Fix download percentage reporting

- When calculating the downloaded percentage in DASH, there was no
  way to disambiguate between 0 of 0 segments being downloaded because
  there are no cached indexes (i.e. 0% downloaded) and 0 of 0 segments
  being downloaded because the index defines 0 segments (i.e. 100%
  downloaded).
- Also replace use of NaN with a named constant.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=194453202

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

@@ -204,7 +204,8 @@ public class DownloadActivity extends Activity {
     public RepresentationItem(Parcelable key, String title, float percentDownloaded) {
       this.key = key;
       this.title = title;
-      this.percentDownloaded = (int) percentDownloaded;
+      this.percentDownloaded =
+          (int) (percentDownloaded == C.PERCENTAGE_UNSET ? 0 : percentDownloaded);
     }
 
     @Override

library/core/src/main/java/com/google/android/exoplayer2/C.java

@@ -64,6 +64,9 @@ public final class C {
    */
   public static final int LENGTH_UNSET = -1;
 
+  /** Represents an unset or unknown percentage. */
+  public static final int PERCENTAGE_UNSET = -1;
+
   /**
    * The number of microseconds in one second.
    */

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

@@ -541,14 +541,11 @@ public final class DownloadManager {
     /** The state of the task. See {@link State}. */
     public final @State int state;
     /**
-     * The download percentage, or {@link Float#NaN} if it can't be calculated or the task is for
+     * The estimated download percentage, or {@link C#PERCENTAGE_UNSET} if no estimate is available
-     * removing.
+     * or if this is a removal task.
      */
     public final float downloadPercentage;
-    /**
+    /** The total number of downloaded bytes. */
-     * The downloaded bytes, or {@link C#LENGTH_UNSET} if it hasn't been calculated yet or the task
-     * is for removing.
-     */
     public final long downloadedBytes;
     /** If {@link #state} is {@link #STATE_ERROR} then this is the cause, otherwise null. */
     public final Throwable error;
@@ -648,19 +645,16 @@ public final class DownloadManager {
     }
 
     /**
-     * Returns the download percentage, or {@link Float#NaN} if it can't be calculated yet. This
+     * Returns the estimated download percentage, or {@link C#PERCENTAGE_UNSET} if no estimate is
-     * value can be an estimation.
+     * available.
      */
     public float getDownloadPercentage() {
-      return downloader != null ? downloader.getDownloadPercentage() : Float.NaN;
+      return downloader != null ? downloader.getDownloadPercentage() : C.PERCENTAGE_UNSET;
     }
 
-    /**
+    /** Returns the total number of downloaded bytes. */
-     * Returns the total number of downloaded bytes, or {@link C#LENGTH_UNSET} if it hasn't been
-     * calculated yet.
-     */
     public long getDownloadedBytes() {
-      return downloader != null ? downloader.getDownloadedBytes() : C.LENGTH_UNSET;
+      return downloader != null ? downloader.getDownloadedBytes() : 0;
     }
 
     @Override

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

@@ -29,8 +29,6 @@ public interface Downloader {
    * @throws DownloadException Thrown if the media cannot be downloaded.
    * @throws InterruptedException If the thread has been interrupted.
    * @throws IOException Thrown when there is an io error while reading from cache.
-   * @see #getDownloadedBytes()
-   * @see #getDownloadPercentage()
    */
   void init() throws InterruptedException, IOException;
 
@@ -50,20 +48,12 @@ public interface Downloader {
    */
   void remove() throws InterruptedException;
 
-  /**
+  /** Returns the total number of downloaded bytes. */
-   * Returns the total number of downloaded bytes, or {@link C#LENGTH_UNSET} if it hasn't been
-   * calculated yet.
-   *
-   * @see #init()
-   */
   long getDownloadedBytes();
 
   /**
-   * Returns the download percentage, or {@link Float#NaN} if it can't be calculated yet. This
+   * Returns the estimated download percentage, or {@link C#PERCENTAGE_UNSET} if no estimate is
-   * value can be an estimation.
+   * available.
-   *
-   * @see #init()
    */
   float getDownloadPercentage();
-
 }

