If you are looking to apply the big view style to a notification, here is the solution you are looking for:-

Uri notificationsound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
String notificationText;
NotificationManager mNotificationManager;
int  NOTIFICATION_ID;

notificationText = "This is the notification long message "+
                   "that will cover more than two lines in the notification." +
                   "This is just the part of our example " ;

NOTIFICATION_ID = (int) (System.currentTimeMillis());

mNotificationManager = (NotificationManager)
                this.getSystemService(Context.NOTIFICATION_SERVICE);

final Notification.Builder builder = new Notification.Builder(this);
builder.setStyle(new Notification.BigTextStyle(builder)
            .bigText(notificationText)
            .setBigContentTitle("NotificationTitle")
            .setSummaryText("Big summary"))
            .setContentTitle("Title")
            .setContentText("Hello this is the context text")
            .setSmallIcon(R.drawable.logo);

mNotificationManager.notify(NOTIFICATION_ID, mBuilder.build());