KeyListener 不起作用并映射重叠字符

Question

我的KeyListener 和方法有效，但它们什么也没做。当我运行代码并尝试使用箭头键时，没有任何反应。我还有另一个问题。我在做游戏，我已经做了地图，但是当我把地图放进去时，地图有优先权并覆盖了我的角色。我将如何解决这些问题？ 这是JFrame 包。

package MyGamePKG;

import java.awt.BorderLayout;

public class GameJFrame extends JFrame {

private JPanel contentPane;
private int x,y,x_vel,y_vel;

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

/**
 * Create the frame.
 */
public GameJFrame() {


    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 720, 520);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    GameJPanel Jpanel = new GameJPanel();
    Jpanel.setBounds(0, 0, 720, 480);
    contentPane.add(Jpanel);
    Jpanel.setLayout(null);




}


}

这是 JPanel。

package MyGamePKG;

import java.awt.BasicStroke;

public class GameJPanel extends JPanel implements ActionListener, KeyListener {

private int frameRate = 30;
private int x=0;
private int y=0;
private int x_vel, y_vel;
private Image map;

/**
 * Create the panel.
 */
public GameJPanel() {
    new ImageIcon(getClass().getResource("/Resources/gamemap.png"));
    gamemap = map.getImage(); //error here
    this.addKeyListener(this);
    this.setFocusable(true);
    Timer timer = new Timer(30, this);      
    timer.start();


}


}

public void background()
{
    ImageIcon icon = new ImageIcon(this.getClass().getResource("/Resources/gamemap.png"));
    map = icon.getImage();
}
@Override
public void paintComponent(Graphics g)
{
    super.paintComponent(g);
    setBackground(Color.WHITE);

    Graphics2D g2d = (Graphics2D) g;

    RenderingHints rh = new RenderingHints( RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);

    g2d.setRenderingHints(rh);

    g2d.setColor(Color.green);
    g2d.setStroke(new BasicStroke(5));


    myDrawBoxOvalsandRect(x,y,100,g2d);
    myDrawArc(x+25,y+40,50,50,550,170,g2d);
} // paintComponent
public void myDrawBoxOvalsandRect( int x, int y, int scale, Graphics my_g)
{
    my_g.setColor(Color.cyan);
    my_g.fillOval(x, y, 100, 100); //face

    my_g.setColor(Color.red);
    my_g.fillOval(x+20, y+25, 15, 15); //left eye

    my_g.setColor(Color.red);
    my_g.fillOval(x+60, y+25, 15, 15); //right eye

    my_g.setColor(Color.cyan);
    my_g.fillRect(x+25,y+100,50,80);//body

    my_g.setColor(Color.cyan);
    my_g.fillRect(x-30,y+105,55,20); //left arm

    my_g.setColor(Color.cyan);
    my_g.fillRect(x+70, y+105, 60, 20); //right arm

    my_g.setColor(Color.red); 
    my_g.fillOval(x-47, y+105, 20, 20); //left hand

    my_g.setColor(Color.red);
    my_g.fillOval(x+126,y+105,20,20); //right hand

    my_g.setColor(Color.cyan); 
    my_g.fillRect(x+25, y+175, 20, 50); //left leg

    my_g.setColor(Color.cyan);
    my_g.fillRect(x+55,y+175,20,50); // right leg

}
public void myDrawArc(int x, int y, int height, int width, int angle1, int angle2, Graphics my_g)
{
    my_g.setColor(Color.red);
    my_g.drawArc(x, y, 50, 50, 550, 170); //happy face      
}
@Override
public void keyPressed(KeyEvent e) {
    // TODO Auto-generated method stub
    int c = e.getKeyCode();

    if(c == KeyEvent.VK_LEFT)
    {
        x_vel = -1;
        y_vel = 0;
    }
    if(c == KeyEvent.VK_UP)
    {
        x_vel = 0;
        y_vel = -1;
    }
    if( c == KeyEvent.VK_RIGHT)
    {
        x_vel = 1;
        y_vel = 0;
    }
    if( c == KeyEvent.VK_DOWN)
    {
        x_vel = 0;
        y_vel = 1;
    }
    repaint();

}
@Override
public void keyReleased(KeyEvent e) {
    // TODO Auto-generated method stub
    x_vel = 0;
    y_vel = 0;
    repaint();
}
@Override
public void keyTyped(KeyEvent e) {
    // TODO Auto-generated method stub

}
@Override
public void actionPerformed(ActionEvent e) {
    // TODO Auto-generated method stub
    if(x < 0)
    {
        x_vel = 0;
        x = 0;
    }
    if(x > 720)
    {
        x_vel = 0;
        x = 720;
    }
    if(y < 0)
    {
        y_vel = 0;
        y = 0;
    }
    if(y > 480)
    {
        y_vel = 0;
        y = 480;
    }
    x = x + x_vel;
    y = y + y_vel;
    repaint();

}


}

Answer 1

你有几个问题需要处理

1. 您已经创建了两组变量。一组在您的框架中，一组在您的面板中。使用 Keyalistener，您只需更改框架中的值，这不会影响面板中的值。

2. 应在事件调度线程上更新 UI。不要使用带有while(true) 和Thread.sleep() 的新线程。而是使用 javax.swing.Timer 来制作动画。在How to Use Swing Timers 上查看更多信息。你还会看到一堆例子here和here和here和here和here和here。

