jf.add(this)是什么意思,我理解的是在jf对象中添加个什么
就一直不知道jf.add(this)是什么意思,没有这句代码显示图片的时候出错误,下面是别人给我发过来测试用的
package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class Frame1 extends JPanel implements ActionListener {
JFrame jf;
JButton start;
public Frame1(){
jf = new JFrame("开始游戏界面");
this.setBackground(Color.BLUE);
start = new JButton("开始游戏");
start.addActionListener(this);
this.add(start);
jf.add(this);
jf.setSize(800,800);
jf.setLocationRelativeTo(null);
jf.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
jf.addWindowListener(new window());
jf.setVisible(true);
}
class window extends WindowAdapter {
public void windowClosing(WindowEvent e) {
int clo= JOptionPane.showConfirmDialog(jf,"你真的真的真的决定要离开吗?","退出游戏",JOptionPane.YES_NO_OPTION);
if(clo==JOptionPane.YES_OPTION) {
System.exit(0);
}
}
}
public static void main(String[] args) {
new Frame1();
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == start){
jf.dispose();
new Frame2();
}
}