how does the application determine the next page based on which button is clicked? please show me the code related ?

public Story() {
    mStory = new Page[9];

    mStory[0] = new Page(
            R.drawable.page0,
            "The American Rich were an extremely wealthy class. The wealthiest out of all the rich people in the world. The top 1 percent of Americans held more wealth than the bottom 90 percent of Americans combined. Yet despite the enormous amount of wealth, they were greedy for more!",
            new Choice("Live your life working for these individuals", 1),
            new Choice("Live your life protesting against these individuals", 4)
    );

    mStory[1] = new Page(
            R.drawable.page1,
            "The one percent had made the fateful mistake that led to the downfall of Rome. They made material goods the source of personal fulfillment. In their mad quest for resources they sent spaceships to Mars to mine the planet for precious resources.",
            new Choice("Be a passive observer", 2),
            new Choice("Join the resistance movement", 5)
    );
    mStory[2] = new Page(
            R.drawable.page2,
            "They had not expected that an advanced subterranian society lived beneath the surface of Mars. The Martians having felt the greed of the 1 percent resolved to invade the planet and turn the bodies of the one percenters into fuel",
            new Choice("Be a passive observer", 3),
            new Choice("Join the Alien Army", 4)
    );
    mStory[3] = new Page(
            R.drawable.page3,
            "Before their invasion they have abducted you to tell them the 1 percent's weaknesses. You them that human beings have a general angst due to existence. They cannot wrap their heads around it.",
            new Choice("Assist in whatever manner possible", 4),
            new Choice("Go home", 6)
    );
    mStory[4] = new Page(
            R.drawable.page4,
            "You are hereby chosen by Aliens on Mars to use their spaceships to do destroy the one percent. You go to the ship and records 'Everyone will eventually die. The difference is as you lay dying you will look back on a disgusting apathetic life'",
            new Choice("Go to Earth", 6),
            new Choice("Wait for the Alien Reaction", 5)
    );
    mStory[5] = new Page(
            R.drawable.page5,
            "The aliens are startled that such a statement could possibly be novel to the one percent, but after conducting further observations concluded that you are correct. The cute ragmuffins bid you farewell with their spaceship that could transmit the statement directly to every one percenter",
            new Choice("Go to Earth", 6),
            new Choice("Destroy the one percent", 7));
    mStory[6] = new Page(
            R.drawable.page6,
            "You arrive on Earth. You have come to a deserted woodland in a spaceship capable of ending the 1 percent. Questions about life ring. Who are you to make a judgment call? Would you have been different had you been part of the 1 percent. Are the 1 percent in anyway necessary for society to functino?",
            new Choice("Kill them ALL", 7),
            new Choice("Take a ten billion dollar bribe", 8));
    mStory[7]= new Page(
            R.drawable.page6,
            "You decided that the entire top 1 percent of the population deserves extermination. Every Government on Earth is wiped out. After four generations of social upheavel everything is back to status quo. Except now the rich don't mess with Mars unless with they do it jointly with the Martian one percent! "
    );
    mStory[8]= new Page(
            R.drawable.page6,
            "So now you are one of them. You saw the opportunity and took advantage. It's not like luck had anything to do with it. So why, why would you help those outside the 1 percent. You worked to get to where you are. They're just lazy bums who don't sieze opportunities"

    );

public void setChoice1(Choice choice1) {
    mChoice1 = choice1;
}

public Choice getChoice2() {
    return mChoice2;
}

public void setChoice2(Choice choice2) {
    mChoice2 = choice2;
}