Initial work supporting controllers

Author: bbrk24

Sources/UIKitBackend/BaseWidget.swift

@@ -1,26 +1,29 @@
 import SwiftCrossUI
 import UIKit
 
-final class ScrollWidget: WrapperWidget<UIScrollView> {
+final class ScrollWidget: ContainerWidget, UIScrollViewDelegate {
+    private var scrollView = UIScrollView()
     private var childWidthConstraint: NSLayoutConstraint?
     private var childHeightConstraint: NSLayoutConstraint?
-
-    private let innerChild: BaseWidget
-
-    init(child innerChild: BaseWidget) {
-        self.innerChild = innerChild
-        super.init(child: UIScrollView())
-
-        child.addSubview(innerChild)
-
-        NSLayoutConstraint.activate([
-            innerChild.topAnchor.constraint(equalTo: child.contentLayoutGuide.topAnchor),
-            innerChild.bottomAnchor.constraint(equalTo: child.contentLayoutGuide.bottomAnchor),
-            innerChild.leftAnchor.constraint(equalTo: child.contentLayoutGuide.leftAnchor),
-            innerChild.rightAnchor.constraint(equalTo: child.contentLayoutGuide.rightAnchor),
-        ])
+    
+    private lazy var contentLayoutGuideConstraints: [NSLayoutConstraint] = [
+        scrollView.contentLayoutGuide.leadingAnchor.constraint(equalTo: child.view.leadingAnchor),
+        scrollView.contentLayoutGuide.trailingAnchor.constraint(equalTo: child.view.trailingAnchor),
+        scrollView.contentLayoutGuide.topAnchor.constraint(equalTo: child.view.topAnchor),
+        scrollView.contentLayoutGuide.bottomAnchor.constraint(equalTo: child.view.bottomAnchor)
+    ]
+    
+    override func loadView() {
+        view = scrollView
+        scrollView.translatesAutoresizingMaskIntoConstraints = false
+        scrollView.delegate = self
     }
-
+    
+    override func viewWillLayoutSubviews() {
+        NSLayoutConstraint.activate(contentLayoutGuideConstraints)
+        super.viewWillLayoutSubviews()
+    }
+    
     func setScrollBars(
         hasVerticalScrollBar: Bool,
         hasHorizontalScrollBar: Bool
@@ -29,8 +32,8 @@ final class ScrollWidget: WrapperWidget<UIScrollView> {
             case (true, true):
                 childHeightConstraint!.isActive = false
             case (false, nil):
-                childHeightConstraint = innerChild.heightAnchor.constraint(
-                    equalTo: child.heightAnchor)
+                childHeightConstraint = child.view.heightAnchor.constraint(
+                    equalTo: scrollView.heightAnchor)
                 fallthrough
             case (false, false):
                 childHeightConstraint!.isActive = true
@@ -42,68 +45,67 @@ final class ScrollWidget: WrapperWidget<UIScrollView> {
             case (true, true):
                 childWidthConstraint!.isActive = false
             case (false, nil):
-                childWidthConstraint = innerChild.widthAnchor.constraint(equalTo: child.widthAnchor)
+            childWidthConstraint = child.view.widthAnchor.constraint(equalTo: scrollView.widthAnchor)
                 fallthrough
             case (false, false):
                 childWidthConstraint!.isActive = true
             default:
                 break
         }
 
-        child.showsVerticalScrollIndicator = hasVerticalScrollBar
-        child.showsHorizontalScrollIndicator = hasHorizontalScrollBar
+        scrollView.showsVerticalScrollIndicator = hasVerticalScrollBar
+        scrollView.showsHorizontalScrollIndicator = hasHorizontalScrollBar
     }
 }
 
 extension UIKitBackend {
     public func createContainer() -> Widget {
-        BaseWidget()
+        BaseViewWidget()
     }
 
     public func removeAllChildren(of container: Widget) {
-        container.subviews.forEach { $0.removeFromSuperview() }
+        container.childWidgets.forEach { $0.removeFromParentWidget() }
     }
 
     public func addChild(_ child: Widget, to container: Widget) {
-        container.addSubview(child)
+        child.add(toWidget: container)
     }
 
     public func setPosition(
         ofChildAt index: Int,
         in container: Widget,
         to position: SIMD2<Int>
     ) {
-        guard index < container.subviews.count else {
+        guard index < container.childWidgets.count else {
             assertionFailure("Attempting to set position of nonexistent subview")
             return
         }
 
