Bug 5567648 Request and abandon audio focus in calls

Up to now, audio focus was implicitly requested and abandoned
 when changing the audio mode. This is no longer the case so the
 behavior with regards to audio focus can be indepently set by
 the CallManager.
The logic implemented here is the same as the one previously used
 in AudioService:
  - only request audio focus when the ring volume index is > 0
    when ringing,
  - request focus before setting the audio mode to a mode other
    than normal
  - abandon audio focus after setting the audio mode to normal

Change-Id: Ia543dc779563dbff09414771fee60e589dfaab9d

Author: jmtrivi

telephony/java/com/android/internal/telephony/CallManager.java

@@ -373,10 +373,19 @@ public void setAudioMode() {
         AudioManager audioManager = (AudioManager)
                 context.getSystemService(Context.AUDIO_SERVICE);
 
-        int mode = AudioManager.MODE_NORMAL;
+        // change the audio mode and request/abandon audio focus according to phone state,
+        // but only on audio mode transitions
         switch (getState()) {
             case RINGING:
-                mode = AudioManager.MODE_RINGTONE;
+                if (audioManager.getMode() != AudioManager.MODE_RINGTONE) {
+                    // only request audio focus if the ringtone is going to be heard
+                    if (audioManager.getStreamVolume(AudioManager.STREAM_RING) > 0) {
+                        if (VDBG) Log.d(LOG_TAG, "requestAudioFocus on STREAM_RING");
+                        audioManager.requestAudioFocusForCall(AudioManager.STREAM_RING,
+                                AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
+                    }
+                    audioManager.setMode(AudioManager.MODE_RINGTONE);
+                }
                 break;
             case OFFHOOK:
                 Phone offhookPhone = getFgPhone();
@@ -386,18 +395,28 @@ public void setAudioMode() {
                     offhookPhone = getBgPhone();
                 }
 
+                int newAudioMode = AudioManager.MODE_IN_CALL;
                 if (offhookPhone instanceof SipPhone) {
-                    // enable IN_COMMUNICATION audio mode for sipPhone
-                    mode = AudioManager.MODE_IN_COMMUNICATION;
-                } else {
-                    // enable IN_CALL audio mode for telephony
-                    mode = AudioManager.MODE_IN_CALL;
+                    // enable IN_COMMUNICATION audio mode instead for sipPhone
+                    newAudioMode = AudioManager.MODE_IN_COMMUNICATION;
+                }
+                if (audioManager.getMode() != newAudioMode) {
+                    // request audio focus before setting the new mode
+                    if (VDBG) Log.d(LOG_TAG, "requestAudioFocus on STREAM_VOICE_CALL");
+                    audioManager.requestAudioFocusForCall(AudioManager.STREAM_VOICE_CALL,
+                            AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
+                    audioManager.setMode(newAudioMode);
+                }
+                break;
+            case IDLE:
+                if (audioManager.getMode() != AudioManager.MODE_NORMAL) {
+                    audioManager.setMode(AudioManager.MODE_NORMAL);
+                    if (VDBG) Log.d(LOG_TAG, "abandonAudioFocus");
+                    // abandon audio focus after the mode has been set back to normal
+                    audioManager.abandonAudioFocusForCall();
                 }
                 break;
         }
-        // calling audioManager.setMode() multiple times in a short period of
-        // time seems to break the audio recorder in in-call mode
-        if (audioManager.getMode() != mode) audioManager.setMode(mode);
     }
 
     private Context getContext() {