Have occured error in the following given code in the below website
<p><a href="https://developers.facebook.com/docs/mobile/android/build/" rel="nofollow">https://developers.facebook.com/docs/mobile/android/build/</a></p>

<p>Have occurred error in the following given code in the below website </p>

<pre><code>   package com.greatapp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
 import com.facebook.android.*;
 import com.facebook.android.Facebook.*;

  public class MyGreatActivity extends Activity {

   Facebook facebook = new Facebook("YOUR_APP_ID");

   @Override
   public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
   &lt;i&gt; setContentView(R.layout.main);  &lt; i&gt;  I have gotten error here

    facebook.authorize(this, new DialogListener() {
        @Override
        public void onComplete(Bundle values) {}

        @Override
        public void onFacebookError(FacebookError error) {}

        @Override
        public void onError(DialogError e) {}

        @Override
        public void onCancel() {}
      });
   }

  @Override
   public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    facebook.authorizeCallback(requestCode, resultCode, data);
   }
  }
</code></pre>

<p><code>setContentView(R.layout.main);</code>
The error tells us to create a field <code>main</code> in type <code>layout</code>. I tried it but <code>R.java</code> file cannot be modified manually. 
How can I solve this error?</p>
