密鑰監聽器沒有檢測到密鑰

Question

我對密鑰監聽器有問題，它根本沒有檢測到任何密鑰。 我可能已經搞砸了，或希望只是失去了一些簡單的東西，但我只是不能看到它。任何幫助，將不勝感激

public class OpeningMenu extends JLayeredPane implements KeyListener{ 
JFrame OpeningMenu; 
JLayeredPane layeredPane; 
JPanel backgroundPanel, arrowPanel; 

SnakeClient client; 
Login login; 
Register register; 

ImageIcon backgroundImage, arrowImage; 
JLabel backgroundLabel, arrowLabel; 

String backgroundPath = "D:/Uni/Workspace/ClientTest/loginBackground.png"; 
String arrowPath = "D:/Uni/Workspace/ClientTest/arrow.png"; 

int option = 1; 
int Xpos = 310; 
int Ypos = 332; 

public OpeningMenu(SnakeClient client) 
{ 
    this.client = client; 

    OpeningMenu = new JFrame("Opening Menu"); 
    OpeningMenu.setSize(1100,800); 
    OpeningMenu.setLayout(new BorderLayout()); 
    OpeningMenu.setLocationRelativeTo(null); // center the frame 
    OpeningMenu.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE); 

    loadImages(); 
    createUI(); 
} 

public void loadImages() 
{ 
    backgroundImage = new ImageIcon(backgroundPath); 
    arrowImage = new ImageIcon(arrowPath); 

    backgroundLabel = new JLabel(backgroundImage); 
    arrowLabel = new JLabel(arrowImage); 
} 

public void createUI() 
{ 

    layeredPane = new JLayeredPane(); 
    layeredPane.setBounds(0, 0, 1100, 800); 
    OpeningMenu.add(layeredPane); 

    backgroundPanel = new JPanel(); 
    backgroundPanel.setBounds(0,0,backgroundImage.getIconWidth() , backgroundImage.getIconHeight());  
    backgroundPanel.add(backgroundLabel); 

    arrowPanel = new JPanel(); 
    arrowPanel.setBackground(Color.BLACK); 
    arrowPanel.setBounds(Xpos, Ypos, arrowImage.getIconWidth() + 10,arrowImage.getIconHeight() + 10); 
    arrowPanel.add(arrowLabel); 

    layeredPane.add(backgroundPanel, new Integer(0),0); 
    layeredPane.add(arrowPanel, new Integer(1),0); 

    OpeningMenu.setEnabled(true); 
    OpeningMenu.setVisible(true); 
}// createUI() 

public void keyTyped(KeyEvent e) 
{ 
    System.out.println("1"); 
} 

@Override 
public void keyPressed(KeyEvent e) 
{ 
    System.out.println("2"); 

    int keyCode = e.getKeyCode(); 

    if(keyCode == KeyEvent.VK_UP) 
    { 
     System.out.println("Up-Key"); 
    } 

    if(keyCode == KeyEvent.VK_DOWN) 
    { 
     System.out.println("Down-Key"); 
    } 
} 

public void keyReleased(KeyEvent e) 
{ 
    System.out.println("3"); 
} 

Answer 1

在你KeyListener是不聽的那一刻，你必須明確地通過addKeyListener()其附加到一個組件。