我的程序突然停止接收键盘输入

Question

This is my first question so I'll just get straight to it.

I've been developing a little 2D platformer game in Java using the Eclipse Neon IDE. I've been able to overcome any issues I've encountered so far except for the one I'm about to tell you.

As game controls usually go, I've set up the WASD keys for movement and the SPACEBAR for jumping. The character I control does respond to the key inputs so I know that this code works, but for some reason after the program has been running for about 3 minutes or so, the character stops receiving key inputs and I get this error:

java.awt.AWTEventMulticaster.keyPressed(Unknown Source)

I've tried fiddling with the code to see if I could fix it myself, but I can't figure out what's causing the problem.

Here's the relevant section of code from my Player class. You probably don't need to pay attention to any of the variables in the keyPressed() and keyReleased() methods, but just the methods themselves:

    public void keyPressed(KeyEvent keyID) { //This method checks to see which keys the user has pressed
    int key = keyID.getKeyCode();
    if (debug == false && key == KeyEvent.VK_F1) {
        debug = true;
    }
    else if (debug == true && key == KeyEvent.VK_F2) {
        debug = false;
    }

    if (death == false) {
        if (key == KeyEvent.VK_SPACE && jumping == false) {
            //Player.key = 2;
            velY = ySpeed;
            jumping = true;
            Sound.playSound("audio/playerJump.wav");
        }
        else if (key == KeyEvent.VK_D && rightIntersect == true) {
            velX = 0;
            lastKeyPressed = 'D';
            Player.key = 1;
        }
        else if (key == KeyEvent.VK_D && rightIntersect == false) {
            velX = xSpeed;
            lastKeyPressed = 'D';
            Player.key = 1;
        }
        if (key == KeyEvent.VK_A) {
            velX = -xSpeed;
            lastKeyPressed = 'A';
            Player.key = -1;
        }
    }

    else if (key == KeyEvent.VK_R && death == true) {
        for (int i = 0; i < GameFrame.getPlayerList().size(); i++) {
            Player p = GameFrame.getPlayerList().get(i);

            GameFrame.removePlayer(p);
            GameFrame.addPlayer(new Player(GameFrame.xPosStart, GameFrame.yPosStart));
            death = false;
            GameFrame.level = 1;
            GameFrame.mainTimer.setInitialDelay(0);
            GameFrame.mainTimer.start();
        }
    }
}

public void keyReleased(KeyEvent keyID) { //This method checks to see which keys the user has released
    int key = keyID.getKeyCode();

    if (key == KeyEvent.VK_A || key == KeyEvent.VK_D) {
        Player.key = 0;
        velX = 0;
    }
}

And here's the code for my KeyAdapt class that the Player class references:

public class KeyAdapt extends KeyAdapter {
Player p;

public KeyAdapt (Player player) {
    p = player;
}   
public void keyPressed (KeyEvent keyID) {
    p.keyPressed(keyID);
}
public void keyReleased (KeyEvent keyID) {
    p.keyReleased(keyID);
}

Again, this code does work. It just suddenly stops working after the program has been running for a certain amount of time. Does anyone know what might be causing this issue?

(If more information is needed, I can provide the entire code for the Player class).

Answer 1

Does anyone know what might be causing this issue?

It is not possible to say given the code you have shown us.

I suggest that you add some debugging code. For example, add something to keyPressed that logs the event received, and the state of variables such as death , jumping etcetera.

---

You say:

I get this error:

  java.awt.AWTEventMulticaster.keyPressed(Unknown Source) 

That looks like part of a line from a stacktrace, not an error message. If this is a stacktrace, you need to show us the entire trace including the exception at the beginning.

---

Finally, you should not do this:

  if (death == false) {

The correct way to write that is:

  if (!death) {

It is more concise, but more importantly it is less fragile. Imagine if you had mistyped your version as:

  if (death = false) {

One character difference. Easy to overlook. And it completely changes the meaning of the statement. It is a bad idea to use == and != to test boolean variables.

None of code that you showed us breaks because of this, but this bad habit could be used elsewhere in your code, and that might be the source of your problem.