Question

I am creating a simple Rock Paper Scissors game, but changing the traditional way it is played by adding two more choices, “Lizard” and “Spock”. The Point of this game is to make it more complex then the traditional way of playing it. Not sure if I am overloading the Action Event, but I get this weird bug in the code. there is suppose to be 5 buttons containing the Rock Paper Scissors etc., and 1 JTextArea. The problem is whenever I click the button “Spock” and the String AI gets “Spock”/choices[4] as well, It appear to be ignoring the following code below that I want it to respond to and instead goes with “You Lost… Haha” Option,

if ((e.getSource() == b5) && (AI == choices[4])) {
  text.append("It's a Tie!\n\n");
  return;
}

Also when clicking the “Lizard” Button, it also ignores the following code below and goes with the “You Won!” Option instead

if ((e.getSource() == b4) && (AI == choices[3])) {
  text.append("It's a Tie!\n\n");
  return;
}

rules to play

Scissors cut paper
Paper covers rock
Rock crushes lizard
Lizard poisons Spock
Spock smashes scissors
Scissors decapitate lizard
Lizard eats paper
Paper disproves Spock
Spock vaporizes rock
Rock crushes scissors

Complete Code for those that are Curious.
http://www.mediafire.com/?x4853rq3a4fp4ah
*No Viruses. 😉

the code:

import java.awt.event.*;
import javax.swing.*;


   class Main2 implements ActionListener
  {
    JTextArea text;
    JButton b1;
    JButton b2;
    JButton b3;
    JButton b4;
    JButton b5;
   String[] choices = { "Rock", "Paper", "Scissors", "Lizard", "Spock" };
   int l = this.choices.length;

   public static void main(String[] args)
   {
    Main2 gui = new Main2();
    gui.go();
   }
   public void go() {
    JFrame frame = new JFrame("Rock Paper Scissors");
    this.text = new JTextArea(13,40);
    JPanel panel1 = new JPanel();
    JPanel panel2 = new JPanel();
    b1 = new JButton(choices[0]);
    b2 = new JButton(choices[1]);
    b3 = new JButton(choices[2]);
    b4 = new JButton(choices[3]);
    b5 = new JButton(choices[4]);
    b1.addActionListener(this);
    b2.addActionListener(this);
    b3.addActionListener(this);
    b4.addActionListener(this);
    b5.addActionListener(this);
    text.setEditable(false);

    JScrollPane scroller = new JScrollPane(text);
    scroller.setVerticalScrollBarPolicy(22);

    panel1.add(scroller);
    panel2.add(this.b1);
    panel2.add(this.b2);
    panel2.add(this.b3);
    panel2.add(this.b4);
    panel2.add(this.b5);

    frame.getContentPane().add("Center", panel1);
    frame.getContentPane().add("South", panel2);
    frame.setSize(500, 300);
    frame.setVisible(true);
  }

  public void actionPerformed(ActionEvent e)
  {
    int nr = (int)(Math.random() *l);
    String AI = choices[nr];

    if (e.getSource() == b1) {
      text.append("Your choice was " + choices[0] + "\nComputer's choice was " + AI + "\n");
    }
    if (e.getSource() == b2) {
      text.append("Your choice was " + choices[1] + "\nComputer's choice was" + AI + "\n");
    }
    if (e.getSource() == b3) {
      text.append("Your choice was " + choices[2] + "\nComputer's choice was " + AI + "\n");
    }
    if (e.getSource() == this.b4) {
      text.append("Your choice was " + choices[3] + "\nComputer's choice was " + AI + "\n");
    }
    if (e.getSource() == this.b5) {
      text.append("Your choice was " + choices[4] + "\nComputer's choice was " + AI + "\n");
    }

    if (((e.getSource() ==b1) && (AI == choices[2])) || (AI == choices[3])) {
      text.append("You won!\n\n");
      return;
    }
    if ((e.getSource() == b1) && (AI == choices[0])) {
      text.append("It's a Tie!\n\n");
      return;
    }

    if (((e.getSource() == b1) && (AI == choices[1])) || (AI == choices[4])) {
      text.append("You Lost... Haha!\n\n");
      return;
    }

    if (((e.getSource() == b2) && (AI == choices[0])) || (AI == choices[4])) {
      text.append("You won!\n\n");
      return;
    }
    if ((e.getSource() == b2) && (AI == choices[1])) {
      text.append("It's a Tie!\n\n");
      return;
    }

    if (((e.getSource() == b2) && (AI == choices[2])) || (AI == choices[3])) {
      text.append("You Lost... Haha!\n\n");
      return;
    }

    if (((e.getSource() == b3) && (AI == choices[1])) || (AI == choices[3])) {
      text.append("You won!\n\n");
      return;
    }
    if ((e.getSource() == b3) && (AI == choices[2])) {
      text.append("It's a Tie!\n\n");
      return;
    }

    if (((e.getSource() == b3) && (AI == choices[0])) || (AI == choices[4])) {
      text.append("You Lost... Haha!\n\n");
      return;
    }

    if (((e.getSource() == b4) && (AI == choices[1])) || (AI == choices[4])) {
      text.append("You won!\n\n");
      return;
    }
    if ((e.getSource() == b4) && (AI == choices[3])) {
      text.append("It's a Tie!\n\n");
      return;
    }

    if (((e.getSource() == b4) && (AI == choices[0])) || (AI == choices[2])) {
      text.append("You Lost... Haha!\n\n");
      return;
    }

    if (((e.getSource() == b5) && (AI == choices[0])) || (AI == choices[2])) {
      text.append("You won!\n\n");
      return;
    }
    if ((e.getSource() == b5) && (AI == choices[4])) {
      text.append("It's a Tie!\n\n");
      return;
    }

    if (((e.getSource() == b5) && (AI == choices[1])) || (AI == choices[3]))    {
      text.append("You Lost... Haha!\n\n");
      return;
     }
    }
   }

