Make view controller declarative

Author: MihaelIsaev

Classes/Controllers/FormViewController.swift

@@ -4,12 +4,9 @@ open class FormViewController: ViewController {
     public lazy var scrollView = ScrollView().edgesToSuperview(top: 0, leading: 0, trailing: 0).bottomToSuperview($bottom)
     public lazy var stackView = VStack().edgesToSuperview().width(to: .width, of: scrollView)
 
-    @State
-    var bottom: CGFloat = 0
-    
     open override func buildUI() {
         super.buildUI()
-        view.body { scrollView }
+        _view.body { scrollView }
         scrollView.body { stackView }
         $keyboardHeight.listen { height in
             self.bottom = -1 * height

Classes/Controllers/ViewController.swift

@@ -1,12 +1,10 @@
 import Foundation
 import UIKit
 
-open class ViewController: UIViewController {
+open class ViewController: UIViewController, DeclarativeProtocol, DeclarativeProtocolInternal, _Toucheable {
     open override var preferredStatusBarStyle: UIStatusBarStyle { statusBarStyle.rawValue }
     /// UIKitPlus reimplementation of `preferredStatusBarStyle`
-    open var statusBarStyle: StatusBarStyle { .default }
-    
-    @State public var keyboardHeight: CGFloat = 0
+    open var statusBarStyle: StatusBarStyle { _statusBarStyle ?? .default }
 
     public init (@ViewBuilder block: ViewBuilder.SingleView) {
         super.init(nibName: nil, bundle: nil)
@@ -35,10 +33,71 @@ open class ViewController: UIViewController {
         NotificationCenter.default.removeObserver(self)
     }
 
-    open func buildUI() {
-        view.backgroundColor = .white
+    // MARK: DeclarativeProtocol
+    
+    public var declarativeView: View { _view }
+    public lazy var properties = Properties<View>()
+    lazy var _properties = PropertiesInternal()
+    
+    @State public var height: CGFloat = 0
+    @State public var width: CGFloat = 0
+    @State public var top: CGFloat = 0
+    @State public var leading: CGFloat = 0
+    @State public var left: CGFloat = 0
+    @State public var trailing: CGFloat = 0
+    @State public var right: CGFloat = 0
+    @State public var bottom: CGFloat = 0
+    @State public var centerX: CGFloat = 0
+    @State public var centerY: CGFloat = 0
+    
+    var __height: State<CGFloat> { _height }
+    var __width: State<CGFloat> { _width }
+    var __top: State<CGFloat> { _top }
+    var __leading: State<CGFloat> { _leading }
+    var __left: State<CGFloat> { _left }
+    var __trailing: State<CGFloat> { _trailing }
+    var __right: State<CGFloat> { _right }
+    var __bottom: State<CGFloat> { _bottom }
+    var __centerX: State<CGFloat> { _centerX }
+    var __centerY: State<CGFloat> { _centerY }
+    
+    lazy var _view = View().background(.white).edgesToSuperview()
+    
+    open override func loadView() {
+        view = _view
+    }
+    
+    // MARK: Toucheable
+    
+    var _touchesBegan: TouchClosure?
+    var _touchesMoved: TouchClosure?
+    var _touchesEnded: TouchClosure?
+    var _touchesCancelled: TouchClosure?
+    
+    override open func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
+        super.touchesBegan(touches, with: event)
+        _touchesBegan?(touches, event)
     }
 
+    open override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
+        super.touchesMoved(touches, with: event)
+        _touchesMoved?(touches, event)
+    }
+    
+    override open func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
+        super.touchesEnded(touches, with: event)
+        _touchesEnded?(touches, event)
+    }
+    
+    open override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
+        super.touchesCancelled(touches, with: event)
+        _touchesCancelled?(touches, event)
+    }
+    
+    // MARK: Lifecycle
+    
+    open func buildUI() {}
+    
     public var isAppearedOnce = false
 
     open override func viewDidAppear(_ animated: Bool) {
@@ -61,6 +120,8 @@ open class ViewController: UIViewController {
 
     open func viewDidAppearFirstTime(_ animated: Bool) {}
 
+    @State public var keyboardHeight: CGFloat = 0
+    
     private var isSubscribedToKeyboardNotifications = false
 
     private func subscribeToKeyboardNotifications() {
@@ -113,6 +174,14 @@ open class ViewController: UIViewController {
         }
         return self
     }
+    
+    var _statusBarStyle: StatusBarStyle?
+    
+    @discardableResult
+    public func statusBarStyle(_ value: StatusBarStyle) -> Self {
+        _statusBarStyle = value
+        return self
+    }
 }
 
 // MARK: Keyboard Notifications

Classes/Extensions/UIViewController+Body.swift

@@ -2,6 +2,10 @@ import UIKit
 
 extension UIViewController {
     open func body(@ViewBuilder block: ViewBuilder.SingleView) {
-        view.body { block().viewBuilderItems }
+        if let s = self as? ViewController {
+            s._view.body { block().viewBuilderItems }
+        } else {
+            view.body { block().viewBuilderItems }
+        }
     }
 }

Classes/Protocols/BackgroundColorable.swift

@@ -0,0 +1,66 @@
+import UIKit
+
+public protocol BackgroundColorable {
+    @discardableResult
+    func background(_ color: UIColor) -> Self
+    
+    @discardableResult
+    func background(_ number: Int) -> Self
+    
+    @discardableResult
+    func background(_ state: State<UIColor>) -> Self
+    
+    @discardableResult
+    func background<V>(_ expressable: ExpressableState<V, UIColor>) -> Self
+    
+    @discardableResult
+    func background(_ identifier: FontIdentifier, _ size: CGFloat) -> Self
+}
+
+protocol _BackgroundColorable: BackgroundColorable {
+    func _setBackgroundColor(_ v: UIColor)
+}
+
+extension BackgroundColorable {
+    @discardableResult
+    public func background(_ number: Int) -> Self {
+        background(number.color)
+    }
+    
+    @discardableResult
+    public func background(_ state: State<UIColor>) -> Self {
+        background(state.wrappedValue)
+        state.listen {
+            self.background($0)
+        }
+        return self
+    }
+    
+    @discardableResult
+    public func background<V>(_ expressable: ExpressableState<V, UIColor>) -> Self {
+        background(expressable.value())
+        expressable.state.listen {
+            self.background(expressable.value())
+        }
+        return self
+    }
+}
+
+@available(iOS 13.0, *)
+extension BackgroundColorable {
+    @discardableResult
+    public func background(_ color: UIColor) -> Self {
+        guard let s = self as? _BackgroundColorable else { return self }
+        s._setBackgroundColor(color)
+        return self
+    }
+}
+
+// for iOS lower than 13
+extension _BackgroundColorable {
+    @discardableResult
+    public func background(_ color: UIColor) -> Self {
+        _setBackgroundColor(color)
+        return self
+    }
+}