Release the map view and the controller when the map leaves the composition

src/main/java/com/mapconductor/mapbox/MapboxMapView.kt

@@ -11,9 +11,12 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
 import androidx.lifecycle.compose.LocalLifecycleOwner
+import androidx.lifecycle.findViewTreeLifecycleOwner
+import androidx.lifecycle.setViewTreeLifecycleOwner
 import com.mapbox.maps.MapInitOptions
 import com.mapbox.maps.MapView
 import com.mapconductor.compose.map.MapViewBase
+import com.mapconductor.compose.map.MapViewLifecycleOwner
 import com.mapconductor.core.OnCameraMoveHandler
 import com.mapconductor.core.OnMapEventHandler
 import com.mapconductor.core.OnMapLoadedHandler
@@ -58,7 +61,6 @@ import android.annotation.SuppressLint
 import android.app.Activity
 import android.content.Context
 import android.content.ContextWrapper
-import android.view.ViewGroup
 
 @SuppressLint("Lifecycle")
 @Composable
@@ -117,6 +119,12 @@ fun MapboxMapView(
                 )
 
             MapView(context, mapOptions).also {
+                // Mapbox's lifecycle plugin follows the view tree's lifecycle and
+                // only lets go of the MapView (component callbacks, observers)
+                // when that lifecycle is destroyed. With the Activity's, every
+                // MapView the user switched away from would stay until the
+                // Activity goes, so it gets one of its own; see onDestroyMapView.
+                it.setViewTreeLifecycleOwner(MapViewLifecycleOwner(lifecycle))
                 it.onStart()
             }
         },
@@ -221,27 +229,26 @@ fun MapboxMapView(
                             // Do not call here to keep the MapView instance
                             // holderRef.value?.mapView?.onPause()
                         }
-
-                        @SuppressLint("Lifecycle")
-                        override fun onDestroy(owner: LifecycleOwner) {
-                            val currentHolder = holderRef.value
-                            if (currentHolder != null) {
-                                val activity = context.findActivity()
-                                if (activity?.isChangingConfigurations == true) {
-                                    (currentHolder.mapView.parent as? ViewGroup)?.removeView(currentHolder.mapView)
-                                } else {
-                                    // Ensure these calls are safe if mapView might be null or already destroyed
-                                    currentHolder.mapView.onDestroy()
-                                }
-                            }
-                        }
                     }
                 lifecycle.addObserver(observer)
                 onDispose {
                     lifecycle.removeObserver(observer)
                 }
             }
         },
+        // Ending the MapView's own lifecycle has the lifecycle plugin stop and
+        // destroy it and unregister what it registered. A MapView left alive
+        // keeps its renderer and, through its listeners, the controller with
+        // every overlay.
+        onDestroyMapView = { mapView ->
+            val owner = mapView.findViewTreeLifecycleOwner() as? MapViewLifecycleOwner
+            if (owner != null) {
+                owner.destroy()
+            } else {
+                mapView.onStop()
+                mapView.onDestroy()
+            }
+        },
     )
 }
 

src/main/java/com/mapconductor/mapbox/MapboxViewStateImpl.kt

@@ -23,7 +23,10 @@ class MapboxViewState(
     cameraPosition: MapCameraPosition = MapCameraPosition.Default,
 ) : MapViewState<MapboxDesignType>(cameraPosition),
     MapboxViewStateInterface {
-    private var controller: MapboxMapViewControllerInterface? = null
+    // Read through the base so that letting go of the controller there (MapViewBase
+    // does it when the map is torn down) leaves nothing behind here.
+    private val controller: MapboxMapViewControllerInterface?
+        get() = attachedMapController as? MapboxMapViewControllerInterface
 
     private var _mapDesignType: MapboxDesignType = mapDesignType
 
@@ -35,7 +38,6 @@ class MapboxViewState(
         get() = _mapDesignType
 
     internal fun setController(controller: MapboxMapViewControllerInterface) {
-        this.controller = controller
         attachController(controller)
     }
 

src/main/java/com/mapconductor/mapbox/polygon/MapboxPolygonConductor.kt

@@ -129,7 +129,10 @@ class MapboxPolygonConductor(
         }
 
     override fun destroy() {
-        // No native resources to clean up for polygons
+        // A destroyed conductor can still be referenced (by its map controller,
+        // or a state that has not let go yet); without this it keeps every entity.
+        polygonOverlay.polygonManager.clear()
+        polylineOverlay.polylineManager.clear()
     }
 }