He creado una aplicación que gestiona sms, he creado las notificaciones pero cuando hago clic en ellas comienza otra actividad, me gustaría saber cómo verificar si una actividad se ha detenido y reanudarla.

Aquí está el código usado para crear el intento pendiente:

private void createNotification(SmsMessage sms, Context context){

    final NotificationManager nm = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);

    String contentTitle = "";


    // construct the Notification object.
        final NotificationCompat.Builder  builder = new NotificationCompat.Builder(context)
        .setContentTitle(contentTitle)
         .setContentText(sms.getMessageBody())
         .setSmallIcon(R.drawable.ic_launcher)
         .setLargeIcon(getIconBitmap())
         .setNumber(nmessages);

        builder.setAutoCancel(true);

        //(R.drawable.stat_sample, tickerText,
          //      System.currentTimeMillis());

        // Set the info for the views that show in the notification panel.
        //notif.setLatestEventInfo(this, from, message, contentIntent);
        /*
        // On tablets, the ticker shows the sender, the first line of the message,
        // the photo of the person and the app icon.  For our sample, we just show
        // the same icon twice.  If there is no sender, just pass an array of 1 Bitmap.
        notif.tickerTitle = from;
        notif.tickerSubtitle = message;
        notif.tickerIcons = new Bitmap[2];
        notif.tickerIcons[0] = getIconBitmap();;
        notif.tickerIcons[1] = getIconBitmap();;
        */

     // Creates an explicit intent for an Activity in your app
        Intent resultIntent = new Intent(context, BasicActivity.class);

        resultIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
        // Because clicking the notification opens a new ("special") activity, there's
        // no need to create an artificial back stack.
        PendingIntent resultPendingIntent =
            PendingIntent.getActivity(
            context,
            0,
            resultIntent,
            PendingIntent.FLAG_UPDATE_CURRENT
        );


       // Ritardo in millisecondi



     builder.setContentIntent(resultPendingIntent);

     nm.notify(R.drawable.ic_drawer, builder.build());