Replace KVO for measurer with bounds observer

modules/keyboard-avoiding-view/ios/BoundsObservableView.swift

@@ -0,0 +1,13 @@
+public class BoundsObservableView: UIView {
+  public weak var boundsDelegate: ViewBoundsObserving?
+  private var previousBounds: CGRect = .zero
+
+  public override func layoutSubviews() {
+    if bounds != previousBounds {
+      boundsDelegate?.boundsDidChange(self, from: previousBounds)
+      previousBounds = bounds
+    }
+
+    super.layoutSubviews()
+  }
+}

modules/keyboard-avoiding-view/ios/KeyboardAvoidingView.swift

@@ -2,11 +2,10 @@ import ExpoModulesCore
 
 // This view will be used as a native component. Make sure to inherit from `ExpoView`
 // to apply the proper styling (e.g. border radius and shadows).
-class KeyboardAvoidingView: ExpoView, UIGestureRecognizerDelegate {
-  private let measurer = UIView()
+class KeyboardAvoidingView: ExpoView, UIGestureRecognizerDelegate, ViewBoundsObserving {
+  private let measurer = BoundsObservableView()
   private let container = UIView()
   private var scrollView: ScrollViewWrapper?
-  private var measurerHasObserver = false
   private var isScrollViewPanning = false
   private lazy var containerBottomAnchorConstraint: NSLayoutConstraint = {
     return container.bottomAnchor.constraint(equalTo: bottomAnchor)
@@ -21,6 +20,7 @@ class KeyboardAvoidingView: ExpoView, UIGestureRecognizerDelegate {
     addSubview(measurer)
     measurer.translatesAutoresizingMaskIntoConstraints = false
     measurer.isHidden = true
+    measurer.boundsDelegate = self
 
     addSubview(container)
     container.translatesAutoresizingMaskIntoConstraints = false
@@ -72,12 +72,6 @@ class KeyboardAvoidingView: ExpoView, UIGestureRecognizerDelegate {
     }
   }
 
-  deinit {
-    if measurerHasObserver {
-      measurer.removeObserver(self, forKeyPath: "center")
-    }
-  }
-
   @objc private func keyboardWillShow(_ notification: Notification) {
     guard notification.isLocalKeyboard else { return }
 
@@ -87,11 +81,6 @@ class KeyboardAvoidingView: ExpoView, UIGestureRecognizerDelegate {
   @objc private func keyboardDidShow(_ notification: Notification) {
     guard notification.isLocalKeyboard else { return }
 
-    // FIXME: don't use KVO
-    if !measurerHasObserver {
-      measurer.addObserver(self, forKeyPath: "center", options: .new, context: nil)
-      measurerHasObserver = true
-    }
     isKeyboardShown = true
   }
 
@@ -128,28 +117,16 @@ class KeyboardAvoidingView: ExpoView, UIGestureRecognizerDelegate {
   @objc private func keyboardWillHide(_ notification: Notification) {
     guard notification.isLocalKeyboard else { return }
 
-    if measurerHasObserver {
-      measurer.removeObserver(self, forKeyPath: "center")
-      measurerHasObserver = false
-    }
     isKeyboardShown = false
     updateInsets(notification, closing: true)
   }
 
-  @objc override public func observeValue(
-    forKeyPath keyPath: String?,
-    of object: Any?,
-    change: [NSKeyValueChangeKey: Any]?,
-    context _: UnsafeMutableRawPointer?
-  ) {
-    if keyPath == "center", object as? NSObject == measurer {
-      if !isScrollViewPanning {
-        return
-      }
-      self.scrollView?.setInsetsFromKeyboardHeight(measurer.frame.height)
-      self.containerBottomAnchorConstraint.constant = -measurer.frame.height
-      self.layoutIfNeeded()
-    }
+  func boundsDidChange(_ view: BoundsObservableView, from previousBounds: CGRect) {
+    guard isKeyboardShown && isScrollViewPanning else { return }
+
+    self.scrollView?.setInsetsFromKeyboardHeight(view.bounds.height)
+    self.containerBottomAnchorConstraint.constant = -view.bounds.height
+    self.layoutIfNeeded()
   }
 
   @objc func scrollViewPanned(gesture: UIPanGestureRecognizer) {

modules/keyboard-avoiding-view/ios/ViewBoundsObserving.swift

@@ -0,0 +1,3 @@
+public protocol ViewBoundsObserving: AnyObject {
+  func boundsDidChange(_ view: BoundsObservableView, from previousBounds: CGRect)
+}