How to reference a view in a customized notification

In the below posted code i am create a notification with a customized layout. the layout of the notification contains three action buttons.

the problem i have now is, i can not reference any of the buttons in the code so that I can navigate to another activity based on the action button clicked.what i am trying to do is when Action button 1 is clicked then Activity 1 shows up, when Action button 2 is clicked then Activity 2 shows up and so on.

Please let me know how to reference the views in customized layout of the notification?

code:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Using RemoteViews to bind custom layouts into Notification
        RemoteViews remoteViews = new RemoteViews(getPackageName(), R.layout.layout_notification);
        String notification_title = "Notification_Title";
        String notification_text = "Notification_Text";

        // Open NotificationView Class on Notification Click
        Intent intent = new Intent(this, NotificationReply.class);
        // Send data to NotificationView Class
        intent.putExtra("title", notification_title);
        intent.putExtra("text", notification_text);
        // Open NotificationView.java Activity
        PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent,PendingIntent.FLAG_UPDATE_CURRENT);

        NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
                // Set Icon
                .setSmallIcon(R.mipmap.ic_launcher)
                // Set Ticker Message
                .setTicker("Ticker")
                // Dismiss Notification
                .setAutoCancel(true)
                // Set PendingIntent into Notification
                .setContentIntent(pIntent)
                // Set RemoteViews into Notification
                .setContent(remoteViews);

        Intent intentAction1 = new Intent(this, ActAction1.class);
        PendingIntent pendingIntentActAction1 = PendingIntent.getBroadcast(this, 1,intentAction1, PendingIntent.FLAG_UPDATE_CURRENT);
        remoteViews.setOnClickPendingIntent(R.id.btn_action1, pendingIntentActAction1);

        Intent intentAction2 = new Intent(this, ActAction2.class);
        PendingIntent pendingIntentActAction2 = PendingIntent.getBroadcast(this, 2,intentAction2, PendingIntent.FLAG_UPDATE_CURRENT);
        remoteViews.setOnClickPendingIntent(R.id.btn_action2, pendingIntentActAction2);

        Intent intentAction3 = new Intent(this, ActAction3.class);
        PendingIntent pendingIntentActAction3 = PendingIntent.getBroadcast(this, 3,intentAction3, PendingIntent.FLAG_UPDATE_CURRENT);
        remoteViews.setPendingIntentTemplate(R.id.btn_action3, pendingIntentActAction3);

        // Create Notification Manager
        NotificationManager notificationmanager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

        // Build Notification with Notification Manager
        notificationmanager.notify(0, builder.build());
    }
}