R are not identified

Question

I creating a map project. Main Activity =

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

    if (googleHarita == null) {
        googleHarita = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.haritafragment))
                .getMap();

R says "cannot resolve symbol R". What can I do?

Answer 1

Go to Build option and select Clean Project option.

And then select Rebuild.