fix null pointer in ArcgsMapView

Author: JulianBissekkou

arcgis_map_sdk_android/android/build.gradle

@@ -2,14 +2,14 @@ group 'dev.fluttercommunity.arcgis_map_sdk_android'
 version '1.0-SNAPSHOT'
 
 buildscript {
-    ext.kotlin_version = '1.6.10'
+    ext.kotlin_version = '1.9.0'
     repositories {
         google()
         mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.1.3'
+        classpath 'com.android.tools.build:gradle:8.3.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -29,8 +29,7 @@ apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion 31
-
+    compileSdkVersion 34
 
     // Conditional for compatibility with AGP <4.2.
     if (project.android.hasProperty("namespace")) {

arcgis_map_sdk_android/android/gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,6 @@
+#Thu Oct 24 09:10:14 CEST 2024
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

arcgis_map_sdk_android/android/src/main/kotlin/dev/fluttercommunity/arcgis_map_sdk_android/ArcgisMapView.kt

@@ -101,20 +101,24 @@ internal class ArcgisMapView(
         mapView.graphicsOverlays.add(defaultGraphicsOverlay)
 
         mapView.addMapScaleChangedListener {
-            val zoomLevel = getZoomLevel(mapView)
+            if(mapView.mapScale.isNaN()) return@addMapScaleChangedListener
 
+            val zoomLevel = getZoomLevel(mapView)
             zoomStreamHandler.addZoom(zoomLevel)
         }
+
         mapView.addViewpointChangedListener {
-            val center = mapView.visibleArea.extent.center
-            val wgs84Center =
-                GeometryEngine.project(center, SpatialReferences.getWgs84()) as Point
-            centerPositionStreamHandler.add(
-                LatLng(
-                    longitude = wgs84Center.x,
-                    latitude = wgs84Center.y
-                )
-            )
+            // The viewpoint listener is executed async which means that the map
+            // can be altered when this is called. If we reload the map or dispose the map
+            // we don't have a visibleArea or an extent which would throw null pointer in this case.
+            val center = mapView.visibleArea?.extent?.center ?: return@addViewpointChangedListener
+            val wgs84Center = GeometryEngine.project(center, SpatialReferences.getWgs84()) as? Point
+
+            val latLng = wgs84Center?.let {
+                LatLng(longitude = it.x,latitude = it.y)
+            } ?: return@addViewpointChangedListener
+
+            centerPositionStreamHandler.add(latLng)
         }
 
         val viewPoint = Viewpoint(