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多线程Java使对象在按住按钮的同时移动

1 月，1 周 Questions & Answers

按下按钮时如何使JPanel移动，松开按钮时如何停止。我试过使用线程。用Runnable和类似的方式启动（）。我总是遇到错误。有人能帮我吗


共 (3) 个答案

  1. # 1 楼答案

    像这样的事情可能会做你想做的事情：

    有一个包含

    private JPanel movingJPanel = new JPanel(); // Declare this however

public void paint(Graphics g) {
    //draw background first
    Point drawAt;
    syncronised (sync) {
        drawAt = this.drawAt
    }
    Dimension size = movingJPanel.getPreferredSize();
    Graphics paintWith = g.create(movingJPanel);
    movingJPanel.paint(paintWith);
}

private Point moveFrom = new Point(0, 0);
private Point moveTo = new Point(100, 100);    
private Point drawAt = new Point(0, 0);
private int steps = 35;
private int step = 0;
private long timeBetweenSteps = 50L;
private Object sync = new Object();
private boolean moving = false;

private Thread thread = new Thread(new Runnable() {
    public void run() {
        while (!Thread.interrupted()) {
            synchronized(sync) {
                if (moving && step < steps) {
                    step++;
                    drawAt = new Point((moveTo.x - moveFrom.x) * step / steps,
                            (moveTo.y - moveFrom.y) * step / steps)
                    drawMovingPanelIn.repaint();
                    sync.wait(timeBetweenSteps);
                }
            }
        }
    }
});

public void start() {
    synchronized(sync) {
        moving = true;
        sync.notify();
    }
}

public void start() {
    synchronized(sync) {
        moving = false;
    }
}

public void reset() {
    syncronized(sync) {
        steps = 0;
    }
}

    以及一个包含

    thread.start();

    现在，从添加到按钮的MouseListener的mousePressed和MouseReleased方法中调用start()和stop()方法

  2. # 2 楼答案

    你需要考虑一些重要的因素

    1. 按钮不是为这种方式设计的。它们被设计成在被点击（按下和释放）时触发和操作事件，所以你不能使用普通的操作API。幸运的是，还有其他方法可以确定按钮的状态。本例在ButtonModel上使用ChangeListener，并根据模型的状态采取操作
    2. 组件通常由布局管理器控制。这意味着为了能够移动组件，我们需要关闭它（也称为null或absolute布局）。通常情况下，我不鼓励这样做，但这是唯一可行的方法。然而移除布局管理器后，您将负责确保组件的位置和大小正确。。。这项工作不能掉以轻心。更多地了解你想要实现的目标会得到更好的答案
    3. 当按钮被“按下”时，我们需要一种方法来确定移动组件的方式。本例使用一个简单的enum来确定移动组件的方向。您可以同样轻松地使用x/yDelta并直接修改组件x/y位置。两者都可以
    4. Swing是一个单线程环境。也就是说，对UI的所有交互和修改都将在事件调度线程的上下文中执行。但任何阻止EDT的操作都将阻止UI开始更新或任何新事件开始处理。这意味着，为了移动组件，我们不能简单地使用while-loop，因为它永远不会结束（不会处理新事件）。相反，本例使用了一个javax.swing.Timer，它在后台等待，并在EDT上下文中的每个滴答上引发一个ActionEvent。如果出现滴答声，我们将修改面板的位置

    enter image description here

    import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.ButtonModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class MovePane {

    public static void main(String[] args) {
        new MovePane();
    }

    public MovePane() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public enum Direction {

        None, Up, Down, Left, Right;
    }

    public class TestPane extends JPanel {

        private JPanel mobby;
        private Timer moveTimer;
        private Direction moveDirection = Direction.None;

        public TestPane() {
            mobby = new JPanel();
            mobby.setBackground(Color.RED);
            mobby.setSize(50, 50);;
            setLayout(new BorderLayout());
            JPanel pool = new JPanel(null);
            pool.add(mobby);
            add(pool);
            JPanel buttons = new JPanel(new GridBagLayout());

            JButton up = new JButton("Up");
            JButton dwn = new JButton("Down");
            JButton lft = new JButton("Left");
            JButton rgt = new JButton("Right");

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.fill = GridBagConstraints.HORIZONTAL;
            gbc.gridx = 1;
            gbc.gridy = 0;
            buttons.add(up, gbc);
            gbc.gridx = 1;
            gbc.gridy = 2;
            buttons.add(dwn, gbc);
            gbc.gridx = 0;
            gbc.gridy = 1;
            buttons.add(lft, gbc);
            gbc.gridx = 2;
            gbc.gridy = 1;
            buttons.add(rgt, gbc);

            add(buttons, BorderLayout.SOUTH);

            up.getModel().addChangeListener(new ChangeHandler(Direction.Up));
            dwn.getModel().addChangeListener(new ChangeHandler(Direction.Down));
            lft.getModel().addChangeListener(new ChangeHandler(Direction.Left));
            rgt.getModel().addChangeListener(new ChangeHandler(Direction.Right));

            moveTimer = new Timer(40, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    Container parent = mobby.getParent();
                    Rectangle bounds = mobby.getBounds();
                    switch (moveDirection) {
                        case Up:
                            bounds.y ;
                            break;
                        case Down:
                            bounds.y++;
                            break;
                        case Left:
                            bounds.x ;
                            break;
                        case Right:
                            bounds.x++;
                            break;
                    }

                    if (bounds.x < 0) {
                        bounds.x = 0;
                    } else if (bounds.x + bounds.width > parent.getWidth()) {
                        bounds.x = parent.getWidth() - bounds.width;
                    }
                    if (bounds.y < 0) {
                        bounds.y = 0;
                    } else if (bounds.y + bounds.height > parent.getHeight()) {
                        bounds.y = parent.getHeight() - bounds.height;
                    }

                    mobby.setBounds(bounds);