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

@@ -83,7 +83,8 @@ public final class ProgressiveDownloader implements Downloader {
   @Override
   public float getDownloadPercentage() {
     long contentLength = cachingCounters.contentLength;
-    return contentLength == C.LENGTH_UNSET ? Float.NaN
+    return contentLength == C.LENGTH_UNSET
+        ? C.PERCENTAGE_UNSET
         : ((cachingCounters.totalCachedBytes() * 100f) / contentLength);
   }
 

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

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.offline;
 
 import android.net.Uri;
 import android.support.annotation.NonNull;
+import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
@@ -33,9 +34,6 @@ import java.util.List;
 /**
  * Base class for multi segment stream downloaders.
  *
- * <p>All of the methods are blocking. Also they are not thread safe, except {@link
- * #getTotalSegments()}, {@link #getDownloadedSegments()} and {@link #getDownloadedBytes()}.
- *
  * @param <M> The type of the manifest object.
  * @param <K> The type of the representation key object.
  */
@@ -101,6 +99,9 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
     return getManifestIfNeeded(false);
   }
 
+  /** Returns keys for all representations. */
+  public abstract K[] getAllRepresentationKeys() throws IOException;
+
   /**
    * Selects multiple representations pointed to by the keys for downloading, checking status. Any
    * previous selection is cleared. If keys array is null or empty then all representations are
@@ -113,25 +114,13 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
   }
 
   /**
-   * Returns keys for all representations.
+   * Initializes the downloader for the selected representations.
    *
-   * @see #selectRepresentations(Object[])
+   * @throws IOException Thrown when there is an error downloading.
-   */
-  public abstract K[] getAllRepresentationKeys() throws IOException;
-
-  /**
-   * Initializes the total segments, downloaded segments and downloaded bytes counters for the
-   * selected representations.
-   *
-   * @throws IOException Thrown when there is an io error while reading from cache.
-   * @throws DownloadException Thrown if the media cannot be downloaded.
    * @throws InterruptedException If the thread has been interrupted.
-   * @see #getTotalSegments()
-   * @see #getDownloadedSegments()
-   * @see #getDownloadedBytes()
    */
   @Override
-  public final void init() throws InterruptedException, IOException {
+  public final void init() throws IOException, InterruptedException {
     try {
       getManifestIfNeeded(true);
     } catch (IOException e) {
@@ -140,7 +129,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
     }
     try {
       initStatus(true);
-    } catch (IOException | InterruptedException e) {
+    } catch (IOException e) {
       resetCounters();
       throw e;
     }
@@ -150,8 +139,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
    * Downloads the content for the selected representations in sync or resumes a previously stopped
    * download.
    *
-   * @throws IOException Thrown when there is an io error while downloading.
+   * @throws IOException Thrown when there is an error downloading.
-   * @throws DownloadException Thrown if the media cannot be downloaded.
    * @throws InterruptedException If the thread has been interrupted.
    */
   @Override
@@ -174,32 +162,6 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
     }
   }
 
