java - 在我的代码中添加一个计时器

Question

我已经搜索并尝试自己实现一个计时器，但我无法弄清楚我的生活。所以我想做的是每五秒我希望随机圆圈改变到一个新的随机位置。看起来很简单，但我无法让它工作。

public class BounceThread implements Runnable {
  JFrame frame;
  int myX = 500 / 2;
  int myY = 500 / 2;;

  int X;
  int Y;

  Canvas canvas;
  BufferStrategy bufferStrategy;
  BufferStrategy bufferStrategy2;
  boolean running = true;
  Random rand = new Random();
  Random rand2 = new Random();

  int n = rand.nextInt(450) + 1;
  int n2 = rand.nextInt(450) + 1;

  public BounceThread() {
    frame = new JFrame("Basic Game");
    JPanel panel = (JPanel) frame.getContentPane();
    panel.setPreferredSize(new Dimension(500, 500));
    panel.setLayout(null);
    canvas = new Canvas();
    canvas.setBounds(0, 0, 500, 500);
    canvas.setIgnoreRepaint(true);
    panel.add(canvas);
    canvas.addKeyListener(new KeyAdapter() {
      @Override
      public void keyPressed(KeyEvent evt) {
        moveIt(evt);
      }
    });
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setResizable(false);
    frame.setVisible(true);
    canvas.createBufferStrategy(2);
    bufferStrategy = canvas.getBufferStrategy();
    canvas.requestFocus();
  }

  public void run() {
    while (running = true) {
      Paint();
      if ((myX == n || myX == n) && (myY == n2 || myY == n2)) {

        n = rand.nextInt(450) + 1;
        n2 = rand.nextInt(450) + 1;
        n2 = 10 * (Math.round(n / 10));
        n = 10 * (Math.round(n / 10));
        Paint();

      }
    }
  }

  public static void main(String[] args) {
    BounceThread ex = new BounceThread();
    new Thread(ex).start();
  }

  public void Paint() {

    Graphics2D g = (Graphics2D) bufferStrategy.getDrawGraphics();
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
        RenderingHints.VALUE_ANTIALIAS_ON);
    g.clearRect(0, 0, 500, 500);
    Graphics2D e = (Graphics2D) bufferStrategy.getDrawGraphics();
    e.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
        RenderingHints.VALUE_ANTIALIAS_ON);
    e.clearRect(0, 0, 500, 500);

    Paint(g, e);

    bufferStrategy.show();
  }

  protected void Paint(Graphics2D g, Graphics2D e) {
    n2 = 10 * (Math.round(n / 10));
    n = 10 * (Math.round(n / 10));
    g.fillOval(myX, myY, 30, 30);

    g.setColor(Color.red);

    e.fillOval(n, n2, 30, 30);

    e.setBackground(Color.white);
  }

  public void moveIt(KeyEvent evt) {
    switch (evt.getKeyCode()) {
    case KeyEvent.VK_DOWN:
      if (myY >= 450) {
        break;
      } else {
        myY += 10;
        break;
      }
    case KeyEvent.VK_UP:
      if (myY <= 30) {
        break;
      } else {
        myY -= 10;
        break;
      }
    case KeyEvent.VK_LEFT:
      if (myX <= 30) {
        break;
      } else {
        myX -= 10;
        break;
      }
    case KeyEvent.VK_RIGHT:
      if (myX >= 450) {
        break;
      } else {
        myX += 10;
        break;
      }
    }
  }
}

Answer 1

我将从一个组件(例如 JComponent )进行扩展，并让 JFC/Swing 尽可能多地进行提升。请不要调用 canvas.setIgnoreRepaint(true); 并记住在每次移动后调用 repaint();。接下来，您需要一个用于 Timer 事件的 ActionListener。您的 switch 逻辑可以在 if-else 逻辑之外用 break 来表达。类似的东西

public class BounceThread extends JComponent implements ActionListener {
    JFrame frame;
    int myX = 500 / 2;
    int myY = 500 / 2;;

    int X;
    int Y;

    Canvas canvas;
    BufferStrategy bufferStrategy;
    boolean running = true;
    Random rand = new Random();

    int n = rand.nextInt(450) + 1;
    int n2 = rand.nextInt(450) + 1;

    public BounceThread() {
        frame = new JFrame("Basic Game");
        JPanel panel = (JPanel) frame.getContentPane();
        panel.setPreferredSize(new Dimension(500, 500));
        panel.setLayout(null);
        canvas = new Canvas();
        canvas.setBounds(0, 0, 500, 500);
        // canvas.setIgnoreRepaint(true);
        panel.add(canvas);
        canvas.addKeyListener(new KeyAdapter() {
            @Override
            public void keyPressed(KeyEvent evt) {
                moveIt(evt);
                repaint();
            }
        });
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setResizable(false);
        frame.setVisible(true);
        canvas.createBufferStrategy(2);
        bufferStrategy = canvas.getBufferStrategy();
        canvas.requestFocus();
    }

    public static void main(String[] args) {
        BounceThread ex = new BounceThread();
        int delay = 5000; // milliseconds
        new Timer(delay, ex).start();
    }

    @Override
    public void repaint() {
        Graphics2D g = (Graphics2D) bufferStrategy.getDrawGraphics();
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        Graphics2D e = (Graphics2D) bufferStrategy.getDrawGraphics();
        e.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        g.clearRect(0, 0, 500, 500);
        e.clearRect(0, 0, 500, 500);
        Paint(g, e);
        bufferStrategy.show();
        super.repaint();
    }

    protected void Paint(Graphics2D g, Graphics2D e) {
        g.fillOval(myX, myY, 30, 30);
        g.setColor(Color.red);
        e.fillOval(n, n2, 30, 30);
        e.setBackground(Color.white);
    }

    public void moveIt(KeyEvent evt) {
        switch (evt.getKeyCode()) {
        case KeyEvent.VK_DOWN:
            if (myY < 450) {
                myY += 10;
            }
            break;
        case KeyEvent.VK_UP:
            if (myY > 30) {
                myY -= 10;
            }
            break;
        case KeyEvent.VK_LEFT:
            if (myX > 30) {
                myX -= 10;
            }
            break;
        case KeyEvent.VK_RIGHT:
            if (myX < 450) {
                myX += 10;
            }
            break;
        }
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        n = rand.nextInt(450) + 1;
        n2 = rand.nextInt(450) + 1;
        repaint();
    }
}