Introspect fails inside LazyVStack

[hugehoge]

Environment

• Xcode 13.2.1
• iOS 15.2 simulator
• Introspect 0.1.4

Reproduction

Code

struct ContentView: View {
  var body: some View {
    ScrollView {
      LazyVStack {
        ForEach(0..<20) { index in
          Color(hue: Double(index * 17 % 100) / 100, saturation: 0.5, brightness: 1.0)
            .frame(height: UIScreen.main.bounds.height / 10)
        }

        TextField("Placholder", text: .constant(""))
          .introspectTextField { view in
            view.layer.backgroundColor = UIColor.red.cgColor
          }
          .padding()

        Toggle("Toggle", isOn: .constant(true))
          .introspectSwitch { view in
            view.thumbTintColor = .red
          }
          .padding()
      }
    }
  }
}

Result

Result	If use VStack
Reproduction.mp4	UseVStack.mp4

[hugehoge]

It seems that the following workaround would not work well in LazyVStack.

https://github.com/siteline/SwiftUI-Introspect/blob/72a509c93166540c0adf8323fd2652daade7f9f6/Introspect/UIKitIntrospectionView.swift#L47-L62

An alternative workaround I tried is below:

--- a/Introspect/UIKitIntrospectionView.swift
+++ b/Introspect/UIKitIntrospectionView.swift
@@ -5,6 +5,8 @@ import SwiftUI
 /// Introspection UIView that is inserted alongside the target view.
 @available(iOS 13.0, *)
 public class IntrospectionUIView: UIView {
+
+    var moveToWindowHandler: (() -> Void)?

     required init() {
         super.init(frame: .zero)
@@ -16,6 +18,11 @@ public class IntrospectionUIView: UIView {
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
+
+    override public func didMoveToWindow() {
+        super.didMoveToWindow()
+        moveToWindowHandler?()
+    }
 }

 /// Introspection View that is injected into the UIKit hierarchy alongside the target view.
@@ -53,7 +60,7 @@ public struct UIKitIntrospectionView<TargetViewType: UIView>: UIViewRepresentabl
         _ uiView: IntrospectionUIView,
         context: UIViewRepresentableContext<UIKitIntrospectionView>
     ) {
-        DispatchQueue.main.async {
+        uiView.moveToWindowHandler = {
             guard let targetView = self.selector(uiView) else {
                 return
             }

Use UIView.didMoveToWindow instead of DispatchQueue.main.async to wait for the introspection view to be inserted to the hierarchy.

In my quick check, it would fix an issue that the use of introspect inside LazyVStack.

However, it makes some existing test cases failed and may cause many other effects.

[plaps153]

Same here!

[hugehoge]

UPDATE

Leaving DispatchQueue.main.async, the existing tests will be passed.

@@ -53,11 +70,13 @@ public struct UIKitIntrospectionView<TargetViewType: UIView>: UIViewRepresentabl
         _ uiView: IntrospectionUIView,
         context: UIViewRepresentableContext<UIKitIntrospectionView>
     ) {
-        DispatchQueue.main.async {
-            guard let targetView = self.selector(uiView) else {
-                return
+        uiView.moveToWindowHandler = {
+            DispatchQueue.main.async {
+                guard let targetView = self.selector(uiView) else {
+                    return
+                }
+                self.customize(targetView)
             }
-            self.customize(targetView)
         }
     }
 }

[davdroman]

Apparently fixed in #153. Will tag a release soon.