java - 我如何创建一个使用 swing 进行计数的计时器

Question

我想创建一个可以计时的计时器。由于我的游戏使用 swing 组件，我也想使用 swing 组件来完成此任务。

我还希望将计时器重新绘制到 JLabel 上。当玩家与终点 JLabel 碰撞时，它应该停止计时器

当我尝试在 JLabel 上打印计时器时，出现以下问题:javax.swing.Timer@42cc41de

这个类是gamepane类。它是创建游戏所有组件的地方。墙壁是在这里 build 的。冲突是使用索引的 for 循环。墙壁呈阵列状。这是我的游戏的精简版，仅包含 6 面墙。我通常有 49 个。我还减少了一些不必要的类，例如用于文件的类和其中有我的第二个迷宫的类。

import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.time.Duration;
import java.time.Instant;

/**
 * demonstrates basic animation using a timer, an action listener, and a key
 * listener demonstrates basic collisions between rectangular objects
 * 
 * @author 602052004
 */

public class GamePane extends JPanel implements ActionListener, KeyListener {// *change
                                                                                // GamePane
                                                                                // to
                                                                                // GamePane
    // This is were the game screen is made and the player is created.

    static final long serialVersionUID = 1L;

    private Duration timeOutDuration = Duration.ofSeconds(5);
    private Instant startTime; // Set this when you're ready to start the timer


    JLabel player = new JLabel();
    JLabel finish = new JLabel();
    JLabel instructions = new JLabel(
            "The controls for this game will be using the WASD keys. W is going up, A is going to the left, S is going down and, D is going right.");
    JFrame gameFrame;
    int playerSpeed = 4;
    int FPS = 40;

    // This array holds my Jlabels for the walls.I used it so that i can have a
    // for loop with an index for the labels.
    JLabel[] walls = new JLabel[6];//this is cut down from 49-6
    {

        walls[0] = new JLabel();
        walls[1] = new JLabel();
        walls[2] = new JLabel();
        walls[3] = new JLabel();
        walls[4] = new JLabel();
        walls[5] = new JLabel();

    }
    private final Set<Integer> keys = new HashSet<>();

    // The keys set holds the keys being pressed

    public static void main(String[] args) {
        // Open the GUI window
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                // Create a new object and
                // run its go() method
                new GamePane().go();
            }
        });
    }

    GamePane() {
        // Run the parent class constructor
        super();
        // Allow the panel to get focus
        setFocusable(true);
        // Don't let keys change the focus

    }

    protected void go() {
        setLayout(new CardLayout());
        // Setup the window
        gameFrame = new JFrame();
        // Add this panel to the window
        gameFrame.setLayout(new CardLayout());
        gameFrame.add(this, "main");
        gameFrame.setContentPane(this);

        // Set's the window properties
        gameFrame.setTitle("main");
        gameFrame.setSize(800, 600);
        gameFrame.setLocationRelativeTo(null);
        gameFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        gameFrame.setVisible(true);
        gameFrame.add(new ButtonPane(gameFrame), "buttons");
        // Creates the new JPanel that will hold the game.
        JPanel gamestage = new JPanel();
        gamestage.setBackground(Color.darkGray);
        gameFrame.add(gamestage, "game");
        gamestage.setLayout(null);
        // *Move the setup of the player and the timer under the walls
        // Get a sample of collisions going so that i can do it over the weekend
        // Setup the movable box
        player.setBounds(25, 25, 20, 20);
        player.setVisible(true);
        player.setBackground(Color.red);
        // Opaque makes the background visible
        player.setOpaque(true);

        // Setup the key listener
        addKeyListener(this);
        // Null layout allows moving objects!!!
        gamestage.add(player);
        // Set the timer
        Timer tm = new Timer(1000 / FPS, this);
        tm.start();
        Timer gameTimer = new Timer(1000 / 30, this);
        gameTimer.start();
        System.out.println(gameTimer);
        walls[0].setBounds(10, 15, 10, 480);// left height
        walls[0].setVisible(true);
        walls[0].setBackground(Color.white);
        walls[0].setOpaque(true);
        gamestage.add(walls[0]);

        walls[1].setBounds(10, 10, 490, 10);// top width
        walls[1].setVisible(true);
        walls[1].setBackground(Color.white);
        walls[1].setOpaque(true);
        gamestage.add(walls[1]);

        walls[39].setBounds(490, 10, 10, 480);// Right width
        walls[39].setVisible(true);
        walls[39].setBackground(Color.white);
        walls[39].setOpaque(true);
        gamestage.add(walls[39]);

        // wall3.setBounds(x, y, width, height);
        walls[2].setBounds(10, 100, 100, 10);
        walls[2].setVisible(true);
        walls[2].setBackground(Color.white);
        walls[2].setOpaque(true);
        gamestage.add(walls[2]);

        walls[3].setBounds(100, 60, 10, 40);
        walls[3].setVisible(true);
        walls[3].setBackground(Color.white);
        walls[3].setOpaque(true);
        gamestage.add(walls[3]);

        walls[4].setBounds(70, 60, 35, 10);
        walls[4].setVisible(true);
        walls[4].setBackground(Color.white);
        walls[4].setOpaque(true);
        gamestage.add(walls[4]);


        finish.setBounds(30, 455, 20, 20); // *make the game change to the main
                                            // screen when finished
                                            // Add a timer
        finish.setVisible(true);
        finish.setBackground(Color.LIGHT_GRAY);
        finish.setOpaque(true);
        gamestage.add(finish);

        instructions.setVisible(true);
        instructions.setOpaque(true);
        instructions.setBounds(510, 10, 265, 525);
        instructions.setBackground(Color.GRAY);
        instructions.setForeground(Color.white);
        gamestage.add(instructions);

