dialog empty with JScrollPane und JPanel

May 29, 2022

i am trying to add the content to the mainPanel and mainpanel to the mainScrollPane. However, an empty dialog is displayed.

IMPORTANT: it must be implemented with JPanel and JScrollPane…

   `setModal(true);
    setTitle("Edit item");
    setDefaultCloseOperation(DISPOSE_ON_CLOSE);

    JPanel mainPanel = new JPanel();
    mainPanel.setPreferredSize(new Dimension(400, 700));

    JScrollPane mainScrollPane = new JScrollPane();
    mainScrollPane.add(mainPanel);
    setLayout(new BorderLayout());
    add(mainScrollPane);

    mainPanel.add(new JLabel("ID: "));
    mainPanel.add(txtID = new JTextField(item.getID()));
    mainPanel.add(new JLabel("Description: "));
    mainPanel.add(txtDescription = new JTextField(item.getDescription()));


    pack();
    setVisible(true);`

thank you, guys

>Solution :

Please provide a minimal reproducible example. It could look like what follows:

MyFrame.java

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

class Item { 
    String id; 
    String description; 
    Item(String id, String description) {this.id = id;this.description = description;}
    String getId() {return id;}
    String getDescription() {return description;}
}

public class MyFrame extends JFrame {
    Item item = new Item("007", "Special watch");
    public MyFrame() {
        // setModal(true);
        setTitle("Edit item");
        setDefaultCloseOperation(DISPOSE_ON_CLOSE);

        JPanel mainPanel = new JPanel();
        mainPanel.setPreferredSize(new Dimension(400, 700));

        JScrollPane mainScrollPane = new JScrollPane();
        mainScrollPane.add(mainPanel);
        setLayout(new BorderLayout());
        add(mainScrollPane);

        mainPanel.add(new JLabel("ID: "));
        mainPanel.add(new JTextField(item.getId()));
        mainPanel.add(new JLabel("Description: "));
        mainPanel.add(new JTextField(item.getDescription()));

        getContentPane().add(mainPanel); // <- This makes it shine!

        pack();
        setVisible(true);
    }

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