startForeground中id设置为0后，startForeground无效

我startForeground的id设置为0后，一开始是可以探出通知的，但是后来就没反应了。如果把0改成其他数字，startForeground是好用的，有人知道是什么原因吗？

                createNotificationChanel("alarm");
                Calendar calendar=Calendar.getInstance();
                NotificationManager notificationManager=(NotificationManager) getSystemService(NOTIFICATION_SERVICE);
                notificationManager.cancelAll();
                Notification notification=new NotificationCompat.Builder(this,"alarm")
                        .setSmallIcon(R.mipmap.ic_launcher_round)
                        .setLargeIcon(BitmapFactory.decodeResource(getResources(),R.mipmap.ic_launcher_round))
                        .setContentTitle("闹钟")
                        .setContentText("7:00")
                        .setSound(Uri.parse("android.resource://"+getApplicationContext().getPackageName()+
                                "/"+R.raw.bell))
                        .setPriority(NotificationCompat.PRIORITY_MAX)
                        .setWhen(calendar.getTimeInMillis())
                        .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
                        .build();
                LogInfo.d("****startForeground ");
                startForeground(0,notification);

createNotificationChanel的定义如下

    private void createNotificationChanel( String chanelID){
        LogInfo.d("createNotificationChanel start");
        // Create the NotificationChannel, but only on API 26+ because
        // the NotificationChannel class is new and not in the support library
        //创建通知渠道的代码只在第一次执行的时候才会创建，以后每次执行创建代码系统会检测到该通知渠道已经存在了，因此不会重复创建
        if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.O){
            String channelName="闹钟";
            String description="允许闹钟响应";
            int importance= NotificationManager.IMPORTANCE_HIGH;
            NotificationChannel channel=new NotificationChannel(chanelID,channelName,importance);
            channel.setDescription(description);
            NotificationManager notificationManager=getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }
    }