Почему KeyListener не работает?

Question

Я новичок в java и задаюсь вопросом, что не так с моим кодом.

Чтобы проверить keylistener, я нажал N, но ничего не произошло. Затем я перестроил некоторые методы, но это тоже не сработало.

Мой код ниже, любой вход приветствуется :)

import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JOptionPane; 
import javax.swing.JPanel; 
import javax.swing.JTextField; 
import javax.swing.SwingConstants; 
import javax.swing.SwingUtilities; 

import java.awt.BorderLayout; 
import java.awt.Color; 
import java.awt.Dimension; 
import java.awt.Toolkit; 
import java.awt.event.KeyEvent; 
import java.awt.event.KeyListener; 

public class Calculator extends MyFrame implements KeyListener { 

    private static final long serialVersionUID = 1L; 

    //declare variable 
    protected JPanel northPanel; 
    protected JPanel plusPanel, minusPanel, multiplyPanel, dividePanel,modPanel, equalPanel; 
    protected JPanel rowPanel1, rowPanel2, rowPanel3, rowPanel4, southPanel; 
    protected JPanel[] numPanel = new JPanel[10]; 
    protected JTextField textField; 
    protected JButton plusButton, minusButton, multiplyButton; 
    protected JButton divideButton, modButton, equalButton; 
    protected JButton[] numButton = new JButton[10]; 

    public void setTextField() { 
     textField = new JTextField("0.0"); 
     textField.setBackground(Color.GRAY); 
     textField.setHorizontalAlignment(SwingConstants.RIGHT); 
     textField.setEditable(false); 
    } 

    public void setButton() { 

     for (int i = 0; i <= 9; i++) { 
      numButton[i] = new JButton(i + ""); 
     } 

     plusButton = new JButton("+"); 
     minusButton = new JButton("-"); 
     multiplyButton = new JButton("*"); 
     divideButton = new JButton("/"); 
     modButton = new JButton("%"); 
     equalButton = new JButton("="); 

    } 


    public void setSqualJpanel() { 

     for (int i = 0; i <= 9; i++) { 
      numPanel[i] = createSquareJpanel(Color.pink, 30, numButton[i]); 
     } 
     plusPanel = createSquareJpanel(Color.green, 30, plusButton); 
     minusPanel = createSquareJpanel(Color.green, 30, minusButton); 
     multiplyPanel = createSquareJpanel(Color.green, 30, multiplyButton); 
     dividePanel = createSquareJpanel(Color.green, 30, divideButton); 
     modPanel = createSquareJpanel(Color.green, 30, modButton); 
     equalPanel = createSquareJpanel(Color.blue, 30, equalButton); 
    } 

    public void addComponents() { 
     rowPanel1 = new JPanel(); 
     rowPanel2 = new JPanel(); 
     rowPanel3 = new JPanel(); 
     rowPanel4 = new JPanel(); 
     southPanel = new JPanel (new BorderLayout()); 
     northPanel = new JPanel(new BorderLayout()); 

     northPanel.add(textField); 

     rowPanel1.add(numPanel[0]); 
     rowPanel1.add(numPanel[1]); 
     rowPanel1.add(numPanel[2]); 
     rowPanel1.add(numPanel[3]); 

     rowPanel2.add(numPanel[4]); 
     rowPanel2.add(numPanel[5]); 
     rowPanel2.add(numPanel[6]); 
     rowPanel2.add(numPanel[7]); 

     rowPanel3.add(numPanel[8]); 
     rowPanel3.add(numPanel[9]); 
     rowPanel3.add(plusPanel); 
     rowPanel3.add(minusPanel); 

     rowPanel4.add(multiplyPanel); 
     rowPanel4.add(dividePanel); 
     rowPanel4.add(modPanel); 
     rowPanel4.add(equalPanel); 

     southPanel.add(rowPanel2, BorderLayout.NORTH); 
     southPanel.add(rowPanel3, BorderLayout.CENTER); 
     southPanel.add(rowPanel4, BorderLayout.SOUTH); 

     add(northPanel, BorderLayout.NORTH); 
     add(rowPanel1, BorderLayout.CENTER); 
     add(southPanel, BorderLayout.SOUTH); 

    } 
    public void setFrameFeatures (String title) { 
     setTitle(title); 
     Dimension dim = Toolkit.getDefaultToolkit().getScreenSize(); 
     int w = getSize().width; 
     int h = getSize().height; 
     int x = (dim.width - w)/2; 
     int y = (dim.height - h)/2; 
     setLocation(x, y); 
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     setVisible(true); 

    } 

    public static void createAndShowGUI() { 
     Calculator frame = new Calculator(); 
     frame.setFrameFeatures("Simple Calculator"); 
     frame.setTextField(); 
     frame.setButton(); 
     frame.setSqualJpanel(); 
     frame.addComponents(); 
     frame.pack(); 
     frame.addListener(); 
    } 

    private void addListener() { 
      addKeyListener(this); 

    } 

    public static void main(String[] args) { 
     SwingUtilities.invokeLater(new Runnable() { 
      public void run() { 
       createAndShowGUI(); 
      } 
     }); 
    } 

    @Override 
    public void keyPressed(KeyEvent e) { 
     if(e.getKeyCode()==KeyEvent.VK_N){ 
      JOptionPane.showMessageDialog(null,"You Pressed N"); 
     } 

    } 

    @Override 
    public void keyReleased(KeyEvent e) { 
     // TODO Auto-generated method stub 

    } 

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

    } 

} 

Answer 1

Я обычно добавляю свои ключевые слушателей JPanels не кадры.