-  /**
-   * Returns the total number of segments in the representations which are selected, or {@link
-   * C#LENGTH_UNSET} if it hasn't been calculated yet.
-   *
-   * @see #init()
-   */
-  public final int getTotalSegments() {
-    return totalSegments;
-  }
-
-  /**
-   * Returns the total number of downloaded segments in the representations which are selected, or
-   * {@link C#LENGTH_UNSET} if it hasn't been calculated yet.
-   *
-   * @see #init()
-   */
-  public final int getDownloadedSegments() {
-    return downloadedSegments;
-  }
-
-  /**
-   * Returns the total number of downloaded bytes in the representations which are selected, or
-   * {@link C#LENGTH_UNSET} if it hasn't been calculated yet.
-   *
-   * @see #init()
-   */
   @Override
   public final long getDownloadedBytes() {
     return downloadedBytes;
@@ -211,7 +173,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
     int totalSegments = this.totalSegments;
     int downloadedSegments = this.downloadedSegments;
     if (totalSegments == C.LENGTH_UNSET || downloadedSegments == C.LENGTH_UNSET) {
-      return Float.NaN;
+      return C.PERCENTAGE_UNSET;
     }
     return totalSegments == 0 ? 100f : (downloadedSegments * 100f) / totalSegments;
   }
@@ -228,7 +190,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
     if (manifest != null) {
       List<Segment> segments = null;
       try {
-        segments = getSegments(offlineDataSource, manifest, true);
+        segments = getSegments(offlineDataSource, manifest, true).first;
       } catch (IOException e) {
         // Ignore exceptions. We do our best with what's available offline.
       }
@@ -263,16 +225,17 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
    * @throws InterruptedException Thrown if the thread was interrupted.
    * @throws IOException Thrown if {@code allowPartialIndex} is false and a load error occurs, or if
    *     the media is not in a form that allows for its segments to be listed.
-   * @return A list of {@link Segment}s for given keys.
+   * @return A list of {@link Segment}s for given keys, and a boolean indicating whether the list is
+   *     complete.
    */
-  protected abstract List<Segment> getSegments(
+  protected abstract Pair<List<Segment>, Boolean> getSegments(
       DataSource dataSource, M manifest, boolean allowIncompleteIndex)
       throws InterruptedException, IOException;
 
   private void resetCounters() {
     totalSegments = C.LENGTH_UNSET;
-    downloadedSegments = C.LENGTH_UNSET;
+    downloadedSegments = 0;
-    downloadedBytes = C.LENGTH_UNSET;
+    downloadedBytes = 0;
   }
 
   private void remove(Uri uri) {
@@ -289,9 +252,11 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M, K>, K>
       throws IOException, InterruptedException {
     DataSource dataSource = getDataSource(offline);
     M filteredManifest = keys.isEmpty() ? manifest : manifest.copy(keys);
-    List<Segment> segments = getSegments(dataSource, filteredManifest, offline);
+    Pair<List<Segment>, Boolean> result = getSegments(dataSource, filteredManifest, offline);
+    List<Segment> segments = result.first;
+    boolean isSegmentListComplete = result.second;
     CachingCounters cachingCounters = new CachingCounters();
-    totalSegments = segments.size();
+    totalSegments = isSegmentListComplete ? segments.size() : C.LENGTH_UNSET;
     downloadedSegments = 0;
     downloadedBytes = 0;
     for (int i = segments.size() - 1; i >= 0; i--) {

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/offline/DashDownloader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.source.dash.offline;
 
 import android.net.Uri;
+import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.extractor.ChunkIndex;
 import com.google.android.exoplayer2.offline.DownloadException;
@@ -39,9 +40,6 @@ import java.util.List;
 /**
  * Helper class to download DASH streams.
  *
- * <p>Except {@link #getTotalSegments()}, {@link #getDownloadedSegments()} and {@link
- * #getDownloadedBytes()}, this class isn't thread safe.
- *
  * <p>Example usage:
  *
  * <pre>{@code
@@ -89,29 +87,32 @@ public final class DashDownloader extends SegmentDownloader<DashManifest, Repres
   }
 
   @Override
-  protected List<Segment> getSegments(
+  protected Pair<List<Segment>, Boolean> getSegments(
       DataSource dataSource, DashManifest manifest, boolean allowIndexLoadErrors)
       throws InterruptedException, IOException {
     ArrayList<Segment> segments = new ArrayList<>();
+    boolean segmentListComplete = true;
     for (int i = 0; i < manifest.getPeriodCount(); i++) {
       Period period = manifest.getPeriod(i);
       long periodStartUs = C.msToUs(period.startMs);
       long periodDurationUs = manifest.getPeriodDurationUs(i);
       List<AdaptationSet> adaptationSets = period.adaptationSets;
       for (int j = 0; j < adaptationSets.size(); j++) {
-        addSegmentsForAdaptationSet(
+        if (!addSegmentsForAdaptationSet(
             dataSource,
             adaptationSets.get(j),
             periodStartUs,
             periodDurationUs,
             allowIndexLoadErrors,
-            segments);
+            segments)) {
+          segmentListComplete = false;
         }
       }
-    return segments;
+    }
+    return Pair.<List<Segment>, Boolean>create(segments, segmentListComplete);
   }
 
