Implement expand and collapse notification android

An expandable Notification is a special case of a Notification Big View. If the Big View is not at the top of the notification drawer, it it shown 'closed' and is expandable by swipe. Quote from Android Developers:

A notification's big view appears only when the notification is expanded, which happens when the notification is at the top of the notification drawer, or when the user expands the notification with a gesture. Expanded notifications are available starting with Android 4.1.

The Big View Notification can be created as follows:

Notification notification = new Notification.BigTextStyle(builder)
.bigText(myText).build();

or

Notification notification = new Notification.BigPictureStyle(builder)
.bigPicture(
  BitmapFactory.decodeResource(getResources(),
    R.drawable.my_picture)).build();

Here is a tutorial.

Notification noti = new Notification.Builder()
... // The same notification properties as the others
.setStyle(new Notification.BigPictureStyle().bigPicture(mBitmap))
.build();

You change

.setStyle(new NotificationCompat.BigTextStyle().bigText(th_alert))

along with the announcement OK !!!

notification = new NotificationCompat.Builder(context)

Here is an example:

Expandable Notifications and Notifications Groups

You can set Code

Intent intent = new Intent(context, ReserveStatusActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
NotificationManager notificationManager =
            (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
intent = new Intent(String.valueOf(PushActivity.class));
intent.putExtra("message", MESSAGE);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
stackBuilder.addParentStack(PushActivity.class);
stackBuilder.addNextIntent(intent);
// PendingIntent pendingIntent =
stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

// android.support.v4.app.NotificationCompat.BigTextStyle bigStyle = new     NotificationCompat.BigTextStyle();
// bigStyle.bigText((CharSequence) context);

notification = new NotificationCompat.Builder(context)
    .setSmallIcon(R.mipmap.ic_launcher)
    .setContentTitle(th_title)
    .setContentText(th_alert)
    .setAutoCancel(true)
 // .setStyle(new Notification.BigTextStyle().bigText(th_alert)  ตัวเก่า
 // .setStyle(new NotificationCompat.BigTextStyle().bigText(th_title))
    .setStyle(new NotificationCompat.BigTextStyle().bigText(th_alert))
    .setContentIntent(pendingIntent)
    .setNumber(++numMessages)
    .build();

notification.sound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
notificationManager.notify(1000, notification);

or

private void sendNotification(RemoteMessage.Notification notification, Map<String, String> data) {
            Bitmap icon = BitmapFactory.decodeResource(getResources(), R.drawable.logo);
    
            Intent intent = new Intent(this, MainActivity.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_ONE_SHOT);
    
            NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                   // .setContentTitle(notification.getTitle())
                    .setContentTitle(getResources().getText(R.string.app_name))
                    .setContentText(notification.getBody())
                    .setAutoCancel(true)
                    .setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))
                    .setContentIntent(pendingIntent)
                    .setStyle(new NotificationCompat.BigTextStyle().bigText(notification.getBody()))
                    .setContentInfo(notification.getTitle())
                    .setLargeIcon(icon)
                    .setColor(Color.RED)
                    .setSmallIcon(R.drawable.logo);
    
            try {
                String picture_url = data.get("picture_url");
                if (picture_url != null && !"".equals(picture_url)) {
                    URL url = new URL(picture_url);
                    Bitmap bigPicture = BitmapFactory.decodeStream(url.openConnection().getInputStream());
                    notificationBuilder.setStyle(
                            new NotificationCompat.BigPictureStyle().bigPicture(bigPicture).setSummaryText(notification.getBody())
                    );
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
    
            notificationBuilder.setDefaults(Notification.DEFAULT_VIBRATE);
            notificationBuilder.setLights(Color.YELLOW, 1000, 300);
    
            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.notify(0, notificationBuilder.build());
        }

27/07/2021 :

You should can read detail this : Expandable Notifications and Notifications Groups