java - setContentPane 覆盖了所有内容并且 JButton 无法正常工作

Question

我正在制作一款游戏，玩家试图在迷宫中导航，但我遇到了两个绝对难倒我的错误。我的第一个问题是使用setContentPane()。每当我将其设置为我想要的背景时，它都会覆盖屏幕上的其他所有内容。我尝试过将它重新安置到我认为可能的每个地方，但它仍然掩盖了它。我的第二个问题是关于我的 JButton。每当我单击它时，它都会按预期更改播放速度，但之后我无法移动。当我在 Keylistener 中使用该方法时，它会起作用，并且它们内部具有相同的代码。我已经包含了我认为必要的所有代码，但如果您需要更多代码，请告诉我。该项目的完整源代码可以在 Here 找到。 .

package game;

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

public class Game extends JPanel implements ActionListener, KeyListener {

    private boolean upPressed    = false;
    private boolean downPressed  = false;
    private boolean rightPressed = false;
    private boolean leftPressed  = false;

    private int tileSize = 200;
    private int playerSize = tileSize / 4;
    private int playerSpeed = playerSize / 10;
    private int mazeX = 51;
    private int mazeY = 51;

    private int[][] maze = new int[mazeX][mazeY];
    private int[][] initX = new int[mazeX][mazeY];
    private int[][] initY = new int[mazeX][mazeY];
    private boolean[][] visited = new boolean[mazeX][mazeY];

    private int currentCellX = 0;
    private int currentCellY = 0;
    private int deltaX = 0;
    private int deltaY = 0;

    JComponent background = new JLabel(new ImageIcon(Main.class.getResource("/assets/ui/mainMenu.png")));
    JButton adventure = new JButton();
    JButton freePlay = new JButton();
    JButton exit = new JButton();
    JButton pause = new JButton();
    JButton resume = new JButton();

    private String screen = "menu";
    public Main main;


    public Game(Main main) {
        this.main = main;

        setFocusable(true);
        addKeyListener(this);
        addButtons();
        setUpInitialCoordinates();
        Timer timer = new Timer(1000 / 120,  this);
        timer.start();
    }


    private void tick() {
        switch (screen) {
            case "playing" :
                background.setVisible(false);
                if (upPressed) {
                    deltaY += playerSpeed;
                } else if (downPressed) {
                    deltaY -= playerSpeed;
                }
                if (rightPressed) {
                    deltaX -= playerSpeed;
                } else if (leftPressed) {
                    deltaX += playerSpeed;
                }
                break;
            case "paused":
                background.setVisible(false);
                adventure.setVisible(false);
                freePlay.setVisible(false);
                pause.setVisible(false);
                exit.setVisible(true);
                break;
            case "menu":
                main.setContentPane(new JLabel(new ImageIcon(Main.class.getResource("/assets/ui/mainMenu.png"))));
                adventure.setVisible(true);
                freePlay.setVisible(true);
                pause.setVisible(false);
                exit.setVisible(true);
                break;
        }
        repaint();
    }

    private void addButtons() {
        setLayout(null);
        add(freePlay);
        freePlay.setBounds(10, 100, 180, 80);
        freePlay.setSize(180, 80);
        freePlay.setAction(new AbstractAction() {
            @Override
            public void actionPerformed(ActionEvent ae) {
                downPressed = false;
                rightPressed = false;
                leftPressed = false;
                generateMaze();
                screen = "playing";
            }
        });
        freePlay.setIcon(new ImageIcon(Main.class.getResource("/assets/ui/buttons/freePlayUnselected.png")));
        freePlay.setRolloverIcon(new ImageIcon(Main.class.getResource("/assets/ui/buttons/freePlaySelected.png")));
    }

    private void setUpInitialCoordinates() {
    }


    private void generateMaze() {
    }


    private boolean checkForUnvisitedCells() {
    }


    private boolean checkForUnvisitedAdjacentCells() {
    }


    @Override
    public void actionPerformed(ActionEvent e) {
        tick();
    }


    @Override
    public void keyTyped(KeyEvent e) {}


    @Override
    public void keyPressed(KeyEvent e) {
    }


    @Override
    public void keyReleased(KeyEvent e) {
    }


    @Override
    public void paintComponent(Graphics g) {
    }
}

Answer 1

setContentPane 就是这样做的，它用新组件替换了以前用作内容的内容。

仔细看看How to Use Root Panes了解更多详情。

我建议更好的解决方案是使用 CardLayout，但在这种情况下，更好的解决方案是仅更改 icon 属性当前内容 Pane ...

background.setIcon(new ImageIcon(Main.class.getResource("/assets/ui/mainMenu.png")));

然后简单地将背景设置为框架的内容 Pane ...

JLabel background = new JLabel(new ImageIcon(Main.class.getResource("/assets/ui/mainMenu.png")));

//....
public Game(Main main) {
    this.main = main;
    setContentPane(background);
    //...

那就永远不要更改内容 Pane ...

然后，您可以使用 CardLayout 更改内容 Pane 上显示的内容

My second question is about my JButton. Whenever I click it, it changes to the playing speed as intended, but I can't move afterwards. It works when I use the method in my Keylistener

欢迎来到为什么不应该使用 KeyListener 的奇妙世界，按钮已经窃取了键盘焦点，并且 KeyListener 将不再响应键盘输入，因为它依赖于它注册为可聚焦和聚焦的组件。请改用键绑定(bind)。 How to Use Key Bindings