[firebase_admob] Fixes memory leak by removing static reference for Activities

packages/firebase_admob/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.0+6
+
+* Fix Android memory leak.
+
 ## 0.9.0+5
 
 * Update documentation to reflect new repository location.

packages/firebase_admob/android/src/main/java/io/flutter/plugins/firebaseadmob/FirebaseAdMobPlugin.java

@@ -20,6 +20,7 @@ public class FirebaseAdMobPlugin implements MethodCallHandler {
 
   private final Registrar registrar;
   private final MethodChannel channel;
+  private final MobileAdRegistrar adRegistrar;
 
   RewardedVideoAdWrapper rewardedWrapper;
 
@@ -31,12 +32,17 @@ public static void registerWith(Registrar registrar) {
     }
     final MethodChannel channel =
         new MethodChannel(registrar.messenger(), "plugins.flutter.io/firebase_admob");
-    channel.setMethodCallHandler(new FirebaseAdMobPlugin(registrar, channel));
+
+    final MobileAdRegistrar adRegistry = new MobileAdRegistrar();
+
+    channel.setMethodCallHandler(new FirebaseAdMobPlugin(registrar, channel, adRegistry));
   }
 
-  private FirebaseAdMobPlugin(Registrar registrar, MethodChannel channel) {
+  private FirebaseAdMobPlugin(
+      Registrar registrar, MethodChannel channel, MobileAdRegistrar adRegistrar) {
     this.registrar = registrar;
     this.channel = channel;
+    this.adRegistrar = adRegistrar;
     FirebaseApp.initializeApp(registrar.context());
     rewardedWrapper = new RewardedVideoAdWrapper(registrar.activity(), channel);
   }
@@ -84,7 +90,7 @@ private void callLoadBannerAd(
       adSize = new AdSize(width, height);
     }
 
-    MobileAd.Banner banner = MobileAd.createBanner(id, adSize, activity, channel);
+    MobileAd.Banner banner = adRegistrar.createBanner(id, adSize, activity, channel);
 
     if (banner.status != MobileAd.Status.CREATED) {
       if (banner.status == MobileAd.Status.FAILED)
@@ -143,7 +149,7 @@ private void callLoadRewardedVideoAd(MethodCall call, Result result) {
   }
 
   private void callShowAd(int id, MethodCall call, Result result) {
-    MobileAd ad = MobileAd.getAdForId(id);
+    MobileAd ad = adRegistrar.getAdForId(id);
     if (ad == null) {
       result.error("ad_not_loaded", "show failed, the specified ad was not loaded id=" + id, null);
       return;
@@ -164,7 +170,8 @@ private void callShowAd(int id, MethodCall call, Result result) {
   }
 
   private void callIsAdLoaded(int id, MethodCall call, Result result) {
-    MobileAd ad = MobileAd.getAdForId(id);
+    MobileAd ad = adRegistrar.getAdForId(id);
+
     if (ad == null) {
       result.error("no_ad_for_id", "isAdLoaded failed, no add exists for id=" + id, null);
       return;
@@ -182,7 +189,8 @@ private void callShowRewardedVideoAd(MethodCall call, Result result) {
   }
 
   private void callDisposeAd(int id, MethodCall call, Result result) {
-    MobileAd ad = MobileAd.getAdForId(id);
+    MobileAd ad = adRegistrar.getAdForId(id);
+
     if (ad == null) {
       result.error("no_ad_for_id", "dispose failed, no add exists for id=" + id, null);
       return;
@@ -212,7 +220,7 @@ public void onMethodCall(MethodCall call, Result result) {
         callLoadBannerAd(id, activity, channel, call, result);
         break;
       case "loadInterstitialAd":
-        callLoadInterstitialAd(MobileAd.createInterstitial(id, activity, channel), call, result);
+        callLoadInterstitialAd(adRegistrar.createInterstitial(id, activity, channel), call, result);
         break;
       case "loadRewardedVideoAd":
         callLoadRewardedVideoAd(call, result);

packages/firebase_admob/android/src/main/java/io/flutter/plugins/firebaseadmob/MobileAd.java

@@ -6,7 +6,6 @@
 
 import android.app.Activity;
 import android.util.Log;
-import android.util.SparseArray;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewGroup;
@@ -21,15 +20,15 @@
 
 abstract class MobileAd extends AdListener {
   private static final String TAG = "flutter";
-  private static SparseArray<MobileAd> allAds = new SparseArray<MobileAd>();
 
