Passing empty string to db helper

Question

I'm having some real problems passing a single string from my main activity to my db helper class. Here is my main activity method which I am returning a string 'answerSetId':

 public String showNextRandomQuestion3() {


            SQLDatabaseHelper db = new SQLDatabaseHelper(this);

            //get the data from the database
            List<List<String>> listList = db.getAllAnswersByQuestion1();

            //Get the question/text/answer Strings
            List<String> questionStrings = listList.get(0); //question Strings
            List<String> answerSetIds = listList.get(4);

            //Generate random index
            Random r = new Random();
            int rand = Math.abs((r.nextInt() % questionStrings.size()));

            //get answer description for randomly selected question
            String questionString = questionStrings.get(rand); 
            String answerSetId = answerSetIds.get(rand);

            questionView.setText(questionString);

            return answerSetId;
            }

I specifically want to use this 'answerSetId' in one method in my db helper class (as part of a query). Here is my current code - but it is capturing an empty string '[]':

   public List<List<String>> getAnswers(String answerSetId) {

    List<String> array1 = new ArrayList<String>();    
    List<String> array2 = new ArrayList<String>();  

    System.out.println(answerSetId);

    SQLiteDatabase db = this.getReadableDatabase();

    String[] columns = new String[]{TDESCR, ADESCR};
    String selection = ASID+"=?";
    String[] selectionArgs = new String[]{String.valueOf(answerSetId)};
    Cursor c = db.query(TABLE_ANSWERS, columns, selection, selectionArgs, null, null, null);

   if (c.moveToFirst()) {
    do {

     String textdescr = c.getString(c.getColumnIndex(TDESCR));
     String answersdescr = c.getString(c.getColumnIndex(ADESCR));
     array1.add(textdescr);
     array2.add(answersdescr);

    } while (c.moveToNext());

 }
   List< List<String> > listArray2 = new ArrayList< List<String> >();
   listArray2.add(array1);
   listArray2.add(array2);

   return listArray2;
}

You can see that I want to use this method to retrun some more array data based on the query using the 'answerSetId' string - you'll also see where I have added a system print out which gives the empty value '[]'. But am only bothered about actually capturing the 'answerSetId' value from my main activity at this point.

How best to achieve this?

the arrays of data I will then pass onto my 'showNextAnswer()' method:

        public String showNextAnswers() {

            SQLDatabaseHelper db = new SQLDatabaseHelper(this);

            //get the data from the database
            List<List<String>> listList = db.getAnswers(answerSetId);

            //Get the question/text/answer Strings
            List<String> textDescrs = listList.get(0); //question Strings
//          List<String> answerDescrs = listList.get(1); //text strings

//          System.out.println(answerSetId);
            answerView3.setText(textDescrs.toString());

            String textDescriptions = textDescrs.toString();
//          String regex = "\\[|\\]";
//          textDescriptions = textDescriptions.replaceAll(regex, "");

            //Separate out the question/answer of text description associated with the randomly selected question
            StringTokenizer textDescr = new StringTokenizer(textDescriptions, ",");

            String first = textDescr.nextToken();
//              String second = textDescr.nextToken();
//              String third = textDescr.nextToken();
//              String fourth = textDescr.nextToken();

            subQuestionView1.setText(first);
//              subQuestionView2.setText(second);
//              subQuestionView3.setText(third);
//              answerView3.setText(fourth);
//              System.out.println(textDescr);
            return null;
            }

FYI - I call 'showNextRandomQuestion3()' from an onClick method when user clicks to go to a next question - a new random question and the related answers to that new question will appear each click:

        NextQuestionButton.setOnClickListener(new OnClickListener(){;
                @Override
        public void onClick(View v) {
                    showNextRandomQuestion3();
                    showNextAnswers();
                    countQuestions();

                }});

Answer 1

It looks like the solution is very simple. You just capture the return value of showNextRandomQuestion3(), since it returns answerSetId.

You will need to add a String parameter to the showNextAnswers() method to take the String that was returned from showNextRandomQuestion3().

So in your click event, you would do this:

 NextQuestionButton.setOnClickListener(new OnClickListener(){;
        @Override
        public void onClick(View v) {
                    String answerSetId = showNextRandomQuestion3(); //get return value
                    showNextAnswers(answerSetId); //give the ID here
                    countQuestions();

                }});

Then, just add the parameter to showNextAnswers(), and you're done!

public String showNextAnswers(String answerSetId) {

            SQLDatabaseHelper db = new SQLDatabaseHelper(this);

            //get the data from the database
            List<List<String>> listList = db.getAnswers(answerSetId); //This will work now!

            //.................