Allow serving Native ads in AdLoaderAd

Allow the `AdLoaderAd` instance to serve `Native` ads, which are
instances of:

  * `NativeAd` under Android, and
  * `GADNativeAd` under iOS

packages/google_mobile_ads/android/src/main/java/io/flutter/plugins/googlemobileads/AdMessageCodec.java

@@ -68,6 +68,7 @@ class AdMessageCodec extends StandardMessageCodec {
   private static final byte VALUE_AD_MANAGER_AD_VIEW_OPTIONS = (byte) 154;
   private static final byte VALUE_BANNER_PARAMETERS = (byte) 155;
   private static final byte VALUE_CUSTOM_PARAMETERS = (byte) 156;
+  private static final byte VALUE_NATIVE_PARAMETERS = (byte) 157;
 
   @NonNull Context context;
   @NonNull final FlutterAdSize.AdSizeFactory adSizeFactory;
@@ -259,6 +260,12 @@ protected void writeValue(ByteArrayOutputStream stream, Object value) {
       FlutterCustomParameters customParameters = (FlutterCustomParameters) value;
       writeValue(stream, customParameters.formatIds);
       writeValue(stream, customParameters.viewOptions);
+    } else if (value instanceof FlutterNativeParameters) {
+      stream.write(VALUE_NATIVE_PARAMETERS);
+      FlutterNativeParameters nativeParameters = (FlutterNativeParameters) value;
+      writeValue(stream, nativeParameters.factoryId);
+      writeValue(stream, nativeParameters.nativeAdOptions);
+      writeValue(stream, nativeParameters.viewOptions);
     } else {
       super.writeValue(stream, value);
     }
@@ -429,6 +436,11 @@ protected Object readValueOfType(byte type, ByteBuffer buffer) {
         return new FlutterCustomParameters(
             (List<String>) readValueOfType(buffer.get(), buffer),
             (Map<String, Object>) readValueOfType(buffer.get(), buffer));
+      case VALUE_NATIVE_PARAMETERS:
+        return new FlutterNativeParameters(
+            (String) readValueOfType(buffer.get(), buffer),
+            (FlutterNativeAdOptions) readValueOfType(buffer.get(), buffer),
+            (Map<String, Object>) readValueOfType(buffer.get(), buffer));
       default:
         return super.readValueOfType(type, buffer);
     }

packages/google_mobile_ads/android/src/main/java/io/flutter/plugins/googlemobileads/FlutterAdLoader.java

@@ -147,7 +147,8 @@ public void loadAdLoaderAd(
       @NonNull AdListener adListener,
       @NonNull AdRequest request,
       @Nullable FlutterAdLoaderAd.BannerParameters bannerParameters,
-      @Nullable FlutterAdLoaderAd.CustomParameters customParameters) {
+      @Nullable FlutterAdLoaderAd.CustomParameters customParameters,
+      @Nullable FlutterAdLoaderAd.NativeParameters nativeParameters) {
     AdLoader.Builder builder = new AdLoader.Builder(context, adUnitId);
     if (bannerParameters != null) {
       builder = builder.forAdManagerAdView(bannerParameters.listener, bannerParameters.adSizes);
@@ -160,6 +161,12 @@ public void loadAdLoaderAd(
         builder = builder.forCustomFormatAd(formatId, customParameters.listener, null);
       }
     }
+    if (nativeParameters != null) {
+      builder = builder.forNativeAd(nativeParameters.listener);
+      if (nativeParameters.nativeAdOptions != null) {
+        builder = builder.withNativeAdOptions(nativeParameters.nativeAdOptions);
+      }
+    }
     builder.withAdListener(adListener).build().loadAd(request);
   }
 
