Convert initialization wait

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

@@ -49,6 +49,7 @@
 import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
 import io.flutter.plugin.platform.PlatformView;
+import io.flutter.plugins.googlemaps.Messages.MapsApi;
 import io.flutter.plugins.googlemaps.Messages.MapsInspectorApi;
 import java.io.ByteArrayOutputStream;
 import java.util.ArrayList;
@@ -67,6 +68,7 @@ class GoogleMapController
         DefaultLifecycleObserver,
         GoogleMapListener,
         GoogleMapOptionsSink,
+        Messages.MapsApi,
         MapsInspectorApi,
         MethodChannel.MethodCallHandler,
         OnMapReadyCallback,
@@ -88,7 +90,7 @@ class GoogleMapController
   private boolean buildingsEnabled = true;
   private boolean disposed = false;
   @VisibleForTesting final float density;
-  private MethodChannel.Result mapReadyResult;
+  private @Nullable Messages.VoidResult mapReadyResult;
   private final Context context;
   private final LifecycleProvider lifecycleProvider;
   private final MarkersController markersController;
@@ -125,6 +127,7 @@ class GoogleMapController
     methodChannel =
         new MethodChannel(binaryMessenger, "plugins.flutter.dev/google_maps_android_" + id);
     methodChannel.setMethodCallHandler(this);
+    MapsApi.setUp(binaryMessenger, Integer.toString(id), this);
     MapsInspectorApi.setUp(binaryMessenger, Integer.toString(id), this);
     AssetManager assetManager = context.getAssets();
     this.lifecycleProvider = lifecycleProvider;
@@ -203,7 +206,7 @@ public void onMapReady(@NonNull GoogleMap googleMap) {
     this.googleMap.setBuildingsEnabled(this.buildingsEnabled);
     installInvalidator();
     if (mapReadyResult != null) {
-      mapReadyResult.success(null);
+      mapReadyResult.success();
       mapReadyResult = null;
     }
     setGoogleMapListener(this);
@@ -308,13 +311,6 @@ public void onSurfaceTextureUpdated(@NonNull SurfaceTexture surface) {
   @Override
   public void onMethodCall(MethodCall call, @NonNull MethodChannel.Result result) {
     switch (call.method) {
-      case "map#waitForMap":
-        if (googleMap != null) {
-          result.success(null);
-          return;
-        }
-        mapReadyResult = result;
-        break;
       case "map#update":
         {
           Convert.interpretGoogleMapOptions(call.argument("options"), this);
@@ -602,6 +598,7 @@ public void dispose() {
     }
     disposed = true;
     methodChannel.setMethodCallHandler(null);
+    MapsApi.setUp(binaryMessenger, Integer.toString(id), null);
     MapsInspectorApi.setUp(binaryMessenger, Integer.toString(id), null);
     setGoogleMapListener(null);
     setMarkerCollectionListener(null);
@@ -1016,6 +1013,17 @@ private boolean updateMapStyle(String style) {
     return set;
   }
 
+  /** MapsApi implementation */
+  @Override
+  public void waitForMap(@NonNull Messages.VoidResult result) {
+    if (googleMap == null) {
+      mapReadyResult = result;
+    } else {
+      result.success();
+    }
+  }
+
+  /** MapsInspectorApi implementation */
   @Override
   public @NonNull Boolean areBuildingsEnabled() {
     return googleMap.isBuildingsEnabled();

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

@@ -605,6 +605,87 @@ protected void writeValue(@NonNull ByteArrayOutputStream stream, Object value) {
     }
   }
 
+  /** Asynchronous error handling return type for non-nullable API method returns. */
+  public interface Result<T> {
+    /** Success case callback method for handling returns. */
+    void success(@NonNull T result);
+
+    /** Failure case callback method for handling errors. */
+    void error(@NonNull Throwable error);
+  }
+  /** Asynchronous error handling return type for nullable API method returns. */
+  public interface NullableResult<T> {
+    /** Success case callback method for handling returns. */
+    void success(@Nullable T result);
+
+    /** Failure case callback method for handling errors. */
+    void error(@NonNull Throwable error);
+  }
+  /** Asynchronous error handling return type for void API method returns. */
+  public interface VoidResult {
+    /** Success case callback method for handling returns. */
+    void success();
+
+    /** Failure case callback method for handling errors. */
+    void error(@NonNull Throwable error);
+  }
+  /**
+   * Interface for non-test interactions with the native SDK.
+   *
+   * <p>For test-only state queries, see [MapsInspectorApi].
+   *
+   * <p>Generated interface from Pigeon that represents a handler of messages from Flutter.
+   */
+  public interface MapsApi {
+    /** Returns once the map instance is available. */
+    void waitForMap(@NonNull VoidResult result);
+
+    /** The codec used by MapsApi. */
+    static @NonNull MessageCodec<Object> getCodec() {
+      return PigeonCodec.INSTANCE;
+    }
+    /** Sets up an instance of `MapsApi` to handle messages through the `binaryMessenger`. */
+    static void setUp(@NonNull BinaryMessenger binaryMessenger, @Nullable MapsApi api) {
+      setUp(binaryMessenger, "", api);
+    }
+
+    static void setUp(
+        @NonNull BinaryMessenger binaryMessenger,
+        @NonNull String messageChannelSuffix,
+        @Nullable MapsApi api) {
+      messageChannelSuffix = messageChannelSuffix.isEmpty() ? "" : "." + messageChannelSuffix;
+      {
+        BasicMessageChannel<Object> channel =
+            new BasicMessageChannel<>(
+                binaryMessenger,
+                "dev.flutter.pigeon.google_maps_flutter_android.MapsApi.waitForMap"
+                    + messageChannelSuffix,
+                getCodec());
+        if (api != null) {
+          channel.setMessageHandler(
+              (message, reply) -> {
+                ArrayList<Object> wrapped = new ArrayList<Object>();
+                VoidResult resultCallback =
+                    new VoidResult() {
+                      public void success() {
+                        wrapped.add(0, null);
+                        reply.reply(wrapped);
+                      }
+
+                      public void error(Throwable error) {
+                        ArrayList<Object> wrappedError = wrapError(error);
+                        reply.reply(wrappedError);
+                      }
+                    };
+
+                api.waitForMap(resultCallback);
+              });
+        } else {
+          channel.setMessageHandler(null);
+        }
+      }
+    }
+  }
   /**
    * Inspector API only intended for use in integration tests.
    *

