cs/Using gesture detector (#327)

* update logics using interaction gesture detector

* review update

Author: changanxian

lib/samples/match_viewpoint_of_geo_views/README.md

@@ -14,7 +14,7 @@ Interact with the MapView or SceneView by zooming or panning. The other MapView
 
 ## How it works
 
-1. Wire up the `onViewpointChanged` and `onNavigationChanged` event handlers for both geo views.
+1. Wire up the `onViewpointChanged` event handlers for both geo views.
 2. In each event handler, get the current viewpoint from the geo view that is being interacted with and then set the viewpoint of the other geo view to the same value.
 3. Note: The reason for setting the viewpoints in multiple event handlers is to account for different types of interactions that can occur (ie. single click pan -vs- continuous pan, single click zoom in -vs- mouse scroll wheel zoom, etc.).
 

lib/samples/match_viewpoint_of_geo_views/match_viewpoint_of_geo_views.dart

@@ -33,23 +33,19 @@ class _MatchViewpointOfGeoViewsState extends State<MatchViewpointOfGeoViews>
   final _mapViewController = ArcGISMapView.createController();
   // A controller for the scene view.
   final _sceneViewController = ArcGISSceneView.createController();
-  // Viewpoint for the map view.
-  Viewpoint? _mapViewViewpoint;
-  // Viewpoint for the scene view.
-  Viewpoint? _sceneViewViewpoint;
-  // A flag to indicate if the map view is currently navigating.
-  bool _isMapViewNavigation = false;
-  // Stream subscriptions for viewpoint and navigation changes.
+  // A flag to indicate if the map view is currently interacting.
+  bool _isMapViewInteraction = false;
+  // A flag to indicate if the scene view is currently interacting.
+  bool _isSceneViewInteraction = false;
+  // Stream subscriptions for viewpoint changes.
   late StreamSubscription _mapViewViewpointChangedSubscription;
-  late StreamSubscription _mapViewNavigationChangedSubscription;
   late StreamSubscription _sceneViewViewpointChangedSubscription;
   // A flag for when the map view is ready and controls can be used.
   var _ready = false;
 
   @override
   void dispose() {
     _mapViewViewpointChangedSubscription.cancel();
-    _mapViewNavigationChangedSubscription.cancel();
     _sceneViewViewpointChangedSubscription.cancel();
     super.dispose();
   }
@@ -83,16 +79,39 @@ class _MatchViewpointOfGeoViewsState extends State<MatchViewpointOfGeoViews>
     return [
       // Add a map view to the widget tree and set a controller.
       Expanded(
-        child: ArcGISMapView(
-          controllerProvider: () => _mapViewController,
-          onMapViewReady: onMapViewReady,
+        child: GestureDetector(
+          behavior: HitTestBehavior.translucent,
+          onTapDown: (_) => setState(() {
+            _isMapViewInteraction = true;
+            _isSceneViewInteraction = false;
+          }),
+          onDoubleTapDown: (_) => setState(() {
+            _isMapViewInteraction = true;
+            _isSceneViewInteraction = false;
+          }),
+          child: ArcGISMapView(
+            controllerProvider: () => _mapViewController,
+            onMapViewReady: onMapViewReady,
+          ),
         ),
       ),
       // Add a scene view to the widget tree and set a controller.
       Expanded(
-        child: ArcGISSceneView(
-          controllerProvider: () => _sceneViewController,
-          onSceneViewReady: onSceneViewReady,
+        child: GestureDetector(
+          behavior: HitTestBehavior.translucent,
+          onDoubleTapDown: (_) => setState(() {
+            _isMapViewInteraction = false;
+            _isSceneViewInteraction = true;
+          }),
+          onTapDown: (_) => setState(() {
+            _isMapViewInteraction = false;
+            _isSceneViewInteraction = true;
+          }),
+
+          child: ArcGISSceneView(
+            controllerProvider: () => _sceneViewController,
+            onSceneViewReady: onSceneViewReady,
+          ),
         ),
       ),
     ];
@@ -104,21 +123,14 @@ class _MatchViewpointOfGeoViewsState extends State<MatchViewpointOfGeoViews>
     final map = ArcGISMap.withBasemapStyle(BasemapStyle.arcGISImagery);
     _mapViewController.arcGISMap = map;
 
-    // Listen for navigation changes in the map view.
-    _mapViewNavigationChangedSubscription = _mapViewController
-        .onNavigationChanged
-        .listen((isNavigating) {
-          _isMapViewNavigation = isNavigating;
-        });
-
     // Listen for viewpoint changes in the map view.
     _mapViewViewpointChangedSubscription = _mapViewController.onViewpointChanged
         .listen((_) {
-          _mapViewViewpoint = _mapViewController.getCurrentViewpoint(
-            ViewpointType.centerAndScale,
-          );
-          if (_isMapViewNavigation) {
-            _sceneViewController.setViewpoint(_mapViewViewpoint!);
+          if (_isMapViewInteraction) {
+            final mapViewViewpoint = _mapViewController.getCurrentViewpoint(
+              ViewpointType.centerAndScale,
+            );
+            _sceneViewController.setViewpoint(mapViewViewpoint!);
           }
         });
 
@@ -137,15 +149,14 @@ class _MatchViewpointOfGeoViewsState extends State<MatchViewpointOfGeoViews>
     _sceneViewViewpointChangedSubscription = _sceneViewController
         .onViewpointChanged
         .listen((_) {
-          _sceneViewViewpoint = _sceneViewController.getCurrentViewpoint(
-            ViewpointType.centerAndScale,
-          );
-
-          if (!_isMapViewNavigation) {
-            _mapViewController.setViewpoint(_sceneViewViewpoint!);
+          if (_isSceneViewInteraction) {
+            final sceneViewViewpoint = _sceneViewController.getCurrentViewpoint(
+              ViewpointType.centerAndScale,
+            );
+            _mapViewController.setViewpoint(sceneViewViewpoint!);
           }
         });
-    
+
     // Set the ready state variable to true to enable the sample UI.
     setState(() => _ready = true);
   }