Two Cursors, ListView, CursorIndexOutOfBoundsException

As a beginner in android java world I need your help. I've got problem with famous "CursorIndexOutOfBoundsException".

I'm using SQLite db, and I have two cursors, I'm getting some rows from database. I need to get some previous values with some conditions with second cursor (c2) and put these values on ListView.

Code works with one exception: "android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0".

ListView looks OK if I just ignore this exception but I want to fix it.

I know it is connected to with Cursor. I tried开发者_StackOverflow社区 to check some conditions - it didn't help. Maybe if you could take a look at my code you find where is the cause.

Code:

public void LoadLogGrid()
{
    dbHelper=new DatabaseHelper(this);
    try
    {

    int LogName = (int) spinLog.getSelectedItemId();
    Cursor c=dbHelper.getLogByLogID(LogName);
    if (c != null) c.moveToFirst();
    int count = c.getCount();


    if (c.moveToFirst()){
        ArrayList<String> mArrayList = new ArrayList<String>();

    int i=0;
    do {

        int sVar1 = c.getInt(c.getColumnIndex("Var1")); 
        Long sId = (long) c.getInt(c.getColumnIndex("_id"));            

        Cursor c2=dbHelper.getPrevLogByLogID(LogName,sVar1);    
        c2.moveToFirst();

        if (c2!=null) {
            String sPrevOdo = c2.getString(c2.getColumnIndex("Odo"));
                mArrayList.add(sPrevOdo);
               c2.close();
        } else {
              //stopManagingCursor(c2); 
              //c2.close();
            Log.d("A:", "Something");
        }


        String [] from=new String []{"Date","Col1","Col2","Col3"};
        int [] to=new int [] {R.id.logDate,R.id.logCol1,R.id.logCol2,R.id.logCol3,R.id.rowOpt2};
        SimpleCursorAdapter sca=new LogCursorAdapter(this,R.layout.loggridrow,c,from,to,mArrayList);
        grid.setAdapter(sca);   
        registerForContextMenu(grid);
        i++;    

    } while (c.moveToNext());

        c.close();

    dbHelper.close();
    }   

    }
    catch(Exception ex)
    {
        AlertDialog.Builder b=new AlertDialog.Builder(this);
        b.setMessage(ex.toString());
        b.show();
    }

}

Query in second cursor:

public Cursor getPrevLogByLogID(long LogID, long Var1)
     {
         SQLiteDatabase db=this.getReadableDatabase();
        String[] params=new String[]{String.valueOf(LogID),String.valueOf(Var1)};

         Cursor c2=db.rawQuery("SELECT LogID as _id, Col1 from Log WHERE Col2=? AND Col3<? AND Full=1 ORDER BY Odo DESC", params);
         if (c2 != null) { c2.moveToFirst();}
         return c2;
     }  

---

Try changing your

do {
    ....
} while (c.moveToNext());

to

while (c.moveToNext()) {
    ....
}

The way it is now, it will run the loop at least once no matter what.

---

you have moved the c2 to the position as c2.moveToFirst() and after that you are doing the checking process whether it is null or not and i think the cursor should be null so that the exception is raised try putting the checking condition before moving the cursor to the first position