@@ -169,7 +176,8 @@ public void loadAdManagerAdLoaderAd(
       @NonNull AdListener adListener,
       @NonNull AdManagerAdRequest adManagerAdRequest,
       @Nullable FlutterAdLoaderAd.BannerParameters bannerParameters,
-      @Nullable FlutterAdLoaderAd.CustomParameters customParameters) {
+      @Nullable FlutterAdLoaderAd.CustomParameters customParameters,
+      @Nullable FlutterAdLoaderAd.NativeParameters nativeParameters) {
     AdLoader.Builder builder = new AdLoader.Builder(context, adUnitId);
     if (bannerParameters != null) {
       builder = builder.forAdManagerAdView(bannerParameters.listener, bannerParameters.adSizes);
@@ -182,6 +190,12 @@ public void loadAdManagerAdLoaderAd(
         builder = builder.forCustomFormatAd(formatId, customParameters.listener, null);
       }
     }
+    if (nativeParameters != null) {
+      builder = builder.forNativeAd(nativeParameters.listener);
+      if (nativeParameters.nativeAdOptions != null) {
+        builder = builder.withNativeAdOptions(nativeParameters.nativeAdOptions);
+      }
+    }
     builder.withAdListener(adListener).build().loadAd(adManagerAdRequest);
   }
 }

packages/google_mobile_ads/android/src/main/java/io/flutter/plugins/googlemobileads/FlutterAdLoaderAd.java

@@ -24,18 +24,24 @@
 import com.google.android.gms.ads.admanager.AdManagerAdView;
 import com.google.android.gms.ads.formats.AdManagerAdViewOptions;
 import com.google.android.gms.ads.formats.OnAdManagerAdViewLoadedListener;
+import com.google.android.gms.ads.nativead.NativeAd;
+import com.google.android.gms.ads.nativead.NativeAd.OnNativeAdLoadedListener;
+import com.google.android.gms.ads.nativead.NativeAdOptions;
 import com.google.android.gms.ads.nativead.NativeCustomFormatAd;
 import com.google.android.gms.ads.nativead.NativeCustomFormatAd.OnCustomFormatAdLoadedListener;
 import io.flutter.plugin.platform.PlatformView;
 import io.flutter.plugins.googlemobileads.GoogleMobileAdsPlugin.CustomAdFactory;
+import io.flutter.plugins.googlemobileads.GoogleMobileAdsPlugin.NativeAdFactory;
 import java.util.Map;
 
 /**
  * A central wrapper for {@link AdManagerAdView}, {@link NativeCustomFormatAd} and {@link NativeAd}
  * instances served for a single {@link AdRequest} or {@link AdManagerAdRequest}
  */
 class FlutterAdLoaderAd extends FlutterAd
-    implements OnAdManagerAdViewLoadedListener, OnCustomFormatAdLoadedListener {
+    implements OnAdManagerAdViewLoadedListener,
+        OnCustomFormatAdLoadedListener,
+        OnNativeAdLoadedListener {
   private static final String TAG = "FlutterAdLoaderAd";
 
   @NonNull private final AdInstanceManager manager;
@@ -46,6 +52,7 @@ class FlutterAdLoaderAd extends FlutterAd
   @Nullable private View view;
   @Nullable protected BannerParameters bannerParameters;
   @Nullable protected CustomParameters customParameters;
+  @Nullable protected NativeParameters nativeParameters;
 
   static class Builder {
     @Nullable private AdInstanceManager manager;
@@ -57,6 +64,8 @@ static class Builder {
     @Nullable private FlutterBannerParameters bannerParameters;
     @Nullable private FlutterCustomParameters customParameters;
     @Nullable private Map<String, CustomAdFactory> customFactories;
+    @Nullable private FlutterNativeParameters nativeParameters;
+    @Nullable private Map<String, NativeAdFactory> nativeFactories;
 
     public Builder setId(int id) {
       this.id = id;
@@ -104,6 +113,17 @@ public Builder withAvailableCustomFactories(
       return this;
     }
 
+    public Builder setNative(@Nullable FlutterNativeParameters nativeParameters) {
+      this.nativeParameters = nativeParameters;
+      return this;
+    }
+
+    public Builder withAvailableNativeFactories(
+        @NonNull Map<String, NativeAdFactory> nativeFactories) {
+      this.nativeFactories = nativeFactories;
+      return this;
+    }
+
     FlutterAdLoaderAd build() {
       if (manager == null) {
         throw new IllegalStateException("manager must be provided");
@@ -137,6 +157,12 @@ FlutterAdLoaderAd build() {
                 new FlutterCustomFormatAdLoadedListener(adLoaderAd), customFactories);
       }
 