+  private final MethodChannel channel;
+  private final MobileAdRegistrar adRegistrar;
   final Activity activity;
-  final MethodChannel channel;
   final int id;
-  Status status;
   double anchorOffset;
   double horizontalCenterOffset;
   int anchorType;
+  Status status;
 
   enum Status {
     CREATED,
@@ -39,29 +38,17 @@ enum Status {
     LOADED,
   }
 
-  private MobileAd(int id, Activity activity, MethodChannel channel) {
+  private MobileAd(
+      MobileAdRegistrar adRegistrar, int id, Activity activity, MethodChannel channel) {
     this.id = id;
     this.activity = activity;
     this.channel = channel;
     this.status = Status.CREATED;
     this.anchorOffset = 0.0;
     this.horizontalCenterOffset = 0.0;
     this.anchorType = Gravity.BOTTOM;
-    allAds.put(id, this);
-  }
-
-  static Banner createBanner(Integer id, AdSize adSize, Activity activity, MethodChannel channel) {
-    MobileAd ad = getAdForId(id);
-    return (ad != null) ? (Banner) ad : new Banner(id, adSize, activity, channel);
-  }
-
-  static Interstitial createInterstitial(Integer id, Activity activity, MethodChannel channel) {
-    MobileAd ad = getAdForId(id);
-    return (ad != null) ? (Interstitial) ad : new Interstitial(id, activity, channel);
-  }
-
-  static MobileAd getAdForId(Integer id) {
-    return allAds.get(id);
+    this.adRegistrar = adRegistrar;
+    adRegistrar.register(id, this);
   }
 
   Status getStatus() {
@@ -73,7 +60,7 @@ Status getStatus() {
   abstract void show();
 
   void dispose() {
-    allAds.remove(id);
+    adRegistrar.unregister(id);
   }
 
   private Map<String, Object> argumentsMap(Object... args) {
@@ -127,8 +114,13 @@ static class Banner extends MobileAd {
     private AdView adView;
     private AdSize adSize;
 
-    private Banner(Integer id, AdSize adSize, Activity activity, MethodChannel channel) {
-      super(id, activity, channel);
+    Banner(
+        MobileAdRegistrar adRegistrar,
+        Integer id,
+        AdSize adSize,
+        Activity activity,
+        MethodChannel channel) {
+      super(adRegistrar, id, activity, channel);
       this.adSize = adSize;
     }
 
@@ -195,8 +187,8 @@ void dispose() {
   static class Interstitial extends MobileAd {
     private InterstitialAd interstitial = null;
 
-    private Interstitial(int id, Activity activity, MethodChannel channel) {
-      super(id, activity, channel);
+    Interstitial(MobileAdRegistrar adRegistrar, int id, Activity activity, MethodChannel channel) {
+      super(adRegistrar, id, activity, channel);
     }
 
     @Override

packages/firebase_admob/android/src/main/java/io/flutter/plugins/firebaseadmob/MobileAdRegistrar.java

@@ -0,0 +1,48 @@
+package io.flutter.plugins.firebaseadmob;
+
+import android.app.Activity;
+import android.util.SparseArray;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import com.google.android.gms.ads.AdSize;
+import io.flutter.plugin.common.MethodChannel;
+
+/* Class that acts as Factory and registry for MobileAds. */
+class MobileAdRegistrar {
+  private SparseArray<MobileAd> allAds = new SparseArray<>();
+
+  /* Returns a MobileAd if it is registered in this Registrar. */
+  @Nullable
+  MobileAd getAdForId(Integer id) {
+    return allAds.get(id);
+  }
+
+  /* Registers a new MobileAd with the given id. */
+  void register(int id, MobileAd ad) {
+    allAds.put(id, ad);
+  }
+
+  /* Returns an already registered Banner with the given id or creates a new Banner. */
+  @NonNull
+  MobileAd.Banner createBanner(
+      Integer id, AdSize adSize, Activity activity, MethodChannel channel) {
+    MobileAd ad = getAdForId(id);
+    return (ad != null)
+        ? (MobileAd.Banner) ad
+        : new MobileAd.Banner(this, id, adSize, activity, channel);
+  }
+
+  /* Returns an already registered Interstitial with the given id or creates a new Interstitial. */
+  @NonNull
+  MobileAd.Interstitial createInterstitial(Integer id, Activity activity, MethodChannel channel) {
+    MobileAd ad = getAdForId(id);
+    return (ad != null)
+        ? (MobileAd.Interstitial) ad
+        : new MobileAd.Interstitial(this, id, activity, channel);
+  }
+
+  /* Unregisters a MobileAd with the given id. */
+  void unregister(Integer id) {
+    allAds.remove(id);
+  }
+}

packages/firebase_admob/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for Firebase AdMob, supporting
   banner, interstitial (full-screen), and rewarded video ads
 author: Flutter Team <[email protected]>
 homepage: https://github.com/FirebaseExtended/flutterfire/tree/master/packages/firebase_admob
-version: 0.9.0+5
+version: 0.9.0+6
 
 flutter:
   plugin: