, spacing: 10, alignment: .center) { stackView in
UILabel().ibOutlet(&labelTitle).ibAttributes {
$0.text = "Title"
$0.font = .init(name: "Arial", size: 30)
}
UIView() { superview in
UILabel().ibOutlet(in: &labelsText).ibAttributes {
$0.topAnchor.constraint(equalTo: superview.topAnchor)
$0.leftAnchor.constraint(equalTo: superview.leftAnchor)
$0.rightAnchor.constraint(equalTo: superview.rightAnchor)
$0.bottomAnchor.constraint(equalTo: superview.bottomAnchor)
$0.text = "Label 1"
$0.textColor = .red
}
}
UILabel().ibOutlet(in: &labelsText).ibAttributes {
$0.text = "Label 2"
}
UIView().ibAttributes {
$0.leftAnchor.constraint(equalTo: stackView.leftAnchor)
$0.heightAnchor.constraint(equalToConstant: 50).ibPriority(.defaultHigh - 1).ibOutlet(&heightConstraint)
$0.backgroundColor = .yellow
}
UILabel().ibAttributes {
$0.text = "Label 3 Without Outlet"
}
UIButton().ibOutlet(&button).ibAttributes {
$0.widthAnchor.constraint(equalToConstant: 300)
$0.setTitle("Button", for: .normal)
$0.backgroundColor = .blue
$0.addTarget(self, action: #selector(didTap), for: .touchUpInside)
}
}.ibAttributes {
$0.centerXAnchor.constraint(equalTo: view.centerXAnchor)
$0.centerYAnchor.constraint(equalTo: view.centerYAnchor)
}
}
labelsText.forEach { $0.text = "toto" }
}
@objc func didTap() {
print(#function)
}
}
#if DEBUG
import SwiftUI
struct ViewControllerPreviews: PreviewProvider {
static var previews: some View {
IBRepresentableFreeFormViewController(ViewControllerComplex())
}
}
#endif