CODEWITHSUNDEEP
javaswinguser-interfacejframejpanel
Alex Brown
Alex Brown

Reputation: 35

How to add a JPanel to a JFrame object?

Beginner programming student here. Trying to simply create JFrame object that allows me to click on the boundaries of the window and display the coordinates where I click. However, whenever I click a new location, the previous coordinates need to disappear. I have been told that one way to do this is by adding a JPanel to the center of the JFrame object. However when I do so I am getting an error that says that I am adding a window to a container. I may be extending something incorrectly from what I have read but I can't seem to figure it out.

public class Proj07 {
    public static void main(String[] args){
        new Proj07Runner();
      }
    }

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

class Proj07Runner{
    
    GUI gui = new GUI();
}

class MyFrame extends JFrame{
    int XCoor;
    int YCoor;
    
    public void paint(Graphics g){
        g.drawString("x = " + XCoor + ", y = " + YCoor, XCoor, YCoor);
    }
}

class GUI{
    public GUI(){
        MyFrame displayWindow = new MyFrame();
        displayWindow.setSize(300,100);
        displayWindow.setTitle("Insert name here");
        displayWindow.addWindowListener(new WProc1());
        
        JPanel myPanel = new JPanel();
        displayWindow.getContentPane().add(myPanel, "Center");
        displayWindow.setVisible(true);
        }
}

class MouseProc extends MouseAdapter{
    
    
    public void mousePressed(MouseEvent e){
    ((MyFrame)e.getComponent()).XCoor = e.getX();
    ((MyFrame)e.getComponent()).YCoor = e.getY();
    
    e.getComponent().repaint();
    }
}

class WProc1 extends WindowAdapter{
    public void windowClosing(WindowEvent e){
        System.exit(0);
    }
}

Thank you guys for your help!

Upvotes: 0

Views: 202

Answers (1)

The Blind Hawk
The Blind Hawk

Reputation: 1656

I am not 100% sure but I think the problem is where you put the listener:

You need to do everything on the JPanel, not the frame that is the container, so you should replace the declares with:

    MyFrame displayWindow = new MyFrame();
    displayWindow.setSize(300,100);
    displayWindow.setTitle("Insert name here");
    displayWindow.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    JPanel myPanel = new JPanel();
    myPanel.setSize(300,100);
    myPanel.addMouseListener(new myMouse)
    displayWindow.getContentPane().add(myPanel, "Center");
    displayWindow.setVisible(true);

And then create a mouseListener instead of a mouseAdapter to add in the JPanel.
Also remove the last WindowsAdapter thing, just use exitonclose.

Edit:
When it comes down to what the frame should do it should only contain the panel, so you also need to move everything you were doing on the frame to the panel (such as the public void paint() and stuff).
I would go as far as saying that if you want to add multiple panels on a frame, you should consider putting all panels inside another panel (as a container) and then putting that panel inside the frame.

Upvotes: 1

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