+      if (nativeParameters != null) {
+        adLoaderAd.nativeParameters =
+            nativeParameters.asNativeParameters(
+                new FlutterNativeAdLoadedListener(adLoaderAd), nativeFactories);
+      }
+
       return adLoaderAd;
     }
   }
@@ -171,6 +197,24 @@ static class CustomParameters {
     }
   }
 
+  static class NativeParameters {
+    @NonNull final OnNativeAdLoadedListener listener;
+    @NonNull final NativeAdFactory factory;
+    @Nullable final NativeAdOptions nativeAdOptions;
+    @Nullable final Map<String, Object> viewOptions;
+
+    NativeParameters(
+        @NonNull OnNativeAdLoadedListener listener,
+        @NonNull NativeAdFactory factory,
+        @Nullable NativeAdOptions nativeAdOptions,
+        @Nullable Map<String, Object> viewOptions) {
+      this.listener = listener;
+      this.factory = factory;
+      this.nativeAdOptions = nativeAdOptions;
+      this.viewOptions = viewOptions;
+    }
+  }
+
   protected FlutterAdLoaderAd(
       int adId,
       @NonNull AdInstanceManager manager,
@@ -204,7 +248,12 @@ void load() {
     // As of 20.0.0 of GMA, mockito is unable to mock AdLoader.
     if (request != null) {
       adLoader.loadAdLoaderAd(
-          adUnitId, adListener, request.asAdRequest(adUnitId), bannerParameters, customParameters);
+          adUnitId,
+          adListener,
+          request.asAdRequest(adUnitId),
+          bannerParameters,
+          customParameters,
+          nativeParameters);
       return;
     }
 
@@ -214,7 +263,8 @@ void load() {
           adListener,
           adManagerRequest.asAdManagerAdRequest(adUnitId),
           bannerParameters,
-          customParameters);
+          customParameters,
+          nativeParameters);
       return;
     }
 
@@ -245,6 +295,13 @@ public void onCustomFormatAdLoaded(@NonNull NativeCustomFormatAd ad) {
     manager.onAdLoaded(adId, null);
   }
 
+  @Override
+  public void onNativeAdLoaded(@NonNull NativeAd ad) {
+    view = nativeParameters.factory.createNativeAd(ad, nativeParameters.viewOptions);
+    ad.setOnPaidEventListener(new FlutterPaidEventListener(manager, this));
+    manager.onAdLoaded(adId, ad.getResponseInfo());
+  }
+
   @Override
   void dispose() {
     if (view == null) {

packages/google_mobile_ads/android/src/main/java/io/flutter/plugins/googlemobileads/FlutterCustomParameters.java

@@ -20,10 +20,10 @@ class FlutterCustomParameters {
 
   FlutterAdLoaderAd.CustomParameters asCustomParameters(
       @NonNull OnCustomFormatAdLoadedListener listener,
-      @NonNull Map<String, CustomAdFactory> availableFactories) {
+      @NonNull Map<String, CustomAdFactory> registeredFactories) {
     Map<String, CustomAdFactory> factories = new HashMap<>();
     for (String formatId : formatIds) {
-      factories.put(formatId, availableFactories.get(formatId));
+      factories.put(formatId, registeredFactories.get(formatId));
     }
     return new FlutterAdLoaderAd.CustomParameters(listener, factories, viewOptions);
   }

packages/google_mobile_ads/android/src/main/java/io/flutter/plugins/googlemobileads/FlutterNativeParameters.java

