java - 使用箭头键

Question

我正在尝试让我的箭头键顺利移动。在大多数情况下，代码都可以工作，但是，当第一次按下箭头键时，它会跳转到 jpanel 的左上角，然后执行我想要的操作。我怎样才能让它在第一次按下箭头时停止跳跃？

感谢您的帮助。

public class myJPanel0 extends JPanel implements KeyListener
   //This panel will contain the game 
{ 
    JButton menu;
Image myImage;
Graphics g;
myJPanel1 p1;
JButton lion = new JButton(new ImageIcon("images/lion.jpg"));  
int x =100;
int y = 100;
     public myJPanel0(myJPanel1 informedp1)
     {
      super();
      setLayout(null);
      p1 = informedp1;
      setBackground(Color.MAGENTA);
      menu = new JButton("Menu");
   //   lion.setSize(49,49);
      lion.setBounds(296,355,49,80);
      menu.setBounds(new Rectangle(250,5,80,30));
      add(menu);
      add(lion);

      setFocusable(true);
  addKeyListener(this);



     }
     public void paintComponent(Graphics g) 
{
    if(p1.myImage1 == 1)
    {
    super.paintComponent(g); 
        Image myImage = Toolkit.getDefaultToolkit().getImage("images/snow.jpg");//Place      holder for now, we can come up with our own image.
    g.drawImage(myImage, 0, 0,680,460, this); 
    requestFocusInWindow();
    }else if(p1.myImage1 == 2) 
       {
           super.paintComponent(g); 
           Image myImage =    Toolkit.getDefaultToolkit().getImage("images/grass.jpg");//Place holder for now, we can come up with our own image.
           g.drawImage(myImage, 0, 0,680,460, this);  
           requestFocusInWindow();
       }
    else{
           super.paintComponent(g); 
           Image myImage = Toolkit.getDefaultToolkit().getImage("images/stone.jpg");//Place holder for now, we can come up with our own image.
           g.drawImage(myImage, 0, 0,680,460, this); 
           requestFocusInWindow();
       }
      }
      public void keyPressed(KeyEvent evt) 
  {
System.out.println("Key pressed");
int kk = evt.getKeyCode();
if(kk ==  evt.VK_LEFT) {x=x-49;} 
else if(kk ==  evt.VK_RIGHT) {x=x+49;}
else if(kk ==  evt.VK_UP) {y=y-50;}
else if(kk ==  evt.VK_DOWN) {y=y+50;}
lion.setBounds(x,y,45,75);
  }

  public void keyReleased(KeyEvent evt) {  }

   public void keyTyped(KeyEvent evt) {  }
       }

Answer 1

接下来你的问题:在开始时你设置 lion.setBounds(296,355,49,80);该对象的位置是 296,355，但是当您第一次按键时，您会使用 int x =100;
int y = 100; ，正因为如此，你才有这样的效果。将 x 和 y 更改为 int x = 296;
int y = 355;这将会起作用。