Keep strong references to Picasso notification icon loading targets

Before the Target would sometimes be garbage collected before being called with the loaded channel icon, since Picasso holds weak references to targets. This meant that sometimes a new streams notification  would not be shown, because the lambda that should have shown it had already been garbage collected.

app/src/main/java/org/schabi/newpipe/local/feed/notifications/NotificationHelper.kt

@@ -4,6 +4,8 @@ import android.app.NotificationManager
 import android.app.PendingIntent
 import android.content.Context
 import android.content.Intent
+import android.graphics.Bitmap
+import android.graphics.drawable.Drawable
 import android.net.Uri
 import android.os.Build
 import android.provider.Settings
@@ -11,6 +13,8 @@ import androidx.core.app.NotificationCompat
 import androidx.core.app.NotificationManagerCompat
 import androidx.core.content.ContextCompat
 import androidx.preference.PreferenceManager
+import com.squareup.picasso.Picasso
+import com.squareup.picasso.Target
 import org.schabi.newpipe.R
 import org.schabi.newpipe.extractor.stream.StreamInfoItem
 import org.schabi.newpipe.local.feed.service.FeedUpdateInfo
@@ -27,6 +31,8 @@ class NotificationHelper(val context: Context) {
         Context.NOTIFICATION_SERVICE
     ) as NotificationManager
 
+    private val iconLoadingTargets = ArrayList<Target>()
+
     /**
      * Show a notification about new streams from a single channel.
      * Opening the notification will open the corresponding channel page.
@@ -77,10 +83,29 @@ class NotificationHelper(val context: Context) {
             )
         )
 
-        PicassoHelper.loadNotificationIcon(data.avatarUrl) { bitmap ->
-            bitmap?.let { builder.setLargeIcon(it) } // set only if != null
-            manager.notify(data.pseudoId, builder.build())
+        // a Target is like a listener for image loading events
+        val target = object : Target {
+            override fun onBitmapLoaded(bitmap: Bitmap, from: Picasso.LoadedFrom) {
+                builder.setLargeIcon(bitmap) // set only if there is actually one
+                manager.notify(data.pseudoId, builder.build())
+                iconLoadingTargets.remove(this) // allow it to be garbage-collected
+            }
+
+            override fun onBitmapFailed(e: Exception, errorDrawable: Drawable) {
+                manager.notify(data.pseudoId, builder.build())
+                iconLoadingTargets.remove(this) // allow it to be garbage-collected
+            }
+
+            override fun onPrepareLoad(placeHolderDrawable: Drawable) {
+                // Nothing to do
+            }
         }
+
+        // add the target to the list to hold a strong reference and prevent it from being garbage
+        // collected, since Picasso only holds weak references to targets
+        iconLoadingTargets.add(target)
+
+        PicassoHelper.loadNotificationIcon(data.avatarUrl).into(target)
     }
 
     companion object {

app/src/main/java/org/schabi/newpipe/util/PicassoHelper.java

@@ -5,7 +5,6 @@ import static org.schabi.newpipe.extractor.utils.Utils.isBlank;
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.graphics.Bitmap;
-import android.graphics.drawable.Drawable;
 
 import androidx.annotation.Nullable;
 
@@ -14,7 +13,6 @@ import com.squareup.picasso.LruCache;
 import com.squareup.picasso.OkHttp3Downloader;
 import com.squareup.picasso.Picasso;
 import com.squareup.picasso.RequestCreator;
-import com.squareup.picasso.Target;
 import com.squareup.picasso.Transformation;
 
 import org.schabi.newpipe.R;
@@ -22,7 +20,6 @@ import org.schabi.newpipe.R;
 import java.io.File;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
-import java.util.function.Consumer;
 
 import okhttp3.OkHttpClient;
 
@@ -120,6 +117,10 @@ public final class PicassoHelper {
         return picassoInstance.load(url);
     }
 
+    public static RequestCreator loadNotificationIcon(final String url) {
+        return loadImageDefault(url, R.drawable.ic_newpipe_triangle_white);
+    }
+
 
     public static RequestCreator loadScaledDownThumbnail(final Context context, final String url) {
         // scale down the notification thumbnail for performance
@@ -170,27 +171,6 @@ public final class PicassoHelper {
         return picassoCache.get(imageUrl + "\n");
     }
 
-    public static void loadNotificationIcon(final String url,
-                                            final Consumer<Bitmap> bitmapConsumer) {
-        loadImageDefault(url, R.drawable.ic_newpipe_triangle_white)
-                .into(new Target() {
-                    @Override
-                    public void onBitmapLoaded(final Bitmap bitmap, final Picasso.LoadedFrom from) {
-                        bitmapConsumer.accept(bitmap);
-                    }
-
-                    @Override
-                    public void onBitmapFailed(final Exception e, final Drawable errorDrawable) {
-                        bitmapConsumer.accept(null);
-                    }
-
-                    @Override
-                    public void onPrepareLoad(final Drawable placeHolderDrawable) {
-                        // Nothing to do
-                    }
-                });
-    }
-
 
     private static RequestCreator loadImageDefault(final String url, final int placeholderResId) {
         return loadImageDefault(url, placeholderResId, true);