Java Android中的通知代码

我试图在一个按钮中编写一个简单的通知代码，当我按下按钮时，它会创建一个通知，但当我按下按钮时，通知不会出现。这是我正在使用的代码

int notificationId = 001;
        // Build intent for notification content
        Intent viewIntent = new Intent(SessionsActivity.this, MainActivity.class);
        PendingIntent viewPendingIntent =
                PendingIntent.getActivity(SessionsActivity.this, 0, viewIntent, 0);
        NotificationCompat.Builder notificationBuilder =
                new NotificationCompat.Builder(SessionsActivity.this)
                        .setContentTitle("hii")
                        .setContentText("hii2")
                        .setContentIntent(viewPendingIntent);
        // Get an instance of the NotificationManager service
        NotificationManagerCompat notificationManager =NotificationManagerCompat.from(SessionsActivity.this);
        // Build the notification and issues it with notification manager.
        notificationManager.notify(notificationId, notificationBuilder.build());

Intent viewIntent = new Intent(SessionsActivity.this, MainActivity.class);

PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, viewIntent , PendingIntent.FLAG_UPDATE_CURRENT);
Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
        .setSmallIcon(R.drawable.ic_launcher)
        .setContentTitle(getResources().getString(R.string.app_name))
        .setAutoCancel(true)
        .setSound(defaultSoundUri)
        .setContentIntent(pendingIntent);


NotificationCompat.InboxStyle inboxStyle = new NotificationCompat.InboxStyle();
notificationBuilder.setStyle(inboxStyle);
inboxStyle.setBigContentTitle("sdjshfjnds");
inboxStyle.addLine("sdjjsdfn");
notificationBuilder.setStyle(inboxStyle);

NotificationManager notificationManager =
        (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
int NOTIFICATION_ID = 100;
notificationManager.notify(NOTIFICATION_ID, notificationBuilder.build());