title: activity_main cannot be resolved or not a field
body: <p>I am a beginner in android and I was trying to make a simple application on android and this "activity_main" error is not getting cleared.I have gone through all the available answers </p>
  
  <pre><code>import android.R;
  import android.app.Activity;
  import android.os.Bundle;
  import android.view.Menu;
  public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
    }
  
    @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;
    }
  }
  </code></pre>