Java-在CardLayout中切换面板时游戏线程冻结

Question

I'm working on a 2D game in Java, using no libraries.

In my games InputHandler (used for movement, quitting, etc,.), when I press "Escape," the button to switch to the pause menu, and then hit the "Back" button, my player can no longer move.

PausePanelGUI:

public class PausePanelGUI extends JPanel {

public PausePanelGUI(LayoutManager layout, Game game) {
    super(layout);

    JButton backBtn = new JButton("Back");
    backBtn.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            try {
                CardLayout c = new CardLayout();
                c = (CardLayout)(GameLauncher.getMainLauncherPanel().getLayout());
                c.show(GameLauncher.getMainLauncherPanel(), "Game");
                game.resume();
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    });
    backBtn.setBounds(250, 200, 150, 25);

    this.add(backBtn);
}}

Escape button in InputHandler:

if (ke.getKeyCode() == KeyEvent.VK_ESCAPE) {
        try {
            CardLayout c = new CardLayout();
            c = (CardLayout)(GameLauncher.getMainLauncherPanel().getLayout());
            c.show(GameLauncher.getMainLauncherPanel(), "Pause");
            game.pause();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

Pause and Resume methods:

public synchronized void resume() {
    System.out.println("Game resumed!");
    this.isPaused = false;
}

public synchronized void pause() {
    System.out.println("Game paused!");
    this.isPaused = true;
}

Run method:

while (isRunning) {
        if (!this.isPaused) {
            long now = System.nanoTime();
            delta += (now - lastTime) / nsPerTick;
            lastTime = now;
            boolean shouldRender = true;

            while (delta >= 1) {
                ticks++;
                update();
                delta -= 1;
                shouldRender = true;
            }

            try {
                Thread.sleep(2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            if (shouldRender) {
                frames++;
                repaint();
            }

            if (System.currentTimeMillis() - lastTimer >= 1000) {
                lastTimer += 1000;
                frames = 0;
                ticks = 0;
            }
        }
    }

Any help? :3

Answer 1

I fixed it simply by adding requestFocus();. The thread wasn't actually freezing, my InputHandler just wasn't being registered.