                }
            });
            moveTimer.setInitialDelay(0);

        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(400, 400);
        }

        public class ChangeHandler implements ChangeListener {

            private Direction direction;

            public ChangeHandler(Direction direction) {
                this.direction = direction;
            }

            @Override
            public void stateChanged(ChangeEvent e) {
                ButtonModel b = (ButtonModel) e.getSource();
                if (b.isPressed()) {
                    moveDirection = direction;
                    moveTimer.start();
                } else {
                    moveTimer.stop();
                }
            }

        }
    }

}

    你可能想通读Concurrency in Swing了解更多细节

    根据OP的输入进行更新

    令人惊讶的是，使用按键代替按键也是同样的方法。你有一个开始动作和一个结束动作，你只需要弄清楚如何应用这些状态

    强烈建议您在KeyListener上使用Key Bindings。主要原因是KeyListener存在焦点问题，密钥绑定API有能力克服或控制这些问题

    基本前提是，您希望在按键和按键释放时注册按键操作。使用密钥绑定API可以相对容易地实现这一点

    注意事项：这个例子一次只允许一个方向。例如，如果您按下向上和向下，向下操作将获胜。这是因为我使用了enum作为方向。您可以通过使用xDelta和yDelta值来轻松更改此设置，这将允许您同时修改垂直和水平方向。。。但不能为你做一切；）

    import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.ButtonModel;
import javax.swing.InputMap;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class MovePane {

    public static void main(String[] args) {
        new MovePane();
    }

    public MovePane() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public enum Direction {

        None, Up, Down, Left, Right;
    }

    public class TestPane extends JPanel {

        private JPanel mobby;
        private Timer moveTimer;
        private Direction moveDirection = Direction.None;

        public TestPane() {
            mobby = new JPanel();
            mobby.setBackground(Color.RED);
            mobby.setSize(50, 50);;
            setLayout(new BorderLayout());
            JPanel pool = new JPanel(null);
            pool.add(mobby);
            add(pool);

            moveTimer = new Timer(40, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    Container parent = mobby.getParent();
                    Rectangle bounds = mobby.getBounds();
                    switch (moveDirection) {
                        case Up:
                            bounds.y ;
                            break;
                        case Down:
                            bounds.y++;
                            break;
                        case Left:
                            bounds.x ;
                            break;
                        case Right:
                            bounds.x++;
                            break;
                    }

                    if (bounds.x < 0) {
                        bounds.x = 0;
                    } else if (bounds.x + bounds.width > parent.getWidth()) {
                        bounds.x = parent.getWidth() - bounds.width;
                    }
                    if (bounds.y < 0) {
                        bounds.y = 0;
                    } else if (bounds.y + bounds.height > parent.getHeight()) {
                        bounds.y = parent.getHeight() - bounds.height;
                    }

                    mobby.setBounds(bounds);

                }
            });
            moveTimer.setInitialDelay(0);
            InputMap im = pool.getInputMap(WHEN_IN_FOCUSED_WINDOW);
            ActionMap am = pool.getActionMap();

            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, false), "UpPressed");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, true), "UpReleased");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, false), "DownPressed");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "DownReleased");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0, false), "LeftPressed");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0, true), "LeftReleased");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0, false), "RightPressed");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0, true), "RightReleased");

            KeyUpAction keyUpAction = new KeyUpAction();
            am.put("UpReleased", keyUpAction);
            am.put("DownReleased", keyUpAction);
            am.put("LeftReleased", keyUpAction);
            am.put("RightReleased", keyUpAction);

            am.put("UpPressed", new MoveAction(Direction.Up));
            am.put("DownPressed", new MoveAction(Direction.Down));
            am.put("LeftPressed", new MoveAction(Direction.Left));
            am.put("RightPressed", new MoveAction(Direction.Right));

        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(400, 400);
        }

        public class KeyUpAction extends AbstractAction {

            @Override
            public void actionPerformed(ActionEvent e) {
                moveTimer.stop();
                moveDirection = Direction.None;
            }
        }

        public class MoveAction extends AbstractAction {

            private Direction direction;

            public MoveAction(Direction direction) {
                this.direction = direction;
            }

            @Override
            public void actionPerformed(ActionEvent e) {
                moveDirection = direction;
                moveTimer.start();
            }
        }
    }
}
  3. # 3 楼答案

    使用^{}移动面板，将mouseListener添加到面板，并覆盖mousePressed和mouseReleased方法

    更新：

    评论如下：

    The OP said I want to move the panel with Keyboard buttons.

    你在问题中没有提到键盘，你只是说按钮，不管怎样，这本教程对你现在和将来都有帮助

    如果您有问题，请回来，我将发布一个移动面板的示例，但现在，我不会发布它，因为我相信您不会阅读教程，您只需复制我的示例，然后离开阅读图茨