android设置音量（话音）

设置音量（am.setStreamVolume(AudioManager.STREAM_VOICE_CALL, 0, AudioManager.FLAG_SHOW_UI);）： 
发送广播通知： 
Intent intent = new Intent(AudioManager.VOLUME_CHANGED_ACTION); 
        intent.putExtra(AudioManager.EXTRA_VOLUME_STREAM_TYPE, streamType); 
        intent.putExtra(AudioManager.EXTRA_VOLUME_STREAM_VALUE, index); 
        intent.putExtra(AudioManager.EXTRA_PREV_VOLUME_STREAM_VALUE, oldIndex); 

        mContext.sendBroadcast(intent); 

UI： 
即使音量设为0,通话也有声音：VolumePanel.java: 
case AudioManager.STREAM_VOICE_CALL: { 
                /* 
                 * For in-call voice call volume, there is no inaudible volume. 
                 * Rescale the UI control so the progress bar doesn't go all 
                 * the way to zero and don't show the mute icon. 
                 */ 
                index++;  // 音量由0变为1了 
                max++; 
                message = INCALL_VOLUME_TEXT; 
                setSmallIcon(index); 
                break; 
            } 
(end)