R are not identified : <p>I creating a map project.
Main Activity =</p>

<pre><code>@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mainlayout);

    if (googleHarita == null) {
        googleHarita = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.haritafragment))
                .getMap();
</code></pre>

<p>R says "cannot resolve symbol <em>R</em>".
What can I do?</p>
