if I run the app in my phone the app stop working when I click the button should I be worry about it ??

public class FactsActivity extends ActionBarActivity {

    private FactBook mFactBook = new FactBook();
    private ColorWheel mColorWheel = new ColorWheel();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_facts);


        // declare our view variables and assign the view 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);

        View.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                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);
    }
}

public class ColorWheel{

    // Member variable (properties about the object)
         public String[] mColors = {
            "#39add1", // light blue
            "#3079ab", // dark blue
            "#c25975", // mauve
            "#e15258", // red
            "#f9845b", // orange
            "#838cc7", // lavender
            "#7d669e", // purple
            "#53bbb4", // aqua
            "#51b46d", // green
            "#e0ab18", // mustard
            "#637a91", // dark gray
            "#f092b0", // pink
            "#b7c0c7"  // light gray
    };

        // Method (abilities : things the object can do)
        public int getColor(){

        // The button was clicked, so update the fact label with a new fact
        String color = "";
        // Randomly select a fact
        Random randomGenerator = new Random(); // Construct a new Random number generator
        int randomNumber = randomGenerator.nextInt(mColors.length);

        color = mColors[randomNumber];
            int colorAsInt = Color.parseColor(color);

        return colorAsInt;
    }
}

public class FactBook {

    // Member variable (properties about the object)

    // Method (abilities : things the object can do)
         public String[] mFacts = {
                "Ants stretch when they wake up in the morning.",
                "Ostriches can run faster than horses.",
                "Olympic gold medals are actually made mostly of silver.",
                "You are born with 300 bones; by the time you are an adult you will have 206.",
                "It takes about 8 minutes for light from the Sun to reach Earth.",
                "Some bamboo plants can grow almost a meter in just one day.",
                "The state of Florida is bigger than England.",
                "Some penguins can leap 2-3 meters out of the water.",
                "On average, it takes 66 days to form a new habit.",
                "Mammoths still walked the earth when the Great Pyramid was being built." };

             public String getFact() {

        // The button was clicked, so update the fact label with a new fact
        String fact = "";
        // Randomly select a fact
        Random randomGenerator = new Random(); // Construct a new Random number generator
        int randomNumber = randomGenerator.nextInt(mFacts.length);

        fact = mFacts[randomNumber];

        return fact;
    }
}