Android R.java error..

package com.example.happy.myapplication;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.R;
import android.R.*;
public class RegisterActivity extends AppCompatActivity {

    private ArrayAdapter adapter;
    private Spinner spinner;


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

        spinner = (Spinner) findViewById(R.id.majorSpinner);
        adapter = ArrayAdapter.createFromResource(this. R.array.major, android.R.layout.simple_spinner_dropdown_item);
        spinner .setAdapter(adapter);
    }
}