Rudimentary autocomplete focus

App/Titlebar and URL Bar/URLBar.swift

@@ -7,13 +7,29 @@
 
 import UIKit
 
+protocol URLBarDelegate: AnyObject
+{
+    func urlBarRequestedFocusEscape(_ urlBar: URLBar)
+}
+
+class TextFieldWithKeyCommands: UITextField
+{
+    internal var _keyCommands: [UIKeyCommand]? = []
+    override var keyCommands: [UIKeyCommand]? {
+        get { _keyCommands }
+        set { _keyCommands = newValue }
+    }
+}
+
 class URLBar: ReliefButton
 {
-    let textField = UITextField(frame: .zero)
+    let textField = TextFieldWithKeyCommands(frame: .zero)
     let refreshButton = UIButton(frame: .zero)
     let errorButton = UIButton(frame: .zero)
     let documentButton = UIButton(frame: .zero)
     
+    weak var delegate: URLBarDelegate?
+    
     public enum LoadProgress {
         case complete
         case loading(progress: Double)
@@ -57,6 +73,9 @@ class URLBar: ReliefButton
             // Mask view visibility is affected by editing state.
             self.layoutSubviews()
         }), for: [ .editingDidBegin, .editingDidEnd ])
+        textField.keyCommands = [
+            UIKeyCommand(action: #selector(Self.downKeyPressed), input: UIKeyCommand.inputDownArrow)
+        ]
         addSubview(textField)
         
         textField.addAction(.init(handler: { [textField, refreshButton] _ in
@@ -89,6 +108,11 @@ class URLBar: ReliefButton
         fatalError("init(coder:) has not been implemented")
     }
     
+    @objc
+    private func downKeyPressed(_ sender: Any?) {
+        self.delegate?.urlBarRequestedFocusEscape(self)
+    }
+    
     private func updateProgressIndicator() {
         setErrorButtonAnimating(false)