Tie the lockscreen sounds with the ringer volume.

Actual volume is a ratio of the ringer volume and drops along with
but slower than the ringer volume, so that at lowest ringer volume,
the lockscreen sounds are still somewhat audible.

Don't start the sounds if the ringer is muted.

Bug: 5394473
Change-Id: Ifcf242b3198b4ec8f12334e26ec23ebf05a96b83

Author: Amith Yamasani

policy/src/com/android/internal/policy/impl/KeyguardViewMediator.java

@@ -147,8 +147,16 @@ public class KeyguardViewMediator implements KeyguardViewCallback,
      */
     private static final boolean ENABLE_INSECURE_STATUS_BAR_EXPAND = true;
 
+    /** The stream type that the lock sounds are tied to. */
+    private static final int MASTER_STREAM_TYPE = AudioManager.STREAM_RING;
+    /** Minimum volume for lock sounds, as a ratio of max MASTER_STREAM_TYPE */
+    final float MIN_LOCK_VOLUME = 0.05f;
+    /** Maximum volume for lock sounds, as a ratio of max MASTER_STREAM_TYPE */
+    final float MAX_LOCK_VOLUME = 0.4f;
+
     private Context mContext;
     private AlarmManager mAlarmManager;
+    private AudioManager mAudioManager;
     private StatusBarManager mStatusBarManager;
     private boolean mShowLockIcon;
     private boolean mShowingLockIcon;
@@ -255,6 +263,7 @@ public class KeyguardViewMediator implements KeyguardViewCallback,
     private int mLockSoundId;
     private int mUnlockSoundId;
     private int mLockSoundStreamId;
+    private int mMasterStreamMaxVolume;
 
     public KeyguardViewMediator(Context context, PhoneWindowManager callback,
             LocalPowerManager powerManager) {
@@ -1061,13 +1070,33 @@ private void playSounds(boolean locked) {
         }
 
         final ContentResolver cr = mContext.getContentResolver();
-        if (Settings.System.getInt(cr, Settings.System.LOCKSCREEN_SOUNDS_ENABLED, 1) == 1)
-        {
+        if (Settings.System.getInt(cr, Settings.System.LOCKSCREEN_SOUNDS_ENABLED, 1) == 1) {
             final int whichSound = locked
                 ? mLockSoundId
                 : mUnlockSoundId;
             mLockSounds.stop(mLockSoundStreamId);
-            mLockSoundStreamId = mLockSounds.play(whichSound, 1.0f, 1.0f, 1, 0, 1.0f);
+            // Init mAudioManager
+            if (mAudioManager == null) {
+                mAudioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);
+                if (mAudioManager == null) return;
+                mMasterStreamMaxVolume = mAudioManager.getStreamMaxVolume(MASTER_STREAM_TYPE);
+            }
+            // If the stream is muted, don't play the sound
+            if (mAudioManager.isStreamMute(MASTER_STREAM_TYPE)) return;
+
+            // Adjust the lock sound volume from a minimum of MIN_LOCK_VOLUME to a maximum
+            // of MAX_LOCK_VOLUME, relative to the maximum level of the MASTER_STREAM_TYPE volume.
+            float lockSoundVolume;
+            int masterStreamVolume = mAudioManager.getStreamVolume(MASTER_STREAM_TYPE);
+            if (masterStreamVolume == 0) {
+                return;
+            } else {
+                lockSoundVolume = MIN_LOCK_VOLUME + (MAX_LOCK_VOLUME - MIN_LOCK_VOLUME)
+                        * ((float) masterStreamVolume / mMasterStreamMaxVolume);
+            }
+
+            mLockSoundStreamId = mLockSounds.play(whichSound, lockSoundVolume, lockSoundVolume, 1,
+                    0, 1.0f);
         }
     }