Fix A11y volume persisting/restore

When the accessibility volume is enabled, its value wasn't persisted
  when changed because it was still using the persisting name from
  its alias (music).
When enabled, notiify the volume controller that a11y volume has
  changed so the UI also reflects the new value, now updated from
  the persisted settings.
Do not persist volumes for streams that don't have a setting name.

Test: enable Talkback, set a11y volume at a different level than media \
  then disable Talkback. Reboot and enable Talkback, verify a11y is \
  restored.
Bug: 36286073

Change-Id: Ic6c30364e164b856fc10fbf6b22c09a7b5561be1

2 files changed, 60 insertions, 14 deletions

diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 287ab9ecdf51..73a8592d176d 100755
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -3150,6 +3150,13 @@ public final class Settings {
         public static final String VOLUME_BLUETOOTH_SCO = "volume_bluetooth_sco";
 
         /**
+         * @hide
+         * Acessibility volume. This is used internally, changing this
+         * value will not change the volume.
+         */
+        public static final String VOLUME_ACCESSIBILITY = "volume_a11y";
+
+        /**
          * Master volume (float in the range 0.0f to 1.0f).
          *
          * @hide
@@ -3212,6 +3219,22 @@ public final class Settings {
         };
 
         /**
+         * @hide
+         * The mapping of stream type (integer) to its setting.
+         * Unlike the VOLUME_SETTINGS array, this one contains as many entries as
+         * AudioSystem.NUM_STREAM_TYPES, and has empty strings for stream types whose volumes
+         * are never persisted.
+         */
+        public static final String[] VOLUME_SETTINGS_INT = {
+                VOLUME_VOICE, VOLUME_SYSTEM, VOLUME_RING, VOLUME_MUSIC,
+                VOLUME_ALARM, VOLUME_NOTIFICATION, VOLUME_BLUETOOTH_SCO,
+                "" /*STREAM_SYSTEM_ENFORCED, no setting for this stream*/,
+                "" /*STREAM_DTMF, no setting for this stream*/,
+                "" /*STREAM_TTS, no setting for this stream*/,
+                VOLUME_ACCESSIBILITY
+            };
+
+        /**
          * Appended to various volume related settings to record the previous
          * values before they the settings were affected by a silent/vibrate
          * ringer mode change.
diff --git a/services/core/java/com/android/server/audio/AudioService.java b/services/core/java/com/android/server/audio/AudioService.java
index c11f5316f769..268724283351 100644
--- a/services/core/java/com/android/server/audio/AudioService.java
+++ b/services/core/java/com/android/server/audio/AudioService.java
@@ -23,6 +23,7 @@ import static android.media.AudioManager.RINGER_MODE_VIBRATE;
 import static android.os.Process.FIRST_APPLICATION_UID;
 
 import android.Manifest;
+import android.annotation.Nullable;
 import android.app.ActivityManager;
 import android.app.ActivityManagerInternal;
 import android.app.AppGlobals;
@@ -968,7 +969,8 @@ public class AudioService extends IAudioService.Stub
         VolumeStreamState[] streams = mStreamStates = new VolumeStreamState[numStreamTypes];
 
         for (int i = 0; i < numStreamTypes; i++) {
-            streams[i] = new VolumeStreamState(System.VOLUME_SETTINGS[mStreamVolumeAlias[i]], i);
+            streams[i] =
+                    new VolumeStreamState(System.VOLUME_SETTINGS_INT[mStreamVolumeAlias[i]], i);
         }
 
         checkAllFixedVolumeDevices();
@@ -1020,7 +1022,14 @@ public class AudioService extends IAudioService.Stub
         }
 