    }

    /**
     * Check if two JLabel objects are touching &
     * 
     * @param a
     *            The first JLabel
     * @param b
     *            The second JLabel
     * @return true if the JLabels are touching
     */
    public boolean areColliding(JLabel a, JLabel b) {
        return a.getBounds().intersects(b.getBounds());
    }

    /**
     * this method makes the player move. It takes the players speed and subtracts
     * or adds the player speed to the current position of the player. It also
     * figures out were the player is at currently as well. This method also
     * contains a for loop which is used to see if the player is colliding with the
     * walls
     * 
     * @param arg0
     */
    @Override
    public void actionPerformed(ActionEvent arg0) {
        // Move up if W is pressed
        if (keys.contains(KeyEvent.VK_W)) {
            player.setLocation(player.getX(), player.getY() - playerSpeed);
        }
        // Move right if D is pressed
        if (keys.contains(KeyEvent.VK_D)) {
            player.setLocation(player.getX() + playerSpeed, player.getY());
        }
        // Move down if S is pressed
        if (keys.contains(KeyEvent.VK_S)) {
            player.setLocation(player.getX(), player.getY() + playerSpeed);
        }
        // Move left if A is pressed
        if (keys.contains(KeyEvent.VK_A)) {
            player.setLocation(player.getX() - playerSpeed, player.getY());
        }

        for (int i = 0; i < walls.length; i++) {
            if (areColliding(walls[i], player)) { // Reposition the target
                int newX = (int) (25);// This is the new location of the player in the X axis once it hits a wall
                int newY = (int) (25);// this is the new location of the player in the Y axis once it hits a wall
                player.setLocation(newX, newY);// Sets the location of the player once the new X and Y location is set

            }
        }

        if (areColliding(finish, player)) {// to change the pane when you fimish the game
            // Reposition the target
            int newX = 25;
            int newY = 25;
            player.setLocation(newX, newY);
            CardLayout layout = (CardLayout) gameFrame.getContentPane().getLayout();
            layout.show(gameFrame.getContentPane(), "buttons");
        }

        if (startTime != null) {
            Duration runningTime = Duration.between(startTime, Instant.now());
            Duration timeRemainig = timeOutDuration.minus(runningTime);
            if (timeRemainig.isNegative() || timeRemainig.isZero()) {
                // Time has run out...
                 startTime = null; // stop the timer
                 System.out.println("finish");
            } else {
                // Update the UI
                repaint();
            }
        }
    }

    @Override
    public void keyPressed(KeyEvent e) {
        // Add the key to the list
        // of pressed keys
        if (!keys.contains(e.getKeyCode())) {
            keys.add(e.getKeyCode());
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {
        // Remove the key from the
        // list of pressed keys
        keys.remove((Integer) e.getKeyCode());
    }

    @Override
    public void keyTyped(KeyEvent e) {
    }


}

这是包含按钮和操作监听器的按钮 Pane 。它还为我改变了屏幕。

/**
 * This pane contains the button and sets up the button pane
 */
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class ButtonPane extends JPanel {

    private JButton startBTN;// Calls the JButton
    JFrame game;

    public ButtonPane(JFrame g) {
        game = g;
        setLayout(new GridBagLayout());
        setBackground(Color.gray);// Sets the menu stages color blue
        startBTN = new JButton("Start");// Creates a new button
        add(startBTN);// Adds the button on the startStage



        startBTN.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (game.getContentPane().getLayout() instanceof CardLayout) {
                    CardLayout layout = (CardLayout) getParent().getLayout();
                    layout.show(game.getContentPane(), "game");

                }
            }
        });
    }

}

Answer 1

when I try to print out the timer on a JLabel I get this issue: javax.swing.Timer@42cc41de

Timer 不携带任何“时间”信息，它只是负责在事件调度线程上定期调度回调。

为了打印运行时间或剩余时间，您需要根据需要设置Duration 的格式。

因此，在这个 block 中，您需要使用一些信息实际更新标签，调用repaint将简单地按原样绘制状态。

if (startTime != null) {
    Duration runningTime = Duration.between(startTime, Instant.now());
    Duration timeRemainig = timeOutDuration.minus(runningTime);
    if (timeRemainig.isNegative() || timeRemainig.isZero()) {
        // Time has run out...
         startTime = null; // stop the timer
         System.out.println("finish");
    } else {
        // Update the UI
        //repaint();
        // Format the duration and update the label...
    }
}

如 How could I add a refreshing timer to a JLabel using swing components 中所述，您可以使用以下内容生成 Duration 的 String:

long hours = timeRemainig.toHours();
long mins = timeRemainig.minusHours(hours).toMinutes();

// Or if you're lucky enough to be using Java 9+
//String formatted = String.format("%dhrs %02dmins", duration.toHours(), duration.toMinutesPart());
String formatted = String.format("%dhrs %02dmins", hours, mins);

然后相应地设置标签的文本

// Sorry can't identify your count down label...
countDownLabel.setText(formatted);

此外，您真的真的只需要一个定时器