Question

编写java程序，单击按钮，改变面板的背景色

Answer 1

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

import javax.swing.*;

public class Practise{

public static void main(String[] args) {
new MyFrame();
}
}

class MyFrame extends JFrame
{
public MyFrame()
{
super("改变面板颜色");
final JPanel pan=new JPanel();
pan.setBackground(Color.RED);
JButton btnChangePanColor=new JButton("改变面板颜色");
btnChangePanColor.addActionListener(new ActionListener(){

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
pan.setBackground(Color.GREEN);//改变面板颜色
}

});
pan.setLayout(new FlowLayout());
pan.add(btnChangePanColor);
this.getContentPane().add(pan);
this.setSize(300,300);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//用户单击“关闭”按钮时关闭窗口
this.setResizable(false);
this.setVisible(true);
}
}

Answer 2

JFrame有方法setBackground(Color)