         mStreamVolumeAlias[AudioSystem.STREAM_DTMF] = dtmfStreamAlias;
-        mStreamVolumeAlias[AudioSystem.STREAM_ACCESSIBILITY] = a11yStreamAlias;
+        final int oldStreamA11yAlias = mStreamVolumeAlias[AudioSystem.STREAM_ACCESSIBILITY];
+        if (oldStreamA11yAlias != a11yStreamAlias) {
+            mStreamVolumeAlias[AudioSystem.STREAM_ACCESSIBILITY] = a11yStreamAlias;
+            mStreamStates[AudioSystem.STREAM_ACCESSIBILITY].mVolumeIndexSettingName =
+                    System.VOLUME_SETTINGS_INT[a11yStreamAlias];
+            // restore the value from the settings when the alias changes
+            mStreamStates[AudioSystem.STREAM_ACCESSIBILITY].readSettings();
+        }
 
         if (updateVolumes) {
             mStreamStates[AudioSystem.STREAM_DTMF].setAllIndexes(mStreamStates[dtmfStreamAlias],
@@ -3992,13 +4001,19 @@ public class AudioService extends IAudioService.Stub
             return devices;
         }
 
-        public String getSettingNameForDevice(int device) {
-            String name = mVolumeIndexSettingName;
-            String suffix = AudioSystem.getOutputDeviceName(device);
+        public @Nullable String getSettingNameForDevice(int device) {
+            if (!hasValidSettingsName()) {
+                return null;
+            }
+            final String suffix = AudioSystem.getOutputDeviceName(device);
             if (suffix.isEmpty()) {
-                return name;
+                return mVolumeIndexSettingName;
             }
-            return name + "_" + suffix;
+            return mVolumeIndexSettingName + "_" + suffix;
+        }
+
+        private boolean hasValidSettingsName() {
+            return (mVolumeIndexSettingName != null && !mVolumeIndexSettingName.isEmpty());
         }
 
         public void readSettings() {
@@ -4033,13 +4048,18 @@ public class AudioService extends IAudioService.Stub
                     remainingDevices &= ~device;
 
                     // retrieve current volume for device
-                    String name = getSettingNameForDevice(device);
                     // if no volume stored for current stream and device, use default volume if default
                     // device, continue otherwise
                     int defaultIndex = (device == AudioSystem.DEVICE_OUT_DEFAULT) ?
                             AudioSystem.DEFAULT_STREAM_VOLUME[mStreamType] : -1;
-                    int index = Settings.System.getIntForUser(
-                            mContentResolver, name, defaultIndex, UserHandle.USER_CURRENT);
+                    int index;
+                    if (!hasValidSettingsName()) {
+                        index = defaultIndex;
+                    } else {
+                        String name = getSettingNameForDevice(device);
+                        index = Settings.System.getIntForUser(
+                                mContentResolver, name, defaultIndex, UserHandle.USER_CURRENT);
+                    }
                     if (index == -1) {
                         continue;
                     }
@@ -4420,10 +4440,12 @@ public class AudioService extends IAudioService.Stub
             if (mIsSingleVolume && (streamState.mStreamType != AudioSystem.STREAM_MUSIC)) {
                 return;
             }
-            System.putIntForUser(mContentResolver,
-                      streamState.getSettingNameForDevice(device),
-                      (streamState.getIndex(device) + 5)/ 10,
-                      UserHandle.USER_CURRENT);
+            if (streamState.hasValidSettingsName()) {
+                System.putIntForUser(mContentResolver,
+                        streamState.getSettingNameForDevice(device),
+                        (streamState.getIndex(device) + 5)/ 10,
+                        UserHandle.USER_CURRENT);
+            }
         }
 
         private void persistRingerMode(int ringerMode) {
@@ -6059,6 +6081,7 @@ public class AudioService extends IAudioService.Stub
             mVolumeController.setA11yMode(sIndependentA11yVolume ?
                     VolumePolicy.A11Y_MODE_INDEPENDENT_A11Y_VOLUME :
                         VolumePolicy.A11Y_MODE_MEDIA_A11Y_VOLUME);
+            mVolumeController.postVolumeChanged(AudioManager.STREAM_ACCESSIBILITY, 0);
         }
     }