AWT » KeyAdapter類

KeyAdapter類

介紹

KeyAdapter類是一個抽象類（介面卡）用於接收鍵盤事件。這個類的所有方法都是空的。這個類是方便的類建立偵聽器物件。

類的宣告

以下是宣告的java.awt.event.KeyAdapter類：

public abstract class KeyAdapter
   extends Object
      implements KeyListener

類別建構函式

S.N. 建構函式＆說明
1 KeyAdapter() 

類方法

S.N. 方法＆說明
1 void keyPressed(KeyEvent e) 
Invoked when a key has been pressed.
2 void keyReleased(KeyEvent e) 
Invoked when a key has been released.
3 void keyTyped(KeyEvent e) 
Invoked when a key has been typed.

繼承的方法

這個類繼承的方法從以下類：

  • java.lang.Object

KeyAdapter範例

選擇使用任何編輯器建立以下java程式 D:/ > AWT > com > yiibai > gui >

AwtAdapterDemo 
package com.yiibai.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtAdapterDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AwtAdapterDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtAdapterDemo  awtAdapterDemo = new AwtAdapterDemo();        
      awtAdapterDemo.showKeyAdapterDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showKeyAdapterDemo(){
      headerLabel.setText("Listener in action: KeyAdapter");      

      final TextField textField = new TextField(10);

      textField.addKeyListener(new KeyAdapter() {
         public void keyPressed(KeyEvent e) {                
            if(e.getKeyCode() == KeyEvent.VK_ENTER){
               statusLabel.setText("Entered text: " + textField.getText());
            }
         }        
      });
      Button okButton = new Button("OK");
      okButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            statusLabel.setText("Entered text: " + textField.getText());                
         }
      });

      controlPanel.add(textField);
      controlPanel.add(okButton);    
      mainFrame.setVisible(true);  
   }
}

編譯程式，使用命令提示字元。進入到D:/> AWT，然後鍵入以下命令。

D:AWT>javac comyiibaiguiAwtAdapterDemo.java

如果沒有錯誤出現，這意味著編譯成功。使用下面的命令來執行程式。

D:AWT>java com.yiibai.gui.AwtAdapterDemo

驗證下面的輸出

AWT KeyAdapter