Refactoring code

I am currently creating the fact finder app and i have now refactored my code . The app is now only showing one fact and when i click on the button "show another fun fact" it only shows the word fact , i believe i am going wrong some where so can someone pleasw helo me solve this issue and also explain where i am going wrong.

Here is my code for the FunFactsActivity.java

package com.example.curtis.funfacts;

import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.Button; import android.widget.TextView; import java.util.Random;

public class FunFactsActivity extends AppCompatActivity {

private FactBook mFactBook = new FactBook();

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

    //declare are View variables and assign the views from the layout file
    final TextView factLabel = (TextView) findViewById(R.id.factTextView);
    Button showFactButton = (Button) findViewById(R.id.showFactButton);
    View.OnClickListener Listener = new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            String fact = mFactBook.getFact();
            //update the label with our dynamic fact
            factLabel.setText("fact");

            mFactBook.mFacts[0] = "Pigs are cool";
        }
    };
    showFactButton.setOnClickListener (Listener);

}

}

Here is my code for the FactBook.java

package com.example.curtis.funfacts;

import java.util.Random;

public class FactBook {

// member variable ( properties about the object )

public String[] mFacts ={ "Have a bath everyday.", "Read a book once a month.", "Always strive to be the best.", "Have a piece of fruit everyday.", "Spend time with family.", "Always exercise.", "Don't waste your time with rubbish.", "Value your time.", "Take risks.", "Don't be afraid to make mistakes.", "Don't be afraid to ask for help.", "Have morals and values."};

// method (abilities : things the object can do )
   public String getFact(){
//update fct label with new fact
       String fact = "";


   // randomly select a fact
   Random randomGenerator = new Random();//construct a new random number generator
   int randomNumber = randomGenerator.nextInt(mFacts.length);
    //convert random number to text fact
   fact = mFacts[randomNumber];

   return fact;
   }

}