JPanels之间的沟通

Question

I have a JPanel class that creates a panel1 and a panel2. Panel1 and Panel2 both have one button each. What I'm trying to accomplish is when I click on the button in Panel1 that it updates the button in Panel2. I have to do this without changing anything in Panel2. Basically I have to have Panel1 have a way to keep track of an instance of Panel2 and I would have to do this through the JPanel class. But I have no clue where to begin on even accomplishing this.

myJPanel.java

import java.awt.*;
import javax.swing.*;

public class myJPanel extends JPanel
{
public myJPanel()
{
    super();
    setBackground(Color.gray);

    setLayout(new BorderLayout());

    myJPanel1 p1 = new myJPanel1();
    add(p1,"North");
    myJPanel2 p2 = new myJPanel2();
    add(p2,"Center");



}
}

myJPanel1.java

import java.awt.*;
import javax.swing.*;

public class myJPanel1 extends JPanel
{

public myJPanel1()
{
    super();
    setBackground(Color.yellow);

    student st1 = new student("Clark","Fontaa",26);
    // the whatsUp of this student has to shown in the other panel

    JButton jl1 = new JButton(st1.getInfo());
    add(jl1);
}
}

myJPanel2.java

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class myJPanel1 extends JPanel implements ActionListener
{

student st1 = new student("Fred","Fonseca",44);
JButton jl1;
public myJPanel1()
{
    super();
    setBackground(Color.yellow);

    jl1 = new JButton(st1.getInfo());
            jl1.addActionListener(this);
    add(jl1);
}

    public void actionPerformed(ActionEvent event){
        Object obj = event.getSource();
        if (obj == jl1){
        // something here
        }
    }

Thanks for any help!

Answer 1

Add a new field in myJPanel1 class of type Panel so you have reference of the Jpanel2, so that you could further play around with it without changing anything in Panel 2. So follow these steps:

1. Add new field called Panel panel2, and in constructor add Panel parameter like myJPanel1(JPanel panel) {//set local panel2 instance variable now}

2. In your myJPanel class, change the following:

    myJPanel1 p1 = new myJPanel1(); add(p1,"North"); myJPanel2 p2 = new myJPanel2(); add(p2,"Center"); 

   To

    myJPanel2 p2 = new myJPanel2(); add(p2,"Center"); myJPanel1 p1 = new myJPanel1(p2);//reverse the order of panel instantiation and pass p2 to panel1. add(p1,"North"); 

3. Now you have reference to p2 in p1, if you if you could anything you like.

4. Use equals method to do comparison instead of ==