-  private static void addSegmentsForAdaptationSet(
+  private static boolean addSegmentsForAdaptationSet(
       DataSource dataSource,
       AdaptationSet adaptationSet,
       long periodStartUs,
@@ -119,6 +120,7 @@ public final class DashDownloader extends SegmentDownloader<DashManifest, Repres
       boolean allowIndexLoadErrors,
       ArrayList<Segment> out)
       throws IOException, InterruptedException {
+    boolean segmentListComplete = true;
     for (int i = 0; i < adaptationSet.representations.size(); i++) {
       Representation representation = adaptationSet.representations.get(i);
       DashSegmentIndex index;
@@ -129,12 +131,12 @@ public final class DashDownloader extends SegmentDownloader<DashManifest, Repres
           throw new DownloadException("Missing segment index");
         }
       } catch (IOException e) {
-        if (allowIndexLoadErrors) {
+        if (!allowIndexLoadErrors) {
-          // Loading failed, but load errors are allowed. Advance to the next representation.
-          continue;
-        } else {
           throw e;
         }
+        // Loading failed, but load errors are allowed. Advance to the next representation.
+        segmentListComplete = false;
+        continue;
       }
 
       int segmentCount = index.getSegmentCount(periodDurationUs);
@@ -157,6 +159,8 @@ public final class DashDownloader extends SegmentDownloader<DashManifest, Repres
         addSegment(periodStartUs + index.getTimeUs(j), baseUrl, index.getSegmentUrl(j), out);
       }
     }
+
+    return segmentListComplete;
   }
 
   private static void addSegment(

library/dash/src/test/java/com/google/android/exoplayer2/source/dash/offline/DashDownloaderTest.java

@@ -26,7 +26,6 @@ import static org.junit.Assert.fail;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
-import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.offline.DownloadException;
 import com.google.android.exoplayer2.offline.DownloaderConstructorHelper;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
@@ -65,7 +64,7 @@ public class DashDownloaderTest {
   }
 
   @After
-  public void tearDown() throws Exception {
+  public void tearDown() {
     Util.recursiveDelete(tempFolder);
   }
 
@@ -311,11 +310,11 @@ public class DashDownloaderTest {
             .setRandomData("audio_segment_3", 6);
     DashDownloader dashDownloader = getDashDownloader(fakeDataSet);
 
-    assertCounters(dashDownloader, C.LENGTH_UNSET, C.LENGTH_UNSET, C.LENGTH_UNSET);
+    assertThat(dashDownloader.getDownloadedBytes()).isEqualTo(0);
 
     dashDownloader.selectRepresentations(new RepresentationKey[] {new RepresentationKey(0, 0, 0)});
     dashDownloader.init();
-    assertCounters(dashDownloader, C.LENGTH_UNSET, C.LENGTH_UNSET, C.LENGTH_UNSET);
+    assertThat(dashDownloader.getDownloadedBytes()).isEqualTo(0);
 
     // downloadRepresentations fails after downloading init data, segment 1 and 2 bytes in segment 2
     try {
@@ -325,11 +324,10 @@ public class DashDownloaderTest {
       // ignore
     }
     dashDownloader.init();
-    assertCounters(dashDownloader, 4, 2, 10 + 4 + 2);
+    assertThat(dashDownloader.getDownloadedBytes()).isEqualTo(10 + 4 + 2);
 
     dashDownloader.download();
-
+    assertThat(dashDownloader.getDownloadedBytes()).isEqualTo(10 + 4 + 5 + 6);
-    assertCounters(dashDownloader, 4, 4, 10 + 4 + 5 + 6);
   }
 
   @Test
@@ -399,13 +397,4 @@ public class DashDownloaderTest {
     return new DashDownloader(TEST_MPD_URI, new DownloaderConstructorHelper(cache, factory));
   }
 
