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

src/main/java/com/mapconductor/openmobilemaps/OpenMobileMapsMapView.kt

@@ -64,7 +64,10 @@ class OpenMobileMapsViewState(
     cameraPosition: MapCameraPosition = MapCameraPosition.Default,
 ) : MapViewState<OpenMobileMapsMapDesignTypeInterface>(cameraPosition),
     OpenMobileMapsViewStateInterface {
-    private var controller: OpenMobileMapsMapViewController? = 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: OpenMobileMapsMapViewController?
+        get() = attachedMapController as? OpenMobileMapsMapViewController
     private var current: OpenMobileMapsMapDesignTypeInterface = mapDesignType
 
     override var mapDesignType: OpenMobileMapsMapDesignTypeInterface
@@ -75,7 +78,6 @@ class OpenMobileMapsViewState(
         }
 
     internal fun setController(controller: OpenMobileMapsMapViewController) {
-        this.controller = controller
         attachController(controller)
     }
 
@@ -280,6 +282,16 @@ fun OpenMobileMapsMapView(
         },
         style = style,
         onStyleDiagnostics = onStyleDiagnostics,
+        // registerLifecycle() put the MapView on the Activity's lifecycle, and
+        // its own onDestroy() does not take it off again: left there, the
+        // Activity keeps every map the user switched away from (and through
+        // its callbacks the controller with every overlay). Take it off first
+        // so the Activity's ON_DESTROY cannot destroy it a second time.
+        onDestroyMapView = { surface ->
+            lifecycleOwner.lifecycle.removeObserver(surface.mapView)
+            surface.mapView.onPause()
+            surface.mapView.onDestroy()
+        },
         content = content,
     )
 }

src/main/java/com/mapconductor/openmobilemaps/OpenMobileMapsMapViewController.kt

@@ -166,9 +166,17 @@ class OpenMobileMapsMapViewController(
         }
     }
 
+    /**
+     * 地図に挿したタッチリスナー。SDK はネイティブ側から JNI の global 参照で掴むので、
+     * [destroy] で外さないとこのコントローラ（と全オーバーレイ）がプロセスに残る。
+     */
+    private var touchListener: OpenMobileMapsTouchListener? = null
+
     /** SDK のイベントをコアの受け口へ転送する。 */
     fun installListeners() {
-        holder.map.getTouchHandler().insertListener(OpenMobileMapsTouchListener(this), 0)
+        val listener = OpenMobileMapsTouchListener(this)
+        touchListener = listener
+        holder.map.getTouchHandler().insertListener(listener, 0)
         holder.map.getCamera().addListener(cameraListener)
         notifyMapInitialized()
     }
@@ -467,6 +475,8 @@ class OpenMobileMapsMapViewController(
     override fun destroy() {
         cancelCameraAnimation()
         runCatching { holder.map.getCamera().removeListener(cameraListener) }
+        touchListener?.let { listener -> runCatching { holder.map.getTouchHandler().removeListener(listener) } }
+        touchListener = null
         removeDragTouchInterceptor()
         super.destroy()
     }