Select item on Listview and pass value to another activity

I'm a noobie in Android and I'm trying to pass a value between a item select from a listview and an activity, the listview charges data from sqlite and I even manage to add value to the listview and sqlite.

I have seen tutorials with setOnClickListener but it isn't recognized.

Here is my code:

Main class:

package com.dani.listviewsqlite;

import java.util.List;
import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.TextView;

public class TestDatabaseActivity extends ListActivity {

TextView textview1;

private CommentsDataSource datasource;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);
    datasource = new CommentsDataSource(this);
    datasource.open();

    List<Comment> values = datasource.getAllComments();

  // SimpleCursorAdapter para mostrar los items en la lista
  ArrayAdapter<Comment> adapter = new ArrayAdapter<Comment>(this,
            android.R.layout.simple_list_item_1, values);
  setListAdapter(adapter);  }
  public void onClick(View view) {
  @SuppressWarnings("unchecked")  
  ArrayAdapter<Comment> adapter = (ArrayAdapter<Comment>) getListAdapter();  
  switch (view.getId()) {
  case R.id.add:            
    String valor = null;
    AlertDialog.Builder alert = new AlertDialog.Builder(this);
    alert.setTitle("Añadir nuevo tipo");
    alert.setMessage("");
    // Coloca un edittext dentro del alert 
    final EditText input = new EditText(this);
    alert.setView(input);

    // Opcion de Confirmar
    alert.setPositiveButton("Agregar", new DialogInterface.OnClickListener() {
        @SuppressWarnings("unused")
        public void onClick(DialogInterface dialog, int whichButton) {
        @SuppressWarnings("unchecked")  
        ArrayAdapter<Comment> adapter = (ArrayAdapter<Comment>) getListAdapter();
        Comment comment = null;  
        String valor = input.getText().toString();

    //Añade el VALOR a la BD
        comment = datasource.createComment(valor);
        adapter.add(comment);
        }
    });
    // Opcion de Cancel
    alert.setNegativeButton("Cancelar", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {  
        }
    });
  alert.show();
  break;
}
adapter.notifyDataSetChanged();}
}      

Main XML

<LinearLayout
    android:id="@+id/group"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" >

    <Button
        android:id="@+id/add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Nuevo" 
        android:onClick="onClick"/>

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView" />

</LinearLayout>

<ListView
    android:id="@android:id/list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello" 
    />

</LinearLayout> 

my database class (Commentsdatasource.java):

package com.dani.listviewsqlite;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;

public class CommentsDataSource {

// Database fields
private SQLiteDatabase database;
private MySQLiteHelper dbHelper;
private String[] allColumns = { MySQLiteHelper.COLUMN_ID,
  MySQLiteHelper.COLUMN_COMMENT };

public CommentsDataSource(Context context) {
  dbHelper = new MySQLiteHelper(context);
}

public void open() throws SQLException {
  database = dbHelper.getWritableDatabase();
}

public void close() {
  dbHelper.close();
}

public Comment createComment(String comment) {
  ContentValues values = new ContentValues();
  values.put(MySQLiteHelper.COLUMN_COMMENT, comment);
  long insertId = database.insert(MySQLiteHelper.TABLE_COMMENTS, null,
    values);
  Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS,
    allColumns, MySQLiteHelper.COLUMN_ID + " = " + insertId, null,
    null, null, null);
  cursor.moveToFirst();
  Comment newComment = cursorToComment(cursor);
  cursor.close();
  return newComment;
}

public void deleteComment(Comment comment) {
  long id = comment.getId();
  System.out.println("Comment deleted with id: " + id);
  database.delete(MySQLiteHelper.TABLE_COMMENTS, MySQLiteHelper.COLUMN_ID
    + " = " + id, null);
}

public List<Comment> getAllComments() {
  List<Comment> comments = new ArrayList<Comment>();
  Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS,
    allColumns, null, null, null, null, null);

  cursor.moveToFirst();
  while (!cursor.isAfterLast()) {
    Comment comment = cursorToComment(cursor);
    comments.add(comment);
    cursor.moveToNext();
}

// make sure to close the cursor
  cursor.close();
  return comments;
}

private Comment cursorToComment(Cursor cursor) {
  Comment comment = new Comment();
  comment.setId(cursor.getLong(0));
  comment.setComment(cursor.getString(1));
  return comment;
}
} 

My comment.java class:

package com.dani.listviewsqlite;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;

 public class CommentsDataSource {

    // Database fields
  private SQLiteDatabase database;
  private MySQLiteHelper dbHelper;
  private String[] allColumns = { MySQLiteHelper.COLUMN_ID,
  MySQLiteHelper.COLUMN_COMMENT };

  public CommentsDataSource(Context context) {
    dbHelper = new MySQLiteHelper(context);
  }

  public void open() throws SQLException {
    database = dbHelper.getWritableDatabase();
  }

  public void close() {
    dbHelper.close();
  }

  public Comment createComment(String comment) {
    ContentValues values = new ContentValues();
    values.put(MySQLiteHelper.COLUMN_COMMENT, comment);
    long insertId = database.insert(MySQLiteHelper.TABLE_COMMENTS, null,
    values);
    Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS,
    allColumns, MySQLiteHelper.COLUMN_ID + " = " + insertId, null,
    null, null, null);
    cursor.moveToFirst();
    Comment newComment = cursorToComment(cursor);
    cursor.close();
    return newComment;
  }

public void deleteComment(Comment comment) {
  long id = comment.getId();
  System.out.println("Comment deleted with id: " + id);
  database.delete(MySQLiteHelper.TABLE_COMMENTS, MySQLiteHelper.COLUMN_ID
    + " = " + id, null);
}

public List<Comment> getAllComments() {
  List<Comment> comments = new ArrayList<Comment>();

  Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS,
    allColumns, null, null, null, null, null);

  cursor.moveToFirst();
  while (!cursor.isAfterLast()) {
    Comment comment = cursorToComment(cursor);
    comments.add(comment);
    cursor.moveToNext();
  }

  // make sure to close the cursor
  cursor.close();
  return comments;
}

private Comment cursorToComment(Cursor cursor) {
  Comment comment = new Comment();
  comment.setId(cursor.getLong(0));
  comment.setComment(cursor.getString(1));
  return comment;
}
} 

Thank you very much for your guidance.