-  private static void assertCounters(
-      DashDownloader dashDownloader,
-      int totalSegments,
-      int downloadedSegments,
-      int downloadedBytes) {
-    assertThat(dashDownloader.getTotalSegments()).isEqualTo(totalSegments);
-    assertThat(dashDownloader.getDownloadedSegments()).isEqualTo(downloadedSegments);
-    assertThat(dashDownloader.getDownloadedBytes()).isEqualTo(downloadedBytes);
-  }
 }

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/offline/HlsDownloader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.source.hls.offline;
 
 import android.net.Uri;
+import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.offline.DownloaderConstructorHelper;
 import com.google.android.exoplayer2.offline.SegmentDownloader;
@@ -70,17 +71,17 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, Re
   }
 
   @Override
-  protected List<Segment> getSegments(
+  protected Pair<List<Segment>, Boolean> getSegments(
-      DataSource dataSource,
+      DataSource dataSource, HlsMasterPlaylist manifest, boolean allowIndexLoadErrors)
-      HlsMasterPlaylist manifest,
+      throws IOException {
-      boolean allowIndexLoadErrors)
-      throws InterruptedException, IOException {
     HashSet<Uri> encryptionKeyUris = new HashSet<>();
     ArrayList<HlsUrl> renditionUrls = new ArrayList<>();
     renditionUrls.addAll(manifest.variants);
     renditionUrls.addAll(manifest.audios);
     renditionUrls.addAll(manifest.subtitles);
     ArrayList<Segment> segments = new ArrayList<>();
+
+    boolean segmentListComplete = true;
     for (HlsUrl renditionUrl : renditionUrls) {
       HlsMediaPlaylist mediaPlaylist = null;
       Uri uri = UriUtil.resolveToUri(manifest.baseUri, renditionUrl.url);
@@ -90,6 +91,7 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, Re
         if (!allowIndexLoadErrors) {
           throw e;
         }
+        segmentListComplete = false;
       }
       segments.add(new Segment(mediaPlaylist != null ? mediaPlaylist.startTimeUs : Long.MIN_VALUE,
           new DataSpec(uri)));
@@ -109,7 +111,7 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, Re
         addSegment(segments, mediaPlaylist, segment, encryptionKeyUris);
       }
     }
-    return segments;
+    return Pair.<List<Segment>, Boolean>create(segments, segmentListComplete);
   }
 
   private static HlsPlaylist loadManifest(DataSource dataSource, Uri uri) throws IOException {

library/hls/src/test/java/com/google/android/exoplayer2/source/hls/offline/HlsDownloaderTest.java

@@ -111,8 +111,6 @@ public class HlsDownloaderTest {
     hlsDownloader.selectRepresentations(getKeys(MEDIA_PLAYLIST_1_URI));
     hlsDownloader.download();
 
-    assertThat(hlsDownloader.getTotalSegments()).isEqualTo(4);
-    assertThat(hlsDownloader.getDownloadedSegments()).isEqualTo(4);
     assertThat(hlsDownloader.getDownloadedBytes())
         .isEqualTo(MEDIA_PLAYLIST_DATA.length + 10 + 11 + 12);
   }
@@ -126,8 +124,6 @@ public class HlsDownloaderTest {
     newHlsDownloader.selectRepresentations(getKeys(MEDIA_PLAYLIST_1_URI));
     newHlsDownloader.init();
 
-    assertThat(newHlsDownloader.getTotalSegments()).isEqualTo(4);
-    assertThat(newHlsDownloader.getDownloadedSegments()).isEqualTo(4);
     assertThat(newHlsDownloader.getDownloadedBytes())
         .isEqualTo(MEDIA_PLAYLIST_DATA.length + 10 + 11 + 12);
   }

