Using Intent in an Android application to show another activity

In my Android application, I have two activity classes. I have a button on the first one and I want to show the second when it is clicked, but I get an error. Here are the classes:

public class FirstActivity extends Activity {



  @Override

  public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);



    Button orderButton = (Button)findViewById(R.id.order);



    orderButton.setOnClickListener(new View.OnClickListener() {



      @Override

      public void onClick(View view) {

        Intent intent = new Intent(FirstActivity.this, OrderScreen.class);

        startActivity(intent);

      }



    });

  }

}

The second class that should show when the button is clicked, but never does:

public class OrderScreen extends Activity {



  @Override

  public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.order);



    Button orderButton = (Button) findViewById(R.id.end);



    orderButton.setOnClickListener(new View.OnClickListener() {



      @Override

      public void onClick(View view) {

        finish();

      }



    });

  }

}

How do I create a button that will show the second activity?

Source: Tips4all