provide content description for the player view to make show/hide controls accessible

PiperOrigin-RevId: 274148026

RELEASENOTES.md

@@ -110,6 +110,7 @@
 * Add `MediaPeriod.isLoading` to improve `Player.isLoading` state.
 * Add support for ID3-in-EMSG in HLS streams
   ([spec](https://aomediacodec.github.io/av1-id3/)).
+* Make show and hide player controls accessible for TalkBack in `PlayerView`.
 
 ### 2.10.5 (2019-09-20) ###
 

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

@@ -43,6 +43,7 @@ import com.google.android.exoplayer2.util.Util;
 import java.util.Arrays;
 import java.util.Formatter;
 import java.util.Locale;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
  * A view for controlling {@link Player} instances.
@@ -231,6 +232,7 @@ public class PlayerControlView extends FrameLayout {
   private static final int MAX_UPDATE_INTERVAL_MS = 1000;
 
   private final ComponentListener componentListener;
+  private final CopyOnWriteArrayList<VisibilityListener> visibilityListeners;
   private final View previousButton;
   private final View nextButton;
   private final View playButton;
@@ -265,7 +267,6 @@ public class PlayerControlView extends FrameLayout {
 
   @Nullable private Player player;
   private com.google.android.exoplayer2.ControlDispatcher controlDispatcher;
-  @Nullable private VisibilityListener visibilityListener;
   @Nullable private ProgressUpdateListener progressUpdateListener;
   @Nullable private PlaybackPreparer playbackPreparer;
 
@@ -335,6 +336,7 @@ public class PlayerControlView extends FrameLayout {
         a.recycle();
       }
     }
+    visibilityListeners = new CopyOnWriteArrayList<>();
     period = new Timeline.Period();
     window = new Timeline.Window();
     formatBuilder = new StringBuilder();
@@ -510,13 +512,21 @@ public class PlayerControlView extends FrameLayout {
   }
 
   /**
-   * Sets the {@link VisibilityListener}.
+   * Adds a {@link VisibilityListener}.
    *
-   * @param listener The listener to be notified about visibility changes, or null to remove the
+   * @param listener The listener to be notified about visibility changes.
-   *     current listener.
    */
-  public void setVisibilityListener(@Nullable VisibilityListener listener) {
+  public void addVisibilityListener(VisibilityListener listener) {
-    this.visibilityListener = listener;
+    visibilityListeners.add(listener);
+  }
+
+  /**
+   * Removes a {@link VisibilityListener}.
+   *
+   * @param listener The listener to be removed.
+   */
+  public void removeVisibilityListener(VisibilityListener listener) {
+    visibilityListeners.remove(listener);
   }
 
   /**
@@ -697,7 +707,7 @@ public class PlayerControlView extends FrameLayout {
   public void show() {
     if (!isVisible()) {
       setVisibility(VISIBLE);
-      if (visibilityListener != null) {
+      for (VisibilityListener visibilityListener : visibilityListeners) {
         visibilityListener.onVisibilityChange(getVisibility());
       }
       updateAll();
@@ -711,7 +721,7 @@ public class PlayerControlView extends FrameLayout {
   public void hide() {
     if (isVisible()) {
       setVisibility(GONE);
-      if (visibilityListener != null) {
+      for (VisibilityListener visibilityListener : visibilityListeners) {
         visibilityListener.onVisibilityChange(getVisibility());
       }
       removeCallbacks(updateProgressAction);

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

@@ -294,6 +294,7 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
 
   private Player player;
   private boolean useController;
+  @Nullable private PlayerControlView.VisibilityListener controllerVisibilityListener;
   private boolean useArtwork;
   @Nullable private Drawable defaultArtwork;
   private @ShowBuffering int showBuffering;
@@ -483,6 +484,10 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
     this.controllerHideDuringAds = controllerHideDuringAds;
     this.useController = useController && controller != null;
     hideController();
+    updateContentDescription();
+    if (controller != null) {
+      controller.addVisibilityListener(/* listener= */ componentListener);
+    }
   }
 
   /**
@@ -687,8 +692,9 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
       controller.setPlayer(player);
     } else if (controller != null) {
       controller.hide();
-      controller.setPlayer(null);
+      controller.setPlayer(/* player= */ null);
     }
+    updateContentDescription();
   }
 
   /**
@@ -880,6 +886,7 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
   public void setControllerHideOnTouch(boolean controllerHideOnTouch) {
     Assertions.checkState(controller != null);
     this.controllerHideOnTouch = controllerHideOnTouch;
+    updateContentDescription();
   }
 
   /**
@@ -921,7 +928,16 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
   public void setControllerVisibilityListener(
       @Nullable PlayerControlView.VisibilityListener listener) {
     Assertions.checkState(controller != null);
-    controller.setVisibilityListener(listener);
+    if (this.controllerVisibilityListener == listener) {
+      return;
+    }
+    if (this.controllerVisibilityListener != null) {
+      controller.removeVisibilityListener(this.controllerVisibilityListener);
+    }
+    this.controllerVisibilityListener = listener;
+    if (listener != null) {
+      controller.addVisibilityListener(listener);
+    }
   }
 
   /**
@@ -1359,6 +1375,20 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
     }
   }
 
+  private void updateContentDescription() {
+    if (controller == null || !useController) {
+      setContentDescription(/* contentDescription= */ null);
+    } else if (controller.getVisibility() == View.VISIBLE) {
+      setContentDescription(
+          /* contentDescription= */ controllerHideOnTouch
+              ? getResources().getString(R.string.exo_controls_hide)
+              : null);
+    } else {
+      setContentDescription(
+          /* contentDescription= */ getResources().getString(R.string.exo_controls_show));
+    }
+  }
+
   @TargetApi(23)
   private static void configureEditModeLogoV23(Resources resources, ImageView logo) {
     logo.setImageDrawable(resources.getDrawable(R.drawable.exo_edit_mode_logo, null));
@@ -1418,7 +1448,8 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
           TextOutput,
           VideoListener,
           OnLayoutChangeListener,
-          SingleTapListener {
+          SingleTapListener,
+          PlayerControlView.VisibilityListener {
 
     // TextOutput implementation
 
@@ -1513,5 +1544,12 @@ public class PlayerView extends FrameLayout implements AdsLoader.AdViewProvider
     public boolean onSingleTapUp(MotionEvent e) {
       return toggleControllerVisibility();
     }
+
+    // PlayerControlView.VisibilityListener implementation
+
+    @Override
+    public void onVisibilityChange(int visibility) {
+      updateContentDescription();
+    }
   }
 }

library/ui/src/main/res/values/strings.xml

@@ -14,6 +14,10 @@
      limitations under the License.
 -->
 <resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+  <!-- Description for a media player view to indicate that tapping on the view shows the playback controls. [CHAR LIMIT=50] -->
+  <string name="exo_controls_show">Show player controls</string>
+  <!-- Description for a media player view to indicate that tapping on the view hides the playback controls [CHAR LIMIT=50] -->
+  <string name="exo_controls_hide">Hide player controls</string>
   <!-- Description for a media control button that causes the previous track to be played. [CHAR LIMIT=30] -->
   <string name="exo_controls_previous_description">Previous track</string>
   <!-- Description for a media control button that causes the next track to be played. [CHAR LIMIT=30] -->