AWT » AdjustmentListener 介面

AdjustmentListener 介面

介紹

用於接收調整事件的介面AdjustmentListener。過程調整事件，需要實現這個介面的類。

類的宣告

以下是宣告的java.awt.event.AdjustmentListener介面：

public interface AdjustmentListener
extends EventListener

介面中的方法

S.N. 方法＆說明
1 void adjustmentValueChanged(AdjustmentEvent e) 
Invoked when the value of the adjustable has changed.

繼承的方法

這個類繼承的方法從下面的介面：

  • java.awt.event.EventListener

AdjustmentListener範例

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

AwtListenerDemo.java 
package com.yiibai.gui;

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

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

   public AwtListenerDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtListenerDemo  awtListenerDemo = new AwtListenerDemo();  
      awtListenerDemo.showAdjustmentListenerDemo();
   }

   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 showAdjustmentListenerDemo(){
      headerLabel.setText("Listener in action: AdjustmentListener");      

      ScrollPane panel = new ScrollPane();      
      panel.setBackground(Color.magenta);
      panel.getHAdjustable().addAdjustmentListener(new CustomAdjustmentListener());

      Label msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);   
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");
      panel.add(msglabel);
      
      controlPanel.add(panel);
      mainFrame.setVisible(true);  
   }

   class CustomAdjustmentListener implements AdjustmentListener {
      public void adjustmentValueChanged(AdjustmentEvent e) {
         statusLabel.setText("Adjustment value: "+Integer.toString(e.getValue()));
      }
   }
}

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 comyiibaiguiAwtListenerDemo.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.AwtListenerDemo

驗證下面的輸出

AWT AdjustmentListener