如何阻止android通知重复

NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.cancel(notificationId);

NotificationCompat.Builder builder = new NotificationCompat.Builder(context)
        .setOnlyAlertOnce(true)
        .setContentTitle("Title")
        .setContentText("Content");

NotificationManager notificationManager = getSystemService(NotificationManager.class);

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    String channelId = "channel_id";
    CharSequence channelName = "channel_name";
    String channelDescription = "channel_description";

    int importance = NotificationManager.IMPORTANCE_DEFAULT;

    NotificationChannel channel = new NotificationChannel(channelId, channelName, importance);
    channel.setDescription(channelDescription);

    channel.setSound(null, null); // 不发出响铃
    channel.enableVibration(false); // 不震动
    channel.enableLights(false); // 不闪光

    notificationManager.createNotificationChannel(channel);
}