[問題] 請問關於JTextField跟KeyListener

[pugboy ()]

http://ppt.cc/Fbu9

  如上圖小弟想做一個溫度轉換的小程式(攝氏轉華氏),
使用到JtextField跟KeyListener,
問題是我的KeyListener完全沒有反應...,
(我也找了資料加上了txtCelsius.requestFocus();還是不行)
不知道是缺少了什麼,
問題點我有注解起來
可以麻煩大大幫我解答嗎?
非常感謝




Code如下:
package Book;
import java.awt.event.*;
import javax.swing.*;

class CTemperature extends JFrame implements KeyListener  {
    private JTextField txtCelsius, txtFahrenheit;
    private JLabel lblCelsius, lblFahrenheit;

    CTemperature(){                  //GUI介面設定
        lblCelsius = new JLabel("攝氏溫度(C)");
        lblFahrenheit = new JLabel("華氏溫度(F)");
        txtCelsius = new JTextField("0");
        txtFahrenheit = new JTextField("0");
        lblCelsius.setBounds(10, 20, 100, 20);      add(lblCelsius);
        lblFahrenheit.setBounds(10, 40, 100, 20);   add(lblFahrenheit);
        txtCelsius.setBounds(100, 20, 100, 20);     add(txtCelsius);
        txtFahrenheit.setBounds(100, 40, 100, 20);  add(txtFahrenheit);
        txtFahrenheit.setEditable(false);

        setTitle("溫標轉換");               setLayout(null);
        setBounds(100, 100, 220, 120);     setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setFocusable(true);
        txtCelsius.requestFocus();         //對JTextField Focus?
    }
        @Override
        public void keyTyped(KeyEvent e) {  //<==按下Enter鍵將攝氏轉成華氏
            int celsius, fahrenheit;
            String a;
            if(e.getKeyCode() == KeyEvent.VK_ENTER){
                celsius = Integer.parseInt(txtCelsius.getText());
                fahrenheit = Integer.parseInt(txtFahrenheit.getText());
                fahrenheit = (celsius*9)/5+32;
                a = Integer.toString(fahrenheit);
                txtFahrenheit.setText(a);
            }
        }

        @Override
        public void keyPressed(KeyEvent e) {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void keyReleased(KeyEvent e) {
            throw new UnsupportedOperationException("Not supported yet.");
        }
    }


public class Patient {        //主程式
    public static void main(String[] args){
        CTemperature temp = new CTemperature();
    }
}

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◆ From: 140.115.223.8
推 Mije:你JTextField沒有加Listener
→ Mije:txtCelsius.addKeyListener(this);  剩下還有一些bug自己想想
→ pugboy:我加上去還是出現UnsupportedOperationException例外...
→ pugboy:感謝Mije大大 我放在KeyPressed就行了
推 Mije:你另外兩個沒用的空著就好，不用算例外