Question

I have Two spinner(Subject and Chapter),I crate two table(Chapter,subject).
I add all subject name in subject spinner and i need to add all chapter name on the
basis of item selection in subject spinner. My question is that how to that,because my
code is not able to do this. Please give some hint or reference.
Here is my sample code.

in onCreate()

    addItemsOnSpinner1();
    addListenerOnSpinnerItemSelection();
    addItemsOnSpinner2();
    addListenerOnSpinner2ItemSelection();

using above calling function i call appropriate method.

private void addItemsOnSpinner1() {
    try
    {
        final MySQLiteHelper m=new MySQLiteHelper(getBaseContext());
        final List<ObjectiveWiseQuestion> LocWiseProfile= m.getAllSubject();

        for (final ObjectiveWiseQuestion cn : LocWiseProfile)
        {
            list.add(cn.getSubjectName());

        }
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }

        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,list);
            dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            subSpinner.setAdapter(dataAdapter);

}

 private void addListenerOnSpinnerItemSelection()
{
    subSpinner.setOnItemSelectedListener(new mySpinnerListener());

}


private void addItemsOnChapter() 
{
    try
    {

        db=new MySQLiteHelper(getBaseContext());
        db.getWritableDatabase();
        //String name=owq.getSubjectName();
        int id=db.getSubjectId(name);
        owq.setSubjectId(id);
        long subId=owq.getSubjectId();
        final MySQLiteHelper m=new MySQLiteHelper(getBaseContext());
         final List<ObjectiveWiseQuestion> LocWiseProfile= m.getAllChapter(subId);

        for (final ObjectiveWiseQuestion cn : LocWiseProfile)
        {

            list.add(cn.getChapterName());
        }


        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,list);
            dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            chapSpinner.setAdapter(dataAdapter);
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }

}
    private void addListenerOnSpinner2ItemSelection() 
{
    try
    {
        chapSpinner.setOnItemSelectedListener(new mySpinnerListener2());
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }

}

Here is my Listener Class.

class mySpinnerListener2 implements Spinner.OnItemSelectedListener
{
    @Override
    public void onItemSelected(AdapterView parent, View v, int position,
            long id) 
    {
        Toast.makeText(parent.getContext(), "The chapter is  " +
                  parent.getItemAtPosition(position).toString(), Toast.LENGTH_LONG).show();
        owq.setChapterName(parent.getItemAtPosition(position).toString());

    }

    @Override
    public void onNothingSelected(AdapterView parent) 
    {
        // Do nothing.
    }

}
class mySpinnerListener implements Spinner.OnItemSelectedListener
{
    @Override
    public void onItemSelected(AdapterView parent, View v, int position,
            long id) 
    {
        Toast.makeText(parent.getContext(), "The subject is  " +
                  parent.getItemAtPosition(position).toString(), Toast.LENGTH_LONG).show();
        owq.setSubjectName(parent.getItemAtPosition(position).toString());
        name=parent.getItemAtPosition(position).toString();



    }

    @Override
    public void onNothingSelected(AdapterView parent) 
    {
        // Do nothing.
    }

}

When i am trying to compile it but it show null value. Give some help.
Thanks in Advance…….
Not find any good answer…..

MysqliteHelper.java

public List<ObjectiveWiseQuestion> getAllChapter(long subId)
    {
     List<ObjectiveWiseQuestion>LocwiseProfileList=new ArrayList<ObjectiveWiseQuestion>();
     String selectQuery=("select chapterName from chapter where s_id ='"+ subId +"'");
     SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst())
        {
            do {
                ObjectiveWiseQuestion owq= new ObjectiveWiseQuestion();
                owq.setChapterName(cursor.getString(2));
                LocwiseProfileList.add(owq);
              }
            while(cursor.moveToNext());
            db.close();
        }

        return LocwiseProfileList;
    }

Answer 1

Do the following change in your myspinnerlistener class.

   class mySpinnerListener implements Spinner.OnItemSelectedListener
    {
    Spinner chapSpinner;
        public mySpinnerListener(Spinner chapSpinner){
    this.chapSpinner = chapSpinner;
        }
        @Override
        public void onItemSelected(AdapterView parent, View v, int position,
                long id) 
        {
            Toast.makeText(parent.getContext(), "The subject is  " +
                      parent.getItemAtPosition(position).toString(), Toast.LENGTH_LONG).show();
            owq.setSubjectName(parent.getItemAtPosition(position).toString());
            name=parent.getItemAtPosition(position).toString();
            // fetch the chaper names and set them on spinner
    chapSpinner.setAdapter(Here pass your adapter);


        }

        @Override
        public void onNothingSelected(AdapterView parent) 
        {
            // Do nothing.
        }

    }

And this change also

 private void addListenerOnSpinnerItemSelection()
{
    subSpinner.setOnItemSelectedListener(new mySpinnerListener(chapSpinner));

}

I think this will solve your problem.