Question

EDIT (4/3/2017): Sorry, I was a noob back then.

I’m trying to make a turn-based battle system where the player clicks buttons on his turn. But I can’t seem to find out how to code it. Below is the code on what I did.

What should happen here is that when I click the attack button(for example) the next turn will be the monster’s turn but the playerTurn variable doesn’t change when I click the button. playerTurn is always true. Can you help me correct this? It is a turn-based battle system.

 public class BattleFrame extends JFrame implements ActionListener, Runnable {

    private JButton atkButton = new JButton("Attack");
    private JButton runButton = new JButton("Run");
    private JButton itemButton = new JButton("Item");
    private JButton magicButton = new JButton("Magic");

    private JPanel panelButtons = new JPanel();

private Random rand = new Random();
private Boolean playerTurn;
private Thread t;

public BattleFrame() {
    setSize(480, 390);
    setLayout(null);

            // I have not included the code with the setting of the JButtons
    initPanel(); // initialize the panel with buttons

    setResizable(false);
    setVisible(true);
    playerTurn = true;
    t = new Thread(this);
    t.start();
}

// I'm not so familiar with 'synchronized' but I tried it here but it doesn't change anything
public void actionPerformed(ActionEvent e) {
   Object src = e.getSource();

     if(src.equals(atkButton) && playerTurn) {
          System.out.println("Attack!");
      playerTurn = false;
 }
 else if(src.equals(runButton) && playerTurn) {
      System.out.println("Run!");
      playerTurn = false;
 }

 else if(src.equals(itemButton) && playerTurn) {
      System.out.println("Item");
      playerTurn = false;
 }

 else if(src.equals(magicButton) && playerTurn) {
      System.out.println("Magic");
      playerTurn = false;
 }

}

public void run() {
    while(true) {
       if(playerTurn == false) {
          System.out.println("Monster's turn!"); // just printing whose turn it is
           playerTurn = true;
       }
       else System.out.println("player's turn!");
   }

 }

 public static void main(String[] args) {
    new BattleFrame();

   }
}

Answer 1

A Boolean is an object, so gets compared by identity, not value.

assert new Boolean (true) == new Boolean(true);

The above will fail, as the two different Boolean objects are not the same object.

For general use, use the primitive type boolean, not the standard library class Boolean. Cases where you should use Boolean are pretty rare: it’s one of those things that exists more for symmetry than any real practical reason. If you do use it, you need to use a.equals(b) not a == b.

For more details, see:

http://www.java-samples.com/showtutorial.php?tutorialid=221