Android SQLite: Doubts in Cursor

Question

I am currently learning android SQLite database programming. While reading this tutorial from here. I came across a section of code,

getContact()
    // Getting single contact
public Contact getContact(int id) {
    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
            KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",
            new String[] { String.valueOf(id) }, null, null, null, null);
    if (cursor != null)
        cursor.moveToFirst();

    Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
            cursor.getString(1), cursor.getString(2));
    // return contact
    return contact;
}

My Questions

Question 1 If this code returns the query ,

Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
                        KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",
                        new String[] { String.valueOf(id) }, null, null, null, null);

Why do we move the cursor to the first row in this line ?

cursor.moveToFirst();

Question 2

What does this code do ?

Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
                cursor.getString(1), cursor.getString(2));

I read the official documentation but still could not understand. Can some one explain with a simple example ?

Answer 1

Question 1: Because Cursor is set before first row element initially. Question 2: It gets Strings from row which is set as current in cursor object from columns (every row consists of columns) with numbers 0, 1 and 2. Then it uses them to create contact object.