1.在创建Notification时指定通知的声音为null：

NotificationCompat.Builder builder = new NotificationCompat.Builder(context, channelId)
        .setSmallIcon(R.drawable.notification_icon)
        .setContentTitle("My Notification")
        .setContentText("This is the content of my notification")
        .setPriority(NotificationCompat.PRIORITY_DEFAULT)
        .setSound(null);
NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);
notificationManager.notify(notificationId, builder.build());

2.使用setDefaults()方法，并设置默认声音为NONE：

NotificationCompat.Builder builder = new NotificationCompat.Builder(context, channelId)
        .setSmallIcon(R.drawable.notification_icon)
        .setContentTitle("My Notification")
        .setContentText("This is the content of my notification")
        .setPriority(NotificationCompat.PRIORITY_DEFAULT)
        .setDefaults(NotificationCompat.DEFAULT_NONE);
NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);
notificationManager.notify(notificationId, builder.build());

使用以上任意一种方法，都可以创建一个禁音但是仍然在屏幕弹出的通知。