Fix issue where markers aren't updated in Flutter v3.0.0

Author: Emmanuel Garcia

packages/google_maps_flutter/google_maps_flutter/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 2.1.6
 
+* Fixes issue in Flutter v3.0.0 where markers aren't updated.
 * Fixes iOS native unit tests on M1 devices.
 * Minor fixes for new analysis options.
 

packages/google_maps_flutter/google_maps_flutter/android/src/main/java/io/flutter/plugins/googlemaps/GoogleMapController.java

@@ -12,6 +12,7 @@
 import android.graphics.Point;
 import android.os.Bundle;
 import android.util.Log;
+import android.view.Choreographer;
 import android.view.View;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -151,6 +152,17 @@ public void onMapReady(GoogleMap googleMap) {
     updateInitialTileOverlays();
   }
 
+  private static void postFrameCallback(Runnable f) {
+    Choreographer.getInstance().postFrameCallback(
+      new Choreographer.FrameCallback() {
+        @Override
+        public void doFrame(long frameTimeNanos) {
+          f.run();
+        }
+      }
+    );
+  }
+
   @Override
   public void onMethodCall(MethodCall call, MethodChannel.Result result) {
     switch (call.method) {
@@ -250,6 +262,27 @@ public void onSnapshotReady(Bitmap bitmap) {
           markersController.changeMarkers(markersToChange);
           List<Object> markerIdsToRemove = call.argument("markerIdsToRemove");
           markersController.removeMarkers(markerIdsToRemove);
+
+          // gmscore GL renderer uses a TextureView.
+          // Android platform views that are displayed as a texture after Flutter v3.0.0.
+          // require that the view hierarchy is notified after all drawing operations have been flushed.
+          // Since the GL renderer doesn't use standard Android views, and instead uses TextureView,
+          // we notify the view hierarchy by invalidating the view.
+          // Unfortunately, when OnMapLoadedCallback is fired, the texture may not have been updated yet.
+          // To workaround this limitation, wait two frames.
+          // This ensures that at least the frame budget (16.66ms at 60hz) have passed since the
+          // drawing operation was issued.
+          googleMap.setOnMapLoadedCallback(new GoogleMap.OnMapLoadedCallback() {
+            @Override
+            public void onMapLoaded() {
+              postFrameCallback(() -> {
+                postFrameCallback(() -> {
+                  mapView.invalidate();
+                });
+              });
+            }
+          });
+
           result.success(null);
           break;
         }

packages/google_maps_flutter/google_maps_flutter/pubspec.yaml

@@ -2,7 +2,7 @@ name: google_maps_flutter
 description: A Flutter plugin for integrating Google Maps in iOS and Android applications.
 repository: https://github.com/flutter/plugins/tree/main/packages/google_maps_flutter/google_maps_flutter
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+maps%22
-version: 2.1.5
+version: 2.1.6
 
 environment:
   sdk: ">=2.14.0 <3.0.0"