packages/google_maps_flutter/google_maps_flutter_android/lib/src/google_maps_flutter_android.dart

@@ -68,6 +68,8 @@ class GoogleMapsFlutterAndroid extends GoogleMapsFlutterPlatform {
   // Every method call passes the int mapId
   final Map<int, MethodChannel> _channels = <int, MethodChannel>{};
 
+  final Map<int, MapsApi> _hostMaps = <int, MapsApi>{};
+
   /// Accesses the MethodChannel associated to the passed mapId.
   MethodChannel _channel(int mapId) {
     final MethodChannel? channel = _channels[mapId];
@@ -77,6 +79,15 @@ class GoogleMapsFlutterAndroid extends GoogleMapsFlutterPlatform {
     return channel;
   }
 
+  /// Accesses the MapsApi associated to the passed mapId.
+  MapsApi _hostApi(int mapId) {
+    final MapsApi? api = _hostMaps[mapId];
+    if (api == null) {
+      throw UnknownMapIDError(mapId);
+    }
+    return api;
+  }
+
   // Keep a collection of mapId to a map of TileOverlays.
   final Map<int, Map<TileOverlayId, TileOverlay>> _tileOverlays =
       <int, Map<TileOverlayId, TileOverlay>>{};
@@ -94,10 +105,23 @@ class GoogleMapsFlutterAndroid extends GoogleMapsFlutterPlatform {
     return channel;
   }
 
+  /// Returns the API instance for [mapId], creating it if it doesn't already
+  /// exist.
+  @visibleForTesting
+  MapsApi ensureApiInitialized(int mapId) {
+    MapsApi? api = _hostMaps[mapId];
+    if (api == null) {
+      api = MapsApi(messageChannelSuffix: mapId.toString());
+      _hostMaps[mapId] = api;
+    }
+    return api;
+  }
+
   @override
   Future<void> init(int mapId) {
-    final MethodChannel channel = ensureChannelInitialized(mapId);
-    return channel.invokeMethod<void>('map#waitForMap');
+    ensureChannelInitialized(mapId);
+    final MapsApi hostApi = ensureApiInitialized(mapId);
+    return hostApi.waitForMap();
   }
 
   @override

packages/google_maps_flutter/google_maps_flutter_android/lib/src/messages.g.dart

@@ -216,6 +216,49 @@ class _PigeonCodec extends StandardMessageCodec {
   }
 }
 
+/// Interface for non-test interactions with the native SDK.
+///
+/// For test-only state queries, see [MapsInspectorApi].
+class MapsApi {
+  /// Constructor for [MapsApi].  The [binaryMessenger] named argument is
+  /// available for dependency injection.  If it is left null, the default
+  /// BinaryMessenger will be used which routes to the host platform.
+  MapsApi({BinaryMessenger? binaryMessenger, String messageChannelSuffix = ''})
+      : __pigeon_binaryMessenger = binaryMessenger,
+        __pigeon_messageChannelSuffix =
+            messageChannelSuffix.isNotEmpty ? '.$messageChannelSuffix' : '';
+  final BinaryMessenger? __pigeon_binaryMessenger;
+
+  static const MessageCodec<Object?> pigeonChannelCodec = _PigeonCodec();
+
+  final String __pigeon_messageChannelSuffix;
+
+  /// Returns once the map instance is available.
+  Future<void> waitForMap() async {
+    final String __pigeon_channelName =
+        'dev.flutter.pigeon.google_maps_flutter_android.MapsApi.waitForMap$__pigeon_messageChannelSuffix';
+    final BasicMessageChannel<Object?> __pigeon_channel =
+        BasicMessageChannel<Object?>(
+      __pigeon_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: __pigeon_binaryMessenger,
+    );
+    final List<Object?>? __pigeon_replyList =
+        await __pigeon_channel.send(null) as List<Object?>?;
+    if (__pigeon_replyList == null) {
+      throw _createConnectionError(__pigeon_channelName);
+    } else if (__pigeon_replyList.length > 1) {
+      throw PlatformException(
+        code: __pigeon_replyList[0]! as String,
+        message: __pigeon_replyList[1] as String?,
+        details: __pigeon_replyList[2],
+      );
+    } else {
+      return;
+    }
+  }
+}
+
 /// Inspector API only intended for use in integration tests.
 class MapsInspectorApi {
   /// Constructor for [MapsInspectorApi].  The [binaryMessenger] named argument is

packages/google_maps_flutter/google_maps_flutter_android/pigeons/messages.dart

@@ -68,6 +68,16 @@ class PlatformZoomRange {
   final double max;
 }
 
+/// Interface for non-test interactions with the native SDK.
+///
+/// For test-only state queries, see [MapsInspectorApi].
+@HostApi()
+abstract class MapsApi {
+  /// Returns once the map instance is available.
+  @async
+  void waitForMap();
+}
+
 /// Inspector API only intended for use in integration tests.
 @HostApi()
 abstract class MapsInspectorApi {