fix early release of KVO observer

Author: Alex009

gradle/libs.versions.toml

@@ -1,7 +1,7 @@
 [versions]
 kotlinVersion = "1.8.10"
 
-mokoWidgetsVersion = "0.2.3"
+mokoWidgetsVersion = "0.2.4"
 mokoResourcesVersion = "0.21.2"
 mokoMvvmVersion = "0.16.0"
 mokoFieldsVersion = "0.12.0"

widgets/build.gradle.kts

@@ -38,8 +38,8 @@ kotlin {
             this as org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
 
             compilations.getByName("main") {
-                val pluralizedString by cinterops.creating {
-                    defFile(project.file("src/iosMain/def/objcAddtition.def"))
+                val objcAddition by cinterops.creating {
+                    defFile(project.file("src/iosMain/def/objcAddition.def"))
                 }
             }
         }

widgets/src/iosMain/def/objcAddtition.def widgets/src/iosMain/def/objcAddition.defwidgets/src/iosMain/def/objcAddtition.def renamed to widgets/src/iosMain/def/objcAddition.def

@@ -20,6 +20,10 @@ void setAssociatedObject(id object, id value) {
   return objc_setAssociatedObject(object, &kAssociatedObjectKey, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 }
 
+void setAssociatedObjectWithKey(id object, NSValue* key, id value) {
+  return objc_setAssociatedObject(object, key.pointerValue, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+}
+
 NSArray* cgColors(NSArray<UIColor*>* uiColors) {
   NSMutableArray* result = [NSMutableArray arrayWithCapacity: uiColors.count];
   for(int i = 0;i < uiColors.count;i++) {

widgets/src/iosMain/kotlin/dev/icerock/moko/widgets/core/utils/UIControlExt.kt

@@ -5,12 +5,18 @@
 package dev.icerock.moko.widgets.core.utils
 
 import dev.icerock.moko.widgets.objc.KeyValueObserverProtocol
+import dev.icerock.moko.widgets.objc.setAssociatedObjectWithKey
 import kotlinx.cinterop.COpaquePointer
+import kotlinx.cinterop.ExportObjCClass
 import kotlinx.cinterop.ObjCAction
 import kotlinx.cinterop.cstr
 import platform.Foundation.NSKeyValueObservingOptionNew
 import platform.Foundation.NSSelectorFromString
+import platform.Foundation.NSString
+import platform.Foundation.NSValue
+import platform.Foundation.UTF8String
 import platform.Foundation.addObserver
+import platform.Foundation.valueWithPointer
 import platform.UIKit.UIControl
 import platform.UIKit.UIControlEvents
 import platform.UIKit.UIGestureRecognizer
@@ -58,24 +64,28 @@ fun UIGestureRecognizer.setHandler(action: () -> Unit) {
     )
 }
 
+private val keys = mutableMapOf<String, NSValue>()
+
 fun <V : UIView, CTX> V.observeKeyChanges(
     keyPath: String,
     context: CTX,
     action: (V, CTX) -> Unit
 ) {
-    val ref: WeakReference<V> = WeakReference(this)
-
-    val target = ObserverObject {
-        val strongRef: V = ref.get() ?: return@ObserverObject
+    val target: ObserverObject<V> = ObserverObject(this) {
+        action(this, context)
+    }
 
-        action(strongRef, context)
+    val keyString = "observeKeyChanges-$keyPath"
+    val key: NSValue = keys[keyString] ?: let {
+        NSValue.valueWithPointer((keyString as NSString).UTF8String)
+    }.also {
+        keys[keyString] = it
     }
 
-    objc_setAssociatedObject(
+    setAssociatedObjectWithKey(
         `object` = this,
-        key = "observeKeyChanges-$keyPath".cstr,
-        value = target,
-        policy = OBJC_ASSOCIATION_RETAIN
+        key = key,
+        value = target
     )
 
     this.addObserver(
@@ -86,17 +96,21 @@ fun <V : UIView, CTX> V.observeKeyChanges(
     )
 }
 
-private class ObserverObject(
-    private val lambda: () -> Unit
+@ExportObjCClass
+private class ObserverObject<T : Any>(
+    ref: T,
+    private val lambda: T.() -> Unit
 ) : NSObject(), KeyValueObserverProtocol {
+    private val ref: WeakReference<T> = WeakReference(ref)
 
     override fun observeValueForKeyPath(
         keyPath: String?,
         ofObject: Any?,
         change: Map<Any?, *>?,
         context: COpaquePointer?
     ) {
-        lambda()
+        val strongRef: T = ref.get() ?: return
+        lambda.invoke(strongRef)
     }
 }