JRadioButton类是一个实现一个单选按钮 - 可以选择或取消选择一个项目，其状态显示给用户。

类声明

以下是声明 javax.swing.JRadioButton类：

public class JRadioButton
   extends JToggleButton
      implements Accessible

类构造函数

创建一个未选中的单选按钮，使用指定的文本。

S.N.	构造函数 & 描述
1	JRadioButton()  Creates an initially unselected radio button with no set text.
2	JRadioButton(Action a)  Creates a radiobutton where properties are taken from the Action supplied.
3	JRadioButton(Icon icon)  Creates an initially unselected radio button with the specified image but no text.
4	JRadioButton(Icon icon, boolean selected)  Creates a radio button with the specified image and selection state, but no text.
5	JRadioButton(String text, boolean selected) Creates a radio button with the specified text and selection state.
6	JRadioButton(String text, Icon icon)  Creates a radio button that has the specified text and image, and that is initially unselected.
7	JRadioButton(String text, Icon icon, boolean selected)  Creates a radio button that has the specified text, image, and selection state.

类方法

S.N.	方法 & 描述
1	AccessibleContext getAccessibleContext()  Gets the AccessibleContext associated with this JRadioButton.
2	String getUIClassID()  Returns the name of the L&F class that renders this component.
3	protected String paramString()  Returns a string representation of this JRadioButton.
4	void updateUI()  Resets the UI property to a value from the current look and feel.

方法继承

这个类从以下类继承的方法：

• javax.swing.AbstractButton

• javax.swing.JToggleButton

• javax.swing.JComponent

• java.awt.Container

• java.awt.Component

• java.lang.Object

JRadioButton 例子

选择使用任何编辑器创建以下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.showRadioButtonDemo();
   }

   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 void showRadioButtonDemo(){
      headerLabel.setText("Control in action: RadioButton"); 

      final JRadioButton radApple = new JRadioButton("Apple", true);
      final JRadioButton radMango = new JRadioButton("Mango");
      final JRadioButton radPeer = new JRadioButton("Peer");

      radApple.setMnemonic(KeyEvent.VK_C);
      radMango.setMnemonic(KeyEvent.VK_M);
      radPeer.setMnemonic(KeyEvent.VK_P);

      radApple.addItemListener(new ItemListener() {
         public void itemStateChanged(ItemEvent e) {         
            statusLabel.setText("Apple RadioButton: " 
            + (e.getStateChange()==1?"checked":"unchecked"));
         }           
      });

      radMango.addItemListener(new ItemListener() {
         public void itemStateChanged(ItemEvent e) {             
            statusLabel.setText("Mango RadioButton: " 
            + (e.getStateChange()==1?"checked":"unchecked")); 
         }           
      });

      radPeer.addItemListener(new ItemListener() {
         public void itemStateChanged(ItemEvent e) {             
            statusLabel.setText("Peer RadioButton: " 
            + (e.getStateChange()==1?"checked":"unchecked"));
         }           
      });

      //Group the radio buttons.
      ButtonGroup group = new ButtonGroup();
      group.add(radApple);
      group.add(radMango);
      group.add(radPeer);

      controlPanel.add(radApple);
      controlPanel.add(radMango);
      controlPanel.add(radPeer);       

      mainFrame.setVisible(true);  
   }
}

编译程序，使用命令提示符。到 D:/ > SWING 然后输出以下命令。

D:SWING>javac comyiibaiguiSwingControlDemo.java

如果没有错误出现，这意味着编译成功。使用下面的命令来运行程序。

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

验证下面的输出