Fun Facts Keeps Crashing!

package com.example.dw.funfacts;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;

import static android.view.View.OnClickListener;

public class FunFactsActivity extends AppCompatActivity {

    public static final String TAG = FunFactsActivity.class.getSimpleName();

    private FactBook mFactBook = new FactBook();
    private ColorWheel mColorWheel = new ColorWheel();

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

        // Declare our view variables and assign them the Views from the layout file
        final TextView factLabel = (TextView) findViewById(R.id.factTextView);
        final Button showFactButton = (Button) findViewById(R.id.showFactButton);
        final RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.relativeLayout);

         OnClickListener listener = new OnClickListener() {
            @Override
            public void onClick(View v) {

                String fact = mFactBook.getFact();

                //Update the label with our dynamic fact
                factLabel.setText(fact);
                int color = mColorWheel.getColor();
                relativeLayout.setBackgroundColor(color);
                showFactButton.setText(color);
                }
            };
        showFactButton.setOnClickListener(listener);

        //Toast.makeText(this, "Yay! Our activity was created!", Toast.LENGTH_LONG).show();
        Log.d(TAG, "We're logging from the onCreate() method!");

    }

}