Answer 1

As Hot Licks suggests, that’s your problem: you’re using == to check for String equivalence rather than use either the equals(...) or the equalsIgnoreCase(...) method. Understand that == checks if the two objects are the same which is not what you’re interested in. The methods on the other hand check if the two Strings have the same characters in the same order, and that’s what matters here. So instead of

if (fu == "bar") {
  // do something
}

do,

if (fu.equals("bar")) {
  // do something
}

or,

if (fu.equalsIgnoreCase("bar")) {
  // do something
}

---

Another issue, rather than having a chit-load of if blocks, why not use a win-matrix to simply, easily and briefly check to see if one choice beats another. Enums would be useful for this, something like this could work:

import java.util.Comparator;

public enum HandGameChoice  {
   ROCK,
   PAPER,
   SCISSORS,
   LIZARD,
   SPOCK;

   private static MyComparator myComparator = new MyComparator();

   public static int compare(HandGameChoice o1, HandGameChoice o2) {
      return myComparator.compare(o1, o2);
   }

   private static class MyComparator implements Comparator<HandGameChoice> {
      private int[][] winMatrix = {
            { 0, -1,  1,  1, -1},
            { 1,  0, -1, -1,  1},
            {-1,  1,  0,  1, -1},
            {-1,  1, -1,  0,  1},
            { 1, -1,  1, -1,  0}
      };

      @Override
      public int compare(HandGameChoice o1, HandGameChoice o2) {
         return winMatrix[o1.ordinal()][o2.ordinal()];
      }
   }
}

A class to test this enum could look like so:

public class TestHandGameChoices {
   public static void main(String[] args) {
      for (HandGameChoice choice1 : HandGameChoice.values()) {
         for (HandGameChoice choice2 : HandGameChoice.values()) {
            int value = HandGameChoice.compare(choice1, choice2);
            String result = "";
            if (value > 0) {
               result = "win";
            } else if (value < 0) {
               result = "lose";
            } else {
               result = "tie";
            }
            System.out.printf("%-8s vs %-8s: %s%n", choice1, choice2, result);
         }
      }
   }
}

The output of the test class shows:

ROCK     vs ROCK    : tie
ROCK     vs PAPER   : lose
ROCK     vs SCISSORS: win
ROCK     vs LIZARD  : win
ROCK     vs SPOCK   : lose
PAPER    vs ROCK    : win
PAPER    vs PAPER   : tie
PAPER    vs SCISSORS: lose
PAPER    vs LIZARD  : lose
PAPER    vs SPOCK   : win
SCISSORS vs ROCK    : lose
SCISSORS vs PAPER   : win
SCISSORS vs SCISSORS: tie
SCISSORS vs LIZARD  : win
SCISSORS vs SPOCK   : lose
LIZARD   vs ROCK    : lose
LIZARD   vs PAPER   : win
LIZARD   vs SCISSORS: lose
LIZARD   vs LIZARD  : tie
LIZARD   vs SPOCK   : win
SPOCK    vs ROCK    : win
SPOCK    vs PAPER   : lose
SPOCK    vs SCISSORS: win
SPOCK    vs LIZARD  : lose
SPOCK    vs SPOCK   : tie

Then the GUI would use it like so:

import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;

@SuppressWarnings("serial")
public class HandGameGui extends JPanel {
   private JTextArea tArea = new JTextArea(13, 40);

   public HandGameGui() {
      ButtonListener btnListener = new ButtonListener();
      JPanel btnPanel = new JPanel(new GridLayout(1, 0, 5, 0));
      for (HandGameChoice hgChoice : HandGameChoice.values()) {
         String choiceString = hgChoice.name();
         String initCapChoiceString = choiceString.substring(0, 1)
               + choiceString.substring(1, choiceString.length()).toLowerCase();

         JButton button = new JButton(initCapChoiceString);
         button.setActionCommand(choiceString);
         button.addActionListener(btnListener);
         btnPanel.add(button);
      }

      setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
      setLayout(new BorderLayout(5, 5));
      add(new JScrollPane(tArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
            JScrollPane.HORIZONTAL_SCROLLBAR_NEVER), BorderLayout.CENTER);
      add(btnPanel, BorderLayout.PAGE_END);
   }

   private class ButtonListener implements ActionListener {
      private Random random = new Random();
      @Override
      public void actionPerformed(ActionEvent e) {
         String actionCommand = e.getActionCommand();
         HandGameChoice userChoice = HandGameChoice.valueOf(actionCommand);
         int randomInt = random.nextInt(HandGameChoice.values().length);
         HandGameChoice aiChoice = HandGameChoice.values()[randomInt];

         int gameResult = HandGameChoice.compare(userChoice, aiChoice);
         String resultStr = "";
         if (gameResult > 0) {
            resultStr = "win";
         } else if (gameResult < 0) {
            resultStr = "lose";
         } else {
            resultStr = "tie";
         }

         String output = String.format("You chose %s, and the computer chose %s; you %s%n", 
               userChoice, aiChoice, resultStr);
         tArea.append(output);
      }
   }

   private static void createAndShowGui() {
      HandGameGui mainPanel = new HandGameGui();

      JFrame frame = new JFrame("Rock Paper Scissors Lizard Spock");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}