我的源程序如下：importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassfirstextendsJFrameimplementsActionListener{Containerc;JButtonle=newJButton("左齐");...

我的源程序如下：

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class first extends JFrame implements ActionListener

{

Container c;

JButton le=new JButton("左齐");

JButton mi=new JButton("居中");

JButton ri=new JButton("右齐");

FlowLayout fl=new FlowLayout();

public first()

{

super("流水版面配置");

c=getContentPane();

c.setLayout(fl);

c.add(le);

c.add(mi);

c.add(ri);

le.addActionListener(this);

mi.addActionListener(this);

ri.addActionListener(this);

setSize(400,200);

setVisible(true);

}

public void actionPerformed(ActionEvent e)

{

String s=e.getActionCommand();

if(s.equals("左齐"))

{

fl.setAlignment(FlowLayout.LEFT);

//this.invalidate();

//c.setLayout(fl);

System.out.println(s);

}

else

if(s.equals("居中"))

{

fl.setAlignment(FlowLayout.CENTER);

//this.invalidate();

//c.setLayout(fl);

System.out.println(s);

}

else

{

fl.setAlignment(FlowLayout.RIGHT);

//this.invalidate();

//c.setLayout(fl);

System.out.println(s);

}

}

public static void main(String[] args)

{

first f=new first();

f.addWindowListener(new MyWindowListener());

}

}

其中用到的MyWindowListener这个类的内容如下：

import java.awt.event.*;

public class MyWindowListener implements WindowListener

{

public void windowActivated(WindowEvent e)

{

System.out.println("窗口为活动状态");

}

public void windowClosed(WindowEvent e)

{

System.out.println("窗口为关闭状态");

System.exit(0);

}

public void windowClosing(WindowEvent e)

{

System.out.println("窗口正在关闭");

System.exit(0);

}

public void windowDeactivated(WindowEvent e)

{

System.out.println("窗口不再活动");

}

public void windowDeiconified(WindowEvent e)

{

System.out.println("窗口由最小化变为正常");

}

public void windowIconified(WindowEvent e)

{

System.out.println("窗口为最小化");

}

public void windowOpened(WindowEvent e)

{

System.out.println("窗口首次可见");

}

}

展开