ViewDSL

Heavily inspired from UIKitDSL but want some functionalities added.

Have you known Anko? That's beauty of DSL as first class citizen.

Dependency Management

CocoaPod

ViewDSL available through CocoaPod! Yay!

pod "ViewDSL"

Carthage

github "muizidn/viewdsl"

Constraint?

No, ViewDSL doesn't handle constraint for you. It let you choose any constraint approach avilable or using other 3rd party library.

Base DSL

With ViewDSL you can build UI in declarative way.

UIView().add { (v: UIView) in
  
}

Unfortunately, ViewDSL force you to explicitly declare type of instance to be added. That isn't better from UIKitDSL. Agreed.

Lets take a look below example. ViewDSL give you functionality to initialize your UIView in some fun way.

class EqualStackView: UIStackView {
  func layoutSubviews() {
    super.layoutSubviews()
    distribution = .fillEqually
    spacing = 10
  }
}

let stack = EqualStackView { s in
  s.axis = .vertical
  
  s.add { (s: EqualStackView) in
    s.axis = .horizontal
    
    s.add { (b: UIButton) in
      b.setTitle("Yes", for: .normal)
      b.backgroundColor = .green
    }
    s.add { (b: CustomButton) in
      b.title = "No"
      b.bgColor = .red
    }
  }
}

Thats the power from ClosureInit! But you must implement init() method in your custom class to get it's support. Funny because all NSObject classes and its derived classes must have implentation of init() right? So UIView classes!

The way ViewDSL ask you to declare explicitly type of instance to be added gives you power to make all your custom classes works with ViewDSL out-of-the-box. But sure, you can make your custom function to make your DSL more like Anko or UIKitDSL.

extension ViewDSL {
  @discardableResult
  func stack(_ closure: (UIStackView) -> Void) -> UIStackView {
     return add { (s: UIStackView) in
       closure(s)
     }
  }
}

The UIKitDSL's like implementation has been provided for you. But it doesn't included in library by default. You must manually copy-paste it to your application. All method prefixed with u to indicate it produces UIKit class instance.

DelegatedDSL

You want to separate your common Button to reuse it later? Meet DelegatedDSL!

// Look Here I'm using my custom DSL from previous code
view.stack {
  $0.axis = .vertical
  
  // And I want to added by common button to current view
  $0.dsl(delegatedTo: blueButton(_:))
}

// I'm using function to put my common button implementation
func blueButton(_ dsl: ViewDSL) {
    dsl.add { (b: UIButton) in
        b.backgroundColor = .blue
    }
}

LayoutBuilderDSL

This protocol will fit if you need complex UI implementation to be put in different file.

class ProfileLayout: LayoutBuilderDSL {
    let name: UITextField
    let email: UITextField
    let saveButton: UIButton

    init(name: String, email: String) {
        name = UITextField {
          $0.text = name
        }
        email = UITextField {
          $0.text = email
        }
        saveButton = UIButton {
          $0.setTitle("Save", for: .normal)
        }
    }

    func layout(_ dsl: ViewDSL) {
        dsl.add(name)
        dsl.add(email)
        dsl.add(saveButton)
    }
}

stack.dsl(delegatedTo: ProfileLayout(name: "Egg-boy", email: "eggboy@youknow.com"))

If you want to use *.self style, you can implement InitializableLayoutBuilderDSL

extension ProfileLayout2: ProfileLayout, InitializableLayoutBuilderDSL {
  init() {
    super.init(name: "", email: "")
  }
}

stack.dsl(withInstanceOf: ProfileLayout2.self)

Beautiful!!

And some you may find it in Example project! Have a try!

Supporting 3rd Party Library

This Library AloeStackView mimics UIStackView with functionalities added. It is a subclass of UIScrollView which made default ViewDSL.put(_:) implementations for either UIView or UIStackView invalid. You should support it your self. Is it possible?

You may want to read this post before proceed Override Protocol Extension Default Implementation in Swift

ViewDSL make use of Dynamic Dispatch to determine what implementation of put(_:) to be called. And because either the protocol and it requirement is an @objc then we can override put(_:) for our AloeStackView.

extension AloeStaskView {
  @objc
  public override put(_ view: UIView) {
    addRow(view, animated: true)
  }
}

view.add { (aloe: AloeStackView) in
  aloe.add { (b: UIButton) in
    b.setTitle("Click Me!", for: .normal)
  }
}

muizidn/viewdsl