buttongrouptest.java

编程之道--java程序设计入门源代码

/**
 *　单选按钮的测试
 */
import java.awt.Toolkit;
import java.awt.Image;
import java.awt.Dimension;
import java.awt.Container;
import java.awt.Color;
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.ButtonGroup;
import javax.swing.JRadioButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class ButtonGroupTest
{
	public static void main(String[] args)
	{
		ButtonFrame frame = new ButtonFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.show();
	} 
}

/**
 *　这是定制自己的按钮框架
 */
class ButtonFrame extends JFrame
{
	private static final int WIDTH = 400;
	private static final int HEIGHT = 300;
	
	public ButtonFrame()
	{
		Container con = getContentPane();//得到了内容窗格
		
		Toolkit kit = Toolkit.getDefaultToolkit();
		Dimension screenSize = kit.getScreenSize();
		int width = screenSize.width;
		int height = screenSize.height;
		int x = (width - WIDTH)/2;
		int y = (height - HEIGHT)/2;
		setLocation(x, y);//设置坐标起点
		setSize(WIDTH, HEIGHT);//设置框架的大小
		Image image = kit.getImage("duke.gif");// duke.gif为图像文件名
		setIconImage(image);//设置框架图标
		setTitle("单选按钮的测试");//设置框架的标题
		
		JPanel centerPanel = new JPanel();
		con.add(centerPanel, BorderLayout.CENTER);
				
		ButtonPanel southPanel = new ButtonPanel(centerPanel);	
		con.add(southPanel, BorderLayout.SOUTH);//将面板添加到内容窗格中
	}
}

/**
 *　这是继承了JPanel面板类
 */
class ButtonPanel extends JPanel
{
	
	private JPanel centerPanel;
	JRadioButton yellow;
	JRadioButton blue;
	JRadioButton red;
	
	public ButtonPanel(JPanel centerPanel)
	{
		this.centerPanel = centerPanel;
		
		yellow = new JRadioButton("yellow");
		blue = new JRadioButton("blue");
		red = new JRadioButton("red");
		
		ButtonGroup group = new ButtonGroup();//生成按钮组对象
		//将按钮添加到按钮组对象中
		group.add(yellow);
		group.add(blue);
		group.add(red);		
		
		//将按钮添加到面板中
		add(yellow);
		add(blue);
		add(red);	
		
		//添加按钮事件处理
		ButtonAction action = new ButtonAction();
		yellow.addActionListener(action);
		blue.addActionListener(action);
		red.addActionListener(action);
		
		setBackground(Color.blue);//设置面板的背景颜色
	}
	
	class ButtonAction implements ActionListener
	{
		public void actionPerformed(ActionEvent event)
		{
			if(yellow.isSelected())
				centerPanel.setBackground(Color.yellow);
			else if (blue.isSelected())
				centerPanel.setBackground(Color.blue);
			else if (red.isSelected())
				centerPanel.setBackground(Color.red);			
		}
	}
}