title: MainActivity.java action_settings cannot be resolved or is not a field
body: <p>This is the only error I have now in my MainActivity.java. 
  The line "if (id == R.id.action_settings)" which is created by eclipse gives the error :"action_settings cannot be resolved or is not a field"
  I appreciate your help to solve it</p>
  
  <pre><code> package chapter.two.hello_world;
  
   import android.support.v7.app.ActionBarActivity;
   import android.os.Bundle;
   import android.view.Menu;
   import android.view.MenuItem;
   import android.widget.TextView;
  
  
   public class MainActivity extends ActionBarActivity {
  
   WorldGen earth = new WorldGen("Earth", 5973, 9.78);
  
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      setStartUpWorldValues();
      }
  
   protected void setStartUpWorldValues(){
      earth.setPlanetColonies(1);
      earth.setPlanetMilitary(1);
      earth.setColonyImmigration(1000);
      earth.setBaseProtection(100);
      earth.turnForceFieldOn();
      }
  
   protected void setStartUpScreenText(){
      TextView planetNameValue = (TextView)findViewById(R.id.dataView1);
      planetNameValue.setText(earth.planetName);
      TextView planetMassValue = (TextView)findViewById(R.id.dataView2);
      planetMassValue.setText(String.valueOf(earth.planetMass));
      TextView planetGravityValue = (TextView)findViewById(R.id.dataView3);
      planetGravityValue.setText(String.valueOf(earth.planetGravity));
      TextView planetColoniesValue =  (TextView)findViewById(R.id.dataView4);
      planetColoniesValue.setText(String.valueOf(earth.planetColonies));
      TextView planetPopulationValue = (TextView)findViewById(R.id.dataView5);
      planetPopulationValue.setText(String.valueOf(earth.planetPopulation));
      TextView planetMilitaryValue = (TextView)findViewById(R.id.dataView6);
      planetMilitaryValue.setText(String.valueOf(earth.planetMilitary));
      TextView planetBaseValue = (TextView)findViewById(R.id.dataView7);
      planetBaseValue.setText(String.valueOf(earth.planetBases));
      TextView planetForceFieldValue = (TextView)findViewById(R.id.dataView8);
      planetForceFieldValue.setText(String.valueOf(earth.planetProtection));
  
  }
  
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
  }
  
  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
      // Handle action bar item clicks here. The action bar will
      // automatically handle clicks on the Home/Up button, so long
      // as you specify a parent activity in AndroidManifest.xml.
      int id = item.getItemId();
      if (id == R.id.action_settings) { // the error is here
          return true;
      }
      return super.onOptionsItemSelected(item);
    }
   }
  </code></pre>