3. 您应该将键绑定用于键特定操作，而不是 KeyListener。在How to Use Key Bindings 上查看更多信息。也可以看一个简单的例子here

---

其他：

• 为什么在没有添加任何内容的情况下使用 ActionListener？
• 不要使用空布局。学习使用 LayoutManager，让它们为您调整大小和定位。
• 对于涂漆面板，您应该覆盖 getPreferredSize() 以设置面板的首选尺寸，并且当您 pack() 您的框架时会尊重它（您应该这样做，而不是设置尺寸）
• 不要在绘制方法中设置背景。在构造函数中执行。

---

更新

这是完整的代码。对我来说很好用

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.border.EmptyBorder;

public class GameFrame extends JFrame {

    private JPanel contentPane;

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

    /**
     * Create the frame.
     */
    public GameFrame() {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 720, 520);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        GameJPanel Jpanel = new GameJPanel();
        Jpanel.setBounds(0, 0, 720, 480);
        contentPane.add(Jpanel);
        Jpanel.setLayout(null);

    }
}

class GameJPanel extends JPanel implements ActionListener, KeyListener {

    private int frameRate = 30;
    private int x = 0;
    private int y = 0;
    private int x_vel, y_vel;
    private Image map;

    /**
     * Create the panel.
     */
    public GameJPanel() {
        map = new ImageIcon(getClass().getResource("/resources/gamemap.png")).getImage();
        this.addKeyListener(this);
        this.setFocusable(true);
        Timer timer = new Timer(30, this);
        timer.start();
        /*
        Thread myAnimationThread = new Thread() {
            @Override
            public void run() {
                while (true) {
                    repaint(); // Refresh the display which calls paintComponent
                    try {
                        Thread.sleep(1000 / frameRate);
                    } // try
                    catch (InterruptedException ex) {
                    }
                } // while
            } // run
        }; // Thread
        */
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        setBackground(Color.WHITE);

        Graphics2D g2d = (Graphics2D) g;

        RenderingHints rh = new RenderingHints(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);

        g2d.setRenderingHints(rh);

        g2d.setColor(Color.green);
        g2d.setStroke(new BasicStroke(5));


        g2d.drawImage(map, 0, 0, 720, 480, getParent());
        myDrawBoxOvalsandRect(x, y, 100, g2d);
        myDrawArc(x + 25, y + 40, 50, 50, 550, 170, g2d);
    } // paintComponent

    public void myDrawBoxOvalsandRect(int x, int y, int scale, Graphics my_g) {
        my_g.setColor(Color.cyan);
        my_g.fillOval(x, y, 100, 100); // face

        my_g.setColor(Color.red);
        my_g.fillOval(x + 20, y + 25, 15, 15); // left eye

        my_g.setColor(Color.red);
        my_g.fillOval(x + 60, y + 25, 15, 15); // right eye

        my_g.setColor(Color.cyan);
        my_g.fillRect(x + 25, y + 100, 50, 80);// body

        my_g.setColor(Color.cyan);
        my_g.fillRect(x - 30, y + 105, 55, 20); // left arm

        my_g.setColor(Color.cyan);
        my_g.fillRect(x + 70, y + 105, 60, 20); // right arm

        my_g.setColor(Color.red);
        my_g.fillOval(x - 47, y + 105, 20, 20); // left hand

        my_g.setColor(Color.red);
        my_g.fillOval(x + 126, y + 105, 20, 20); // right hand

        my_g.setColor(Color.cyan);
        my_g.fillRect(x + 25, y + 175, 20, 50); // left leg

        my_g.setColor(Color.cyan);
        my_g.fillRect(x + 55, y + 175, 20, 50); // right leg

    }

    public void myDrawArc(int x, int y, int height, int width, int angle1,
            int angle2, Graphics my_g) {
        my_g.setColor(Color.red);
        my_g.drawArc(x, y, 50, 50, 550, 170); // happy face
    }

    public void keyPressed(KeyEvent e) {
        // TODO Auto-generated method stub
        int c = e.getKeyCode();

        if (c == KeyEvent.VK_LEFT) {
            x_vel = -1;
            y_vel = 0;
        }
        if (c == KeyEvent.VK_UP) {
            x_vel = 0;
            y_vel = -1;
        }
        if (c == KeyEvent.VK_RIGHT) {
            x_vel = 1;
            y_vel = 0;
        }
        if (c == KeyEvent.VK_DOWN) {
            x_vel = 0;
            y_vel = 1;
        }
        repaint();

    }

    public void keyReleased(KeyEvent e) {
        // TODO Auto-generated method stub
        x_vel = 0;
        y_vel = 0;
        repaint();
    }

    public void keyTyped(KeyEvent e) {
        // TODO Auto-generated method stub

    }

    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        if (x < 0) {
            x_vel = 0;
            x = 0;
        }
        if (x > 720) {
            x_vel = 0;
            x = 720;
        }
        if (y < 0) {
            y_vel = 0;
            y = 0;
        }
        if (y > 480) {
            y_vel = 0;
            y = 480;
        }
        x = x + x_vel;
        y = y + y_vel;
        repaint();

    }
}