DownloadService: Minor improvements

* Avoid ActivityManager log spam by only calling startForeground once,
  and subsequently updating the notification via NotificationManager.
* Tweak demo app service to make it a tiny bit easier to swap the Scheduler.

PiperOrigin-RevId: 397179398

demos/main/src/main/java/com/google/android/exoplayer2/demo/DemoDownloadService.java

@@ -26,6 +26,7 @@ import com.google.android.exoplayer2.offline.DownloadManager;
 import com.google.android.exoplayer2.offline.DownloadService;
 import com.google.android.exoplayer2.offline.DownloadService;
 import com.google.android.exoplayer2.scheduler.PlatformScheduler;
 import com.google.android.exoplayer2.scheduler.PlatformScheduler;
 import com.google.android.exoplayer2.scheduler.Requirements;
 import com.google.android.exoplayer2.scheduler.Requirements;
+import com.google.android.exoplayer2.scheduler.Scheduler;
 import com.google.android.exoplayer2.ui.DownloadNotificationHelper;
 import com.google.android.exoplayer2.ui.DownloadNotificationHelper;
 import com.google.android.exoplayer2.util.NotificationUtil;
 import com.google.android.exoplayer2.util.NotificationUtil;
 import com.google.android.exoplayer2.util.Util;
 import com.google.android.exoplayer2.util.Util;
@@ -61,7 +62,7 @@ public class DemoDownloadService extends DownloadService {
   }
   }
 
 
   @Override
   @Override
-  protected PlatformScheduler getScheduler() {
+  protected Scheduler getScheduler() {
     return Util.SDK_INT >= 21 ? new PlatformScheduler(this, JOB_ID) : null;
     return Util.SDK_INT >= 21 ? new PlatformScheduler(this, JOB_ID) : null;
   }
   }
 
 

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadService.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.offline;
 import static com.google.android.exoplayer2.offline.Download.STOP_REASON_NONE;
 import static com.google.android.exoplayer2.offline.Download.STOP_REASON_NONE;
 
 
 import android.app.Notification;
 import android.app.Notification;
+import android.app.NotificationManager;
 import android.app.Service;
 import android.app.Service;
 import android.content.Context;
 import android.content.Context;
 import android.content.Intent;
 import android.content.Intent;
@@ -889,8 +890,16 @@ public abstract class DownloadService extends Service {
       List<Download> downloads = Assertions.checkNotNull(downloadManager).getCurrentDownloads();
       List<Download> downloads = Assertions.checkNotNull(downloadManager).getCurrentDownloads();
       @Requirements.RequirementFlags
       @Requirements.RequirementFlags
       int notMetRequirements = downloadManager.getNotMetRequirements();
       int notMetRequirements = downloadManager.getNotMetRequirements();
-      startForeground(notificationId, getForegroundNotification(downloads, notMetRequirements));
+      Notification notification = getForegroundNotification(downloads, notMetRequirements);
+      if (!notificationDisplayed) {
+        startForeground(notificationId, notification);
         notificationDisplayed = true;
         notificationDisplayed = true;
+      } else {
+        // Update the notification via NotificationManager rather than by repeatedly calling
+        // startForeground, since the latter can cause ActivityManager log spam.
+        ((NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE))
+            .notify(notificationId, notification);
+      }
       if (periodicUpdatesStarted) {
       if (periodicUpdatesStarted) {
         handler.removeCallbacksAndMessages(null);
         handler.removeCallbacksAndMessages(null);
         handler.postDelayed(this::update, updateInterval);
         handler.postDelayed(this::update, updateInterval);