使用主要竞标方式进行JLabel移动 [英] Make an JLabel move with Key Bidings

问题描述

我有一个简短的脚本，人们一直告诉我，我需要使用键绑定来让Jlabel移动，但我无法弄清楚如何去做。任何人都知道如何以不使用Key Listener的方式实现Key绑定，或者如果我添加一个按钮会有问题吗？

I have a short script made in swing, people keep telling me that I need to use Key bindings to get the Jlabel to move but I can't figure out how to do it. anyone have any idea on how to implement Key bindings in a way it works that does not use a Key Listener or that will be a problem if I add a button?

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.border.EmptyBorder;
import java.awt.CardLayout;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.ActionEvent;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.SwingConstants;
import java.awt.Color;
import java.awt.Font;

public class Screen extends JFrame {

    private JPanel contentPane;
    int x,y;

    /**
     * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                Screen frame = new Screen();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the frame.
 */
public Screen() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 450, 300);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(new CardLayout(0, 0));

    JPanel panel = new JPanel();
    contentPane.add(panel, "p1");
    panel.setLayout(null);

    JButton btnPlay = new JButton("Play");
    btnPlay.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            CardLayout c =(CardLayout)(contentPane.getLayout());
            c.show(contentPane, "p2");
        }
    });
    btnPlay.setBounds(185, 164, 53, 23);
    panel.add(btnPlay);

    JLabel lblGame = new JLabel("Game");
    lblGame.setHorizontalAlignment(SwingConstants.CENTER);
    lblGame.setBounds(189, 28, 46, 14);
    panel.add(lblGame);

    JPanel panel_1 = new JPanel();
    contentPane.add(panel_1, "p2");
    panel_1.setLayout(null);

    JLabel player = new JLabel("P");
    player.setHorizontalAlignment(SwingConstants.CENTER);
    player.setFont(new Font("Tahoma", Font.BOLD, 27));
    player.setForeground(Color.BLACK);
    player.setBackground(Color.BLACK);
    player.setBounds(x, y, 51, 40);
        panel_1.add(player);
}
}

推荐答案

As大多数事情，开始看一下教程，如何使用密钥绑定，几乎任何答案都只是基于这些

As with most things, start having a look at the tutorials, How to Use Key Bindings, as pretty much any answer is simply going to be based on these

你可以做一些简单的事情......

You could do something as simple as this...

import com.sun.glass.events.KeyEvent;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

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

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

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

    public interface Movable {
        public void changeLocation(int xDelta, int yDelta);
    }

    public class TestPane extends JPanel implements Movable {

        private JLabel player;

        public TestPane() {
            setLayout(null);
            player = new JLabel("X");
            player.setSize(player.getPreferredSize());
            add(player);

            setupKeyBindings();
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        protected void setupKeyBindings() {
            InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
            ActionMap am = getActionMap();

            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0), "up");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0), "down");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0), "left");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0), "right");

            int xDelta = player.getWidth();
            int yDelta = player.getHeight();

            am.put("up", new MoveAction(this, 0, -yDelta));
            am.put("down", new MoveAction(this, 0, yDelta));
            am.put("left", new MoveAction(this, -xDelta, 0));
            am.put("right", new MoveAction(this, xDelta, 0));
        }

        @Override
        public void changeLocation(int xDelta, int yDelta) {
            int xPos = player.getX() + xDelta;
            int yPos = player.getY() + yDelta;
            if (xPos + player.getWidth() > getWidth()) {
                xPos = getWidth() - player.getWidth();
            } else if (xPos < 0) {
                xPos = 0;
            }
            if (yPos + player.getHeight() > getHeight()) {
                yPos = getHeight() - player.getHeight();
            } else if (xPos < 0) {
                yPos = 0;
            }
            player.setLocation(xPos, yPos);
        }

    }

    public class MoveAction extends AbstractAction{
        private Movable movable;
        private int xDelta;
        private int yDelta;

        public MoveAction(Movable movable, int xDelta, int yDelta) {
            this.movable = movable;
            this.xDelta = xDelta;
            this.yDelta = yDelta;
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            movable.changeLocation(xDelta, yDelta);
        }

    }

}

< h1>免责声明...

我一再告诉你或你的同伴，你不应该这样使用组件。相反，您应该遵循自定义绘画路线，从长远来看，它将为您提供更大的灵活性和更少的问题。

Disclaimer...

As I have, repeatedly, told either you or your fellow class mates, you shouldn't be using components this way. Instead, you should be following a custom painting route, which will provide you with greater flexibility and far less issues in the long run.

import com.sun.glass.events.KeyEvent;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

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

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

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

    public interface Movable {

        public void changeLocation(int xDelta, int yDelta);
    }

    public class TestPane extends JPanel implements Movable {

        private Rectangle player;

        public TestPane() {
            String text = "X";
            FontMetrics fm = getFontMetrics(getFont());
            int width = fm.stringWidth(text);
            int height = fm.getHeight();

            player = new Rectangle(0, 0, width, height);

            setupKeyBindings();
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        protected void setupKeyBindings() {
            InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
            ActionMap am = getActionMap();

            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0), "up");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0), "down");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0), "left");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0), "right");

            int xDelta = player.width;
            int yDelta = player.height;

            am.put("up", new MoveAction(this, 0, -yDelta));
            am.put("down", new MoveAction(this, 0, yDelta));
            am.put("left", new MoveAction(this, -xDelta, 0));
            am.put("right", new MoveAction(this, xDelta, 0));
        }

        @Override
        public void changeLocation(int xDelta, int yDelta) {
            int xPos = player.x + xDelta;
            int yPos = player.y + yDelta;
            if (xPos + player.width > getWidth()) {
                xPos = getWidth() - player.width;
            } else if (xPos < 0) {
                xPos = 0;
            }
            if (yPos + player.height > getHeight()) {
                yPos = getHeight() - player.height;
            } else if (xPos < 0) {
                yPos = 0;
            }
            player.setLocation(xPos, yPos);
            repaint();
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            g2d.setColor(Color.RED);
            g2d.draw(player);
            FontMetrics fm = g2d.getFontMetrics();
            g2d.drawString("X", player.x, player.y + fm.getAscent());
            g2d.dispose();
        }

    }

    public class MoveAction extends AbstractAction {

        private Movable movable;
        private int xDelta;
        private int yDelta;

        public MoveAction(Movable movable, int xDelta, int yDelta) {
            this.movable = movable;
            this.xDelta = xDelta;
            this.yDelta = yDelta;
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            movable.changeLocation(xDelta, yDelta);
        }

    }

}

您还应该使用适当的布局管理器。这些可以保护你很多头发和时间。

You should also be making appropriate use layout managers. These will safe you a lot of hair and time.

参见在容器中布置组件以获取更多详细信息

See Laying Out Components Within a Container for more details

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