JButton類是一個實現按鈕。這個組件有一個標簽，按下時產生一個事件。它也可以有圖片。

類聲明

以下是聲明的 javax.swing.JButton類：

public class JButton
   extends AbstractButton
      implements Accessible

類構造函數

S.N.	構造函數 & 描述
1	JButton()  Creates a button with no set text or icon.
2	JButton(Action a)  Creates a button where properties are taken from the Action supplied.
3	JButton(Icon icon)  Creates a button with an icon.
4	JButton(String text)  Creates a button with text.
5	JButton(String text, Icon icon)  Creates a button with initial text and an icon.

類方法

S.N.	方法 & 描述
1	AccessibleContext getAccessibleContext()  Gets the AccessibleContext associated with this JButton.
2	String getUIClassID()  Returns a string that specifies the name of the L&F class that renders this component.
3	boolean isDefaultButton()  Gets the value of the defaultButton property, which if true means that this button is the current default button for its JRootPane.
4	boolean isDefaultCapable()  Gets the value of the defaultCapable property.
5	protected String paramString()  Returns a string representation of this JButton.
6	void removeNotify()  Overrides JComponent.removeNotify to check if this button is currently set as the default button on the RootPane, and if so, sets the RootPane's default button to null to ensure the RootPane doesn't hold onto an invalid button reference.
7	void setDefaultCapable(boolean defaultCapable)  Sets the defaultCapable property, which determines whether this button can be made the default button for its root pane.
8	void updateUI()  Resets the UI property to a value from the current look and feel.

方法繼承

這個類從以下類繼承的方法：

• javax.swing.AbstractButton

• javax.swing.JComponent

• java.awt.Container

• java.awt.Component

• java.lang.Object

JButton 例子

選擇使用任何編輯器創建以下java程序在 D:/ > SWING > com > yiibai > gui >

SwingControlDemo.java

package com.yiibai.gui;
 
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class SwingControlDemo {
    
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;

   public SwingControlDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      SwingControlDemo  swingControlDemo = new SwingControlDemo();      
      swingControlDemo.showButtonDemo();
   }

   private void prepareGUI(){
      mainFrame = new JFrame("Java Swing 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 JLabel("", JLabel.CENTER);        
      statusLabel = new JLabel("",JLabel.CENTER);    

      statusLabel.setSize(350,100);

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

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
    
   private static ImageIcon createImageIcon(String path, 
      String description) {
      java.net.URL imgURL = SwingControlDemo.class.getResource(path);
      if (imgURL != null) {
         return new ImageIcon(imgURL, description);
      } else {            
         System.err.println("Couldn't find file: " + path);
         return null;
      }
   }   

   private void showButtonDemo(){

      headerLabel.setText("Control in action: Button"); 

      //resources folder should be inside SWING folder.
      ImageIcon icon = createImageIcon("/resources/java_icon.png","Java");

      JButton okButton = new JButton("OK");        
      JButton javaButton = new JButton("Submit", icon);
      JButton cancelButton = new JButton("Cancel", icon);
      cancelButton.setHorizontalTextPosition(SwingConstants.LEFT);   

      okButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            statusLabel.setText("Ok Button clicked.");
         }          
      });

      javaButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            statusLabel.setText("Submit Button clicked.");
         }
      });

      cancelButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            statusLabel.setText("Cancel Button clicked.");
         }
      });

      controlPanel.add(okButton);
      controlPanel.add(javaButton);
      controlPanel.add(cancelButton);       

      mainFrame.setVisible(true);  
   }
}

編譯程序，使用命令提示符。到 D:/ > SWING 然後鍵入以下命令。

D:SWING>javac comyiibaiguiSwingControlDemo.java

如果冇有錯誤出現，這意味著編譯成功。使用下麵的命令來運行程序。

D:SWING>java com.yiibai.gui.SwingControlDemo

驗證下麵的輸出