Chciałbym sprawdzić, czy rekord istnieje, czy nie.

Oto, co próbowałem:

MainActivity.class

    public void onTextChanged(CharSequence s, int start, int before, int count) {

        System.out.println("Ontext changed " + new String(s.toString()));
        strDocumentFrom = s.toString();         

        if(s.toString().isEmpty()){

        } else {

             try{
                 strTransactionDate = dbHelper.getTransactionDateByDocumentNumber(strDocumentFrom);
                 //strTotalAmount = dbHelper.getTotalAmountByDocumentNumber(strDocumentFrom);
                 //strVan = dbHelper.getVanByDocumentNumber(strDocumentFrom);


                 //etTransactionDate.setText(strTransactionDate);
                 //etTotalAmount.setText(strTotalAmount);
                 //Log.d("Van", "" + strVan);
                 //etVan.setText(strVan);

             } catch (SQLiteException e) {
                 e.printStackTrace();
                 Toast.makeText(ReceivingStocksHeader.this, 
                         "Document number does not exist.", Toast.LENGTH_SHORT).show();
             }

        }

DBHelper.class

            // TODO DISPLAYING RECORDS TO TRANSRCVHEADER
        public String getTransactionDateByDocumentNumber(String strDocumentNumber){
            String[] columns = new String[]{KEY_TRANSACTIONDATE};

            Cursor c = myDataBase.query(TBL_INTRANS, 
                    columns, null, 
                    null, null, null, null, null);

            if(c != null){
                c.moveToFirst();
                String date = c.getString(0);
                return date;
            } else {
                Log.d("Error", "No record exists");
            }


            return null;
        }

Ale nie trafia do bloku catch, aby wyświetlić toast.

Co tu złego robię?