Show toast if media contains only unplayable audio/video.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=123885817

demo/src/main/java/com/google/android/exoplayer/demo/PlayerActivity.java

@@ -235,8 +235,7 @@ public class PlayerActivity extends Activity implements SurfaceHolder.Callback,
     if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
       initializePlayer();
     } else {
-      Toast.makeText(getApplicationContext(), R.string.storage_permission_denied,
-          Toast.LENGTH_LONG).show();
+      showToast(R.string.storage_permission_denied);
       finish();
     }
   }
@@ -330,10 +329,10 @@ public class PlayerActivity extends Activity implements SurfaceHolder.Callback,
   }
 
   private void onUnsupportedDrmError(UnsupportedDrmException e) {
-    String errorString = getString(Util.SDK_INT < 18 ? R.string.error_drm_not_supported
+    int errorStringId = Util.SDK_INT < 18 ? R.string.error_drm_not_supported
         : e.reason == UnsupportedDrmException.REASON_UNSUPPORTED_SCHEME
-        ? R.string.error_drm_unsupported_scheme : R.string.error_drm_unknown);
-    Toast.makeText(getApplicationContext(), errorString, Toast.LENGTH_LONG).show();
+        ? R.string.error_drm_unsupported_scheme : R.string.error_drm_unknown;
+    showToast(errorStringId);
   }
 
   /**
@@ -416,7 +415,7 @@ public class PlayerActivity extends Activity implements SurfaceHolder.Callback,
       }
     }
     if (errorString != null) {
-      Toast.makeText(getApplicationContext(), errorString, Toast.LENGTH_LONG).show();
+      showToast(errorString);
     }
     playerNeedsSource = true;
     updateButtonVisibilities();
@@ -440,8 +439,24 @@ public class PlayerActivity extends Activity implements SurfaceHolder.Callback,
   // DefaultTrackSelector.EventListener implementation
 
   @Override
-  public void onTracksChanged(TrackInfo trackSet) {
+  public void onTracksChanged(TrackInfo trackInfo) {
     updateButtonVisibilities();
+    // Print toasts if there exist only unplayable video or audio tracks.
+    int videoRendererSupport = TrackInfo.RENDERER_SUPPORT_NO_TRACKS;
+    int audioRendererSupport = TrackInfo.RENDERER_SUPPORT_NO_TRACKS;
+    for (int i = 0; i < trackInfo.rendererCount; i++) {
+      if (player.getRendererType(i) == C.TRACK_TYPE_VIDEO) {
+        videoRendererSupport = Math.max(videoRendererSupport, trackInfo.getRendererSupport(i));
+      } else if (player.getRendererType(i) == C.TRACK_TYPE_AUDIO) {
+        audioRendererSupport = Math.max(audioRendererSupport, trackInfo.getRendererSupport(i));
+      }
+    }
+    if (videoRendererSupport == TrackInfo.RENDERER_SUPPORT_UNPLAYABLE_TRACKS) {
+      showToast(R.string.error_unsupported_video);
+    }
+    if (audioRendererSupport == TrackInfo.RENDERER_SUPPORT_UNPLAYABLE_TRACKS) {
+      showToast(R.string.error_unsupported_audio);
+    }
   }
 
   // User controls
@@ -573,6 +588,14 @@ public class PlayerActivity extends Activity implements SurfaceHolder.Callback,
     return CaptionStyleCompat.createFromCaptionStyle(captioningManager.getUserStyle());
   }
 
+  private void showToast(int messageId) {
+    showToast(getString(messageId));
+  }
+
+  private void showToast(String message) {
+    Toast.makeText(getApplicationContext(), message, Toast.LENGTH_LONG).show();
+  }
+
   private static final class KeyCompatibleMediaController extends MediaController {
 
     private MediaController.MediaPlayerControl playerControl;

demo/src/main/res/values/strings.xml

@@ -47,6 +47,10 @@
 
   <string name="error_instantiating_decoder">Unable to instantiate decoder <xliff:g id="decoder_name">%1$s</xliff:g></string>
 
+  <string name="error_unsupported_video">Media includes video tracks, but none are playable by this device</string>
+
+  <string name="error_unsupported_audio">Media includes audio tracks, but none are playable by this device</string>
+
   <string name="storage_permission_denied">Permission to access storage was denied</string>
 
   <string name="sample_list_load_error">One or more sample lists failed to load</string>

library/src/main/java/com/google/android/exoplayer/DefaultTrackSelector.java

@@ -428,6 +428,19 @@ public final class DefaultTrackSelector extends TrackSelector implements
   public static final class TrackInfo {
 
     /**
+     * The renderer does not have any associated tracks.
+     */
+    public static final int RENDERER_SUPPORT_NO_TRACKS = 0;
+    /**
+     * The renderer has associated tracks, but cannot play any of them.
+     */
+    public static final int RENDERER_SUPPORT_UNPLAYABLE_TRACKS = 1;
+    /**
+     * The renderer has associated tracks, and can play at least one of them.
+     */
+    public static final int RENDERER_SUPPORT_PLAYABLE_TRACKS = 2;
+
+    /**
      * The number of renderers.
      */
     public final int rendererCount;
@@ -459,7 +472,7 @@ public final class DefaultTrackSelector extends TrackSelector implements
     }
 
     /**
-     * Gets the array of {@link TrackGroup}s that belong to the renderer at a specified index.
+     * Gets the array of {@link TrackGroup}s associated to the renderer at a specified index.
      *
      * @param rendererIndex The renderer index.
      * @return The corresponding {@link TrackGroup}s.
@@ -479,6 +492,28 @@ public final class DefaultTrackSelector extends TrackSelector implements
     }
 
     /**
+     * Gets the extent to which a renderer can support playback of the tracks associated to it.
+     *
+     * @param rendererIndex The renderer index.
+     * @return One of {@link #RENDERER_SUPPORT_PLAYABLE_TRACKS},
+     *     {@link #RENDERER_SUPPORT_UNPLAYABLE_TRACKS} and {@link #RENDERER_SUPPORT_NO_TRACKS}.
+     */
+    public int getRendererSupport(int rendererIndex) {
+      boolean hasTracks = false;
+      int[][] rendererFormatSupport = formatSupport[rendererIndex];
+      for (int i = 0; i < rendererFormatSupport.length; i++) {
+        for (int j = 0; j < rendererFormatSupport[i].length; j++) {
+          hasTracks = true;
+          if ((rendererFormatSupport[i][j] & TrackRenderer.FORMAT_SUPPORT_MASK)
+              == TrackRenderer.FORMAT_HANDLED) {
+            return RENDERER_SUPPORT_PLAYABLE_TRACKS;
+          }
+        }
+      }
+      return hasTracks ? RENDERER_SUPPORT_UNPLAYABLE_TRACKS : RENDERER_SUPPORT_NO_TRACKS;
+    }
+
+    /**
      * Gets the extent to which the format of an individual track is supported by the renderer.
      *
      * @param rendererIndex The renderer index.