-        let child = container.subviews[index] as! BaseWidget
+        let child = container.childWidgets[index]
         child.x = position.x
         child.y = position.y
     }
 
     public func removeChild(_ child: Widget, from container: Widget) {
-        assert(child.isDescendant(of: container))
-        child.removeFromSuperview()
+        assert(child.view.isDescendant(of: container.view))
+        child.removeFromParentWidget()
     }
 
     public func createColorableRectangle() -> Widget {
-        BaseWidget()
+        BaseViewWidget()
     }
 
     public func setColor(ofColorableRectangle widget: Widget, to color: Color) {
-        widget.backgroundColor = color.uiColor
+        widget.view.backgroundColor = color.uiColor
     }
 
     public func setCornerRadius(of widget: Widget, to radius: Int) {
-        widget.layer.cornerRadius = CGFloat(radius)
-        widget.layer.masksToBounds = true
-        widget.setNeedsLayout()
+        widget.view.layer.cornerRadius = CGFloat(radius)
+        widget.view.layer.masksToBounds = true
     }
 
     public func naturalSize(of widget: Widget) -> SIMD2<Int> {
-        let size = widget.intrinsicContentSize
+        let size = widget.view.intrinsicContentSize
         return SIMD2(
             Int(size.width.rounded(.awayFromZero)),
             Int(size.height.rounded(.awayFromZero))

Sources/UIKitBackend/UIKitBackend+Container.swift

@@ -103,16 +103,16 @@ final class TextFieldWidget: WrapperWidget<UITextField>, UITextFieldDelegate {
     }
 #endif
 
-final class ClickableWidget: WrapperWidget<BaseWidget> {
+final class ClickableWidget: ContainerWidget {
     private var gestureRecognizer: UITapGestureRecognizer!
     var onClick: (() -> Void)?
 
-    override init(child: BaseWidget) {
+    override init(child: some WidgetProtocol) {
         super.init(child: child)
 
         gestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(viewTouched))
         gestureRecognizer.cancelsTouchesInView = true
-        child.addGestureRecognizer(gestureRecognizer)
+        child.view.addGestureRecognizer(gestureRecognizer)
     }
 
     @objc

Sources/UIKitBackend/UIKitBackend+Control.swift

@@ -1,7 +1,7 @@
 import SwiftCrossUI
 import UIKit
 
-protocol Picker: BaseWidget {
+protocol Picker: WidgetProtocol {
     func setOptions(to options: [String])
     func setChangeHandler(to onChange: @escaping (Int?) -> Void)
     func setSelectedOption(to index: Int?)

Sources/UIKitBackend/UIKitBackend+Picker.swift

@@ -3,6 +3,7 @@ import UIKit
 final class RootViewController: UIViewController {
     unowned var backend: UIKitBackend
     var resizeHandler: ((CGSize) -> Void)?
+    private var childWidget: (any WidgetProtocol)?
 
     init(backend: UIKitBackend) {
         self.backend = backend
@@ -33,13 +34,20 @@ final class RootViewController: UIViewController {
         backend.onTraitCollectionChange?()
     }
 
-    func setChild(to child: UIView) {
-        view.subviews.forEach { $0.removeFromSuperview() }
-        view.addSubview(child)
-
+    func setChild(to child: some WidgetProtocol) {
+        childWidget?.removeFromParentWidget()
+        child.removeFromParentWidget()
+        
+        let childController = child.controller
+        view.addSubview(child.view)
+        if let childController {
+            addChild(childController)
+            childController.didMove(toParent: self)
+        }
+        
         NSLayoutConstraint.activate([
-            child.widthAnchor.constraint(equalTo: view.safeAreaLayoutGuide.widthAnchor),
-            child.heightAnchor.constraint(equalTo: view.safeAreaLayoutGuide.heightAnchor),
+            child.view.widthAnchor.constraint(equalTo: view.safeAreaLayoutGuide.widthAnchor),
+            child.view.heightAnchor.constraint(equalTo: view.safeAreaLayoutGuide.heightAnchor)
         ])
     }
 }
@@ -76,9 +84,8 @@ extension UIKitBackend {
         // of the screen could be obscured (e.g. covered by the notch). In the future we
         // might want to let users decide what to do, but for now, lie and say that the safe
         // area insets aren't even part of the window.
-        // If/when this is updated, ``RootViewController/setChild(to:)``,
-        // ``BaseWidget/updateLeftConstraint()``, and ``BaseWidget/updateTopConstraint()``
-        // will also need to be updated.
+        // If/when this is updated, ``RootViewController`` and ``WidgetProtocolHelpers`` will
+        // also need to be updated.
         let size = window.safeAreaLayoutGuide.layoutFrame.size
         return SIMD2(Int(size.width), Int(size.height))
     }

Sources/UIKitBackend/UIKitBackend+Window.swift

@@ -150,8 +150,8 @@ where Self: UIViewRepresentable {
             )
 
         if !dryRun {
-            representingWidget.width = size.size.x
-            representingWidget.height = size.size.y
+            representingWidget.frame.size.width = CGFloat(size.size.x)
+            representingWidget.frame.size.height = CGFloat(size.size.y)
         }
 
         return ViewUpdateResult.leafView(size: size)
@@ -165,7 +165,7 @@ where Coordinator == Void {
     }
 }
 
-final class RepresentingWidget<Representable: UIViewRepresentable>: BaseWidget {
+final class RepresentingWidget<Representable: UIViewRepresentable>: BaseViewWidget {
     var representable: Representable
     var context: UIViewRepresentableContext<Representable.Coordinator>?