两个问题：

1.直播过程中，如果接听电话，那么需要将直播声音关闭，电话挂断，需要恢复到原声音大小

2.直播过程中，按Home键退到桌面（后台还在继续直播，还能听到声音），需要在状态栏显示通知xxx正在直播

第一个需要监听广播

private AudioManager audioMgr = null; // Audio管理器，用了控制音量
    private int maxVolume; // 最大音量值

    private int currentVolume;//当前音量值
    private void changeVoice()
    {
        audioMgr = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
        // 获取最大音乐音量
        maxVolume = audioMgr.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
        if (android.os.Build.VERSION.SDK_INT >= 21) {

            requestPhoneAccess();
        }
        else
        {
            initPhone();
        }


    }


    private void getCurrentVoice()
    {
        currentVolume =audioMgr.getStreamVolume(AudioManager.STREAM_MUSIC);
        Log.e("abc--->最大音量------》",maxVolume+"当前音量----->"+currentVolume);
    }
    class EncryptPhoneStateListener extends PhoneStateListener {

        EncryptPhoneStateListener() {

        }

        public void onCallStateChanged(int state, String incomingNumber) {
            switch (state) {
                case TelephonyManager.CALL_STATE_OFFHOOK:// 拨打电话或者接听电话时
                    audioMgr.setStreamVolume(AudioManager.STREAM_MUSIC, 0,
                            AudioManager.FLAG_PLAY_SOUND);
                    break;
                case TelephonyManager.CALL_STATE_RINGING:// 电话进来时
                    audioMgr.setStreamVolume(AudioManager.STREAM_MUSIC, 0,
                            AudioManager.FLAG_PLAY_SOUND);
                    break;
                case TelephonyManager.CALL_STATE_IDLE:// 挂起电话时候，或者没有任何反映
                    audioMgr.setStreamVolume(AudioManager.STREAM_MUSIC, currentVolume,
                            AudioManager.FLAG_PLAY_SOUND);
                    break;
                default:
                    break;
            }
        }
    }

private  void initPhone()
    {
        TelephonyManager telephonyManager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
        // 开始监听
        PhoneStateListener phoneListener = new EncryptPhoneStateListener();
        telephonyManager.listen(phoneListener, PhoneStateListener.LISTEN_CALL_STATE);
        getCurrentVoice();
    }

/**
     * 申请电话状态
     */
    private void requestPhoneAccess() {
        if (!(ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) == PackageManager.PERMISSION_GRANTED)) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_PHONE_STATE, Manifest.permission.CALL_PHONE,Manifest.permission.PROCESS_OUTGOING_CALLS}, REQUEST_PHONE_CODE);
        }
        else
        {
            initPhone();
        }
    }

入口：调用changeVoice();

第二个需要监听home键广播

private NotificationManager notificationManager;
    private Notification notification;

    @SuppressLint("NewApi")
    public void sendnotification() {
        if (notificationManager == null) {
            notificationManager = (NotificationManager)
                    getSystemService(Context.NOTIFICATION_SERVICE);
        }
        Intent notificationIntent = new Intent(this, LiveActivity.class);
        notificationIntent.putExtra("videoinfo",reservation);
        notificationIntent.putExtra("videowidht", videoWidht);
        notificationIntent.putExtra("videoheight", videoHeight);
        PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
                notificationIntent, 0);
        // ③ 定义notification的消息 和 PendingIntent
        if (android.os.Build.VERSION.SDK_INT >= 16) {
            notification = new Notification.Builder(this)
                    .setAutoCancel(true).setContentTitle("米多财富")
                    .setContentText("米多财富正在直播......")
                    .setContentIntent(contentIntent)
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .setWhen(System.currentTimeMillis()).build();
        } else {
            Notification.Builder builder = new Notification.Builder(this)
                    .setAutoCancel(true).setContentTitle("米多财富")
                    .setContentText("米多财富正在直播......").setContentIntent(contentIntent)
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .setWhen(System.currentTimeMillis()).setOngoing(true);
            notification = builder.getNotification();

        }
        notificationManager.notify(getNotificationId(this), notification);
    }

    private int notyfyid;
    /**
     * 从配置文件中获取通知id（id为累加，防止重复）
     *
     * @return
     */
    public int getNotificationId(Context context) {
        id = SharePrefUtil.getInt(context, "NOTIFICATION_ID", 0);
        int tempid = ++id;
        SharePrefUtil.saveInt(context, "NOTIFICATION_ID", tempid > 1000 ? 0
                : tempid);
        notyfyid=id;
        return id;
    }


    /*
    *监听是否点击了home键将客户端推到后台
    */
    private BroadcastReceiver mHomeKeyEventReceiver = new BroadcastReceiver() {
        String SYSTEM_REASON = "reason";
        String SYSTEM_HOME_KEY = "homekey";
        String SYSTEM_HOME_KEY_LONG = "recentapps";
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
                String reason = intent.getStringExtra(SYSTEM_REASON);
                if (TextUtils.equals(reason, SYSTEM_HOME_KEY)) {
                    //表示按了home键,程序到了后台
                    try {
                        sendnotification();
                    }
                    catch (Exception e)
                    {

                    }

                }else if(TextUtils.equals(reason, SYSTEM_HOME_KEY_LONG)){
                    //表示长按home键,显示最近使用的程序列表
                }
            }
        }
    };

注册广播：

 registerReceiver(mHomeKeyEventReceiver, new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS));

反注册广播：

unregisterReceiver(mHomeKeyEventReceiver);
                mHomeKeyEventReceiver=null;