@@ -0,0 +1,48 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package io.flutter.plugins.googlemobileads;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import com.google.android.gms.ads.nativead.NativeAd.OnNativeAdLoadedListener;
+import com.google.android.gms.ads.nativead.NativeAdOptions;
+import io.flutter.plugins.googlemobileads.GoogleMobileAdsPlugin.NativeAdFactory;
+import java.util.Map;
+
+class FlutterNativeParameters {
+  @NonNull final String factoryId;
+  @Nullable final FlutterNativeAdOptions nativeAdOptions;
+  @Nullable final Map<String, Object> viewOptions;
+
+  FlutterNativeParameters(
+      @NonNull String factoryId,
+      @Nullable FlutterNativeAdOptions nativeAdOptions,
+      @Nullable Map<String, Object> viewOptions) {
+    this.factoryId = factoryId;
+    this.nativeAdOptions = nativeAdOptions;
+    this.viewOptions = viewOptions;
+  }
+
+  FlutterAdLoaderAd.NativeParameters asNativeParameters(
+      @NonNull OnNativeAdLoadedListener listener,
+      @NonNull Map<String, NativeAdFactory> registeredFactories) {
+    NativeAdOptions nativeAdOptions = null;
+    if (this.nativeAdOptions != null) {
+      nativeAdOptions = this.nativeAdOptions.asNativeAdOptions();
+    }
+    return new FlutterAdLoaderAd.NativeParameters(
+        listener, registeredFactories.get(factoryId), nativeAdOptions, viewOptions);
+  }
+}

packages/google_mobile_ads/android/src/main/java/io/flutter/plugins/googlemobileads/GoogleMobileAdsPlugin.java

@@ -488,6 +488,17 @@ public void onAdInspectorClosed(@Nullable AdInspectorError adInspectorError) {
           }
         }
 
+        final FlutterNativeParameters nativeParameters =
+            call.<FlutterNativeParameters>argument("native");
+        if (nativeParameters != null) {
+          if (nativeAdFactories.get(nativeParameters.factoryId) == null) {
+            final String message =
+                String.format("Can't find NativeAdFactory with id: %s", nativeParameters.factoryId);
+            result.error("AdLoaderAdError", message, null);
+            return;
+          }
+        }
+
         final FlutterAdLoaderAd adLoaderAd =
             new FlutterAdLoaderAd.Builder()
                 .setManager(instanceManager)
@@ -499,6 +510,8 @@ public void onAdInspectorClosed(@Nullable AdInspectorError adInspectorError) {
                 .setBanner(call.<FlutterBannerParameters>argument("banner"))
                 .setCustom(customParameters)
                 .withAvailableCustomFactories(customAdFactories)
+                .setNative(nativeParameters)
+                .withAvailableNativeFactories(nativeAdFactories)
                 .build();
         instanceManager.trackAd(adLoaderAd, call.<Integer>argument("adId"));
         adLoaderAd.load();

packages/google_mobile_ads/android/src/test/java/io/flutter/plugins/googlemobileads/AdMessageCodecTest.java

@@ -576,4 +576,27 @@ public void encodeCustomParameters() {
     assertEquals(result.viewOptions.size(), 1);
     assertEquals(result.viewOptions.get("key"), "value");
   }
+
+  @Test
+  public void encodeNativeParameters() {
+    final ByteBuffer data =
+        codec.encodeMessage(
+            new FlutterNativeParameters(
+                "factory-id",
+                new FlutterNativeAdOptions(1, 1, null, true, true, true),
+                Collections.singletonMap("key", "value")));
+
+    final FlutterNativeParameters result =
+        (FlutterNativeParameters) codec.decodeMessage((ByteBuffer) data.position(0));
+
+    assertEquals(result.factoryId, "factory-id");
+    assertEquals(result.nativeAdOptions.adChoicesPlacement, Integer.valueOf(1));
+    assertEquals(result.nativeAdOptions.mediaAspectRatio, Integer.valueOf(1));
+    assertNull(result.nativeAdOptions.videoOptions);
+    assertTrue(result.nativeAdOptions.requestCustomMuteThisAd);
+    assertTrue(result.nativeAdOptions.shouldRequestMultipleImages);
+    assertTrue(result.nativeAdOptions.shouldReturnUrlsForImageAssets);
+    assertEquals(result.viewOptions.size(), 1);
+    assertEquals(result.viewOptions.get("key"), "value");
+  }
 }