Question

I am learning how to uses databases on Android and i am trying a simple example in which i have two textboxes [brakes and rpm] when i enter values into those boxes and hit the “write button” it enters them into the database table “performance”. When i hit the “read” button it should query the table and print the contents but i get the following error while querying:

android.database.CursorIndexOutOfBoundsException: Index -1 re
quested, with a size of 0

Here is my relevant code:

private static final String KEY_ROWID = "_id";
private static final String KEY_BRAKES = "brakes";
private static final String KEY_RPM="rpm";
private static final String DATABASE_NAME = "MyDB2";
private static final String DATABASE_TABLE = "performance";
private static final int DATABASE_VERSION=1;
private static final String DATABASE_CREATE = "create table performance (_id integer primary key autoincrement, " + "brakes text not null, rpm text not null);";


    //--insert an entry to the database--
public void insertData(String filter, String data){
    ContentValues entry = new ContentValues();

    if(filter.equals("b")){
        entry.put(KEY_BRAKES, data);
        Log.d(TAG,"inserted brake data");
        db.insert(DATABASE_TABLE, null, entry);
    }
    else if (filter.equals("r")){
        entry.put(KEY_RPM, data);
        Log.d(TAG,"inserted rpm data");
        db.insert(DATABASE_TABLE, null, entry);
    }


}

    //--retrive all entries
public Cursor getAllData(){
    Log.d(TAG,"about to query");
    try{
    Cursor c = db.query(DATABASE_TABLE, new String[]{KEY_BRAKES,KEY_RPM}, null, null, null, null, null);
    Log.d(TAG,"id=" + c.getString(0));

    return c;
    }catch(Exception e){
        Log.d (TAG,"error");
        Log.e(TAG,e.toString());
    }

    return null;
}

And the way that i enter items is as follows:

brakeRead = brakes.getText().toString();
rpmRead = brakes.getText().toString();
db.open();
db.insertData("b", brakeRead);
db.insertData("r", rpmRead);
db.close();

And the way i query is as follows:

                db.open();
            Cursor c = db.getAllData();
            if(c.moveToFirst())
            {
                do{
                    output.append("id: " +  c.getString(0) + " brakes: " + c.getString(1) + " rpm: " + c.getString(2));
                }while(c.moveToNext());
            }
            db.close();

But i am getting this error while querying: android.database.CursorIndexOutOfBoundsException: Index -1 re
quested, with a size of 0

Can anyone see if i am doing something wrong?

Answer 1

Query is perfect to retieve data but you got error as listed below it means you have no record in your database, so i think there is something missing while inserting database

android.database.CursorIndexOutOfBoundsException: Index -1 re quested, with a size of 0