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/offline/SsDownloader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.source.smoothstreaming.offline;
 
 import android.net.Uri;
+import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.offline.DownloaderConstructorHelper;
 import com.google.android.exoplayer2.offline.SegmentDownloader;
@@ -34,9 +35,6 @@ import java.util.List;
 /**
  * Helper class to download SmoothStreaming streams.
  *
- * <p>Except {@link #getTotalSegments()}, {@link #getDownloadedSegments()} and {@link
- * #getDownloadedBytes()}, this class isn't thread safe.
- *
  * <p>Example usage:
  *
  * <pre>{@code
@@ -84,9 +82,8 @@ public final class SsDownloader extends SegmentDownloader<SsManifest, TrackKey>
   }
 
   @Override
-  protected List<Segment> getSegments(
+  protected Pair<List<Segment>, Boolean> getSegments(
-      DataSource dataSource, SsManifest manifest, boolean allowIndexLoadErrors)
+      DataSource dataSource, SsManifest manifest, boolean allowIndexLoadErrors) throws IOException {
-      throws InterruptedException, IOException {
     ArrayList<Segment> segments = new ArrayList<>();
     for (StreamElement streamElement : manifest.streamElements) {
       for (int i = 0; i < streamElement.formats.length; i++) {
@@ -98,7 +95,7 @@ public final class SsDownloader extends SegmentDownloader<SsManifest, TrackKey>
         }
       }
     }
-    return segments;
+    return Pair.<List<Segment>, Boolean>create(segments, true);
   }
 
 }

library/ui/src/main/java/com/google/android/exoplayer2/ui/DownloadNotificationUtil.java

@@ -19,6 +19,7 @@ import android.app.Notification;
 import android.content.Context;
 import android.support.annotation.Nullable;
 import android.support.v4.app.NotificationCompat;
+import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.offline.DownloadManager;
 import com.google.android.exoplayer2.offline.DownloadManager.DownloadState;
 import com.google.android.exoplayer2.util.ErrorMessageProvider;
@@ -48,31 +49,31 @@ public final class DownloadNotificationUtil {
       String channelId,
       @Nullable String message) {
     float totalPercentage = 0;
-    int determinatePercentageCount = 0;
+    int downloadTaskCount = 0;
-    boolean isAnyDownloadActive = false;
+    boolean allDownloadPercentagesUnknown = true;
+    boolean haveDownloadedBytes = false;
     for (DownloadState downloadState : downloadStates) {
       if (downloadState.downloadAction.isRemoveAction
           || downloadState.state != DownloadState.STATE_STARTED) {
         continue;
       }
-      float percentage = downloadState.downloadPercentage;
+      if (downloadState.downloadPercentage != C.PERCENTAGE_UNSET) {
-      if (!Float.isNaN(percentage)) {
+        allDownloadPercentagesUnknown = false;
-        totalPercentage += percentage;
+        totalPercentage += downloadState.downloadPercentage;
-        determinatePercentageCount++;
       }
-      isAnyDownloadActive = true;
+      haveDownloadedBytes |= downloadState.downloadedBytes > 0;
+      downloadTaskCount++;
     }
 
-    int titleStringId = isAnyDownloadActive ? R.string.exo_download_downloading : NULL_STRING_ID;
+    boolean haveDownloadTasks = downloadTaskCount > 0;
+    int titleStringId = haveDownloadTasks ? R.string.exo_download_downloading : NULL_STRING_ID;
     NotificationCompat.Builder notificationBuilder =
         createNotificationBuilder(context, smallIcon, channelId, message, titleStringId);
 
+    int progress = haveDownloadTasks ? (int) (totalPercentage / downloadTaskCount) : 0;
+    boolean indeterminate = allDownloadPercentagesUnknown && haveDownloadedBytes;
+    notificationBuilder.setProgress(/* max= */ 100, progress, indeterminate);
     notificationBuilder.setOngoing(true);
-    int max = 100;
-    int progress = (int) (totalPercentage / determinatePercentageCount);
-    boolean indeterminate = determinatePercentageCount == 0;
-    notificationBuilder.setProgress(max, progress, indeterminate);
-
     notificationBuilder.setShowWhen(false);
     return notificationBuilder.build();
   }