CODEWITHSUNDEEP
javaswing
Alex Bliskovsky
Alex Bliskovsky

Reputation: 6303

Items not Appearing in New Frame in Java

I'm building a JFrame that will eventually display the output of a program that has a variable number of sections in it. I have parsed the output but displaying it in the frame is a problem.

When the frame appears, it is completely empty with the exception of the scroll pane. How do I get these labels to show up?

public class OutputPanel extends JFrame {

    public OutputPanel(Vector parsedOutput) {

    this.setTitle("Output");
    this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

    JScrollPane scrollPane = new JScrollPane();

    Iterator<Vector> outputIter = parsedOutput.iterator();

    while(outputIter.hasNext()) {
        Vector section = outputIter.next();

        JLabel sectionLabel = new JLabel((String)section.get(0));
        System.out.println((String)section.get(0));
        scrollPane.add(sectionLabel);

    }
    this.add(scrollPane);
    this.pack();
    this.setVisible(true);

    }
}

Upvotes: 1

Views: 215

Answers (2)

aioobe
aioobe

Reputation: 421040

You shouldn't add components to the scrollPane

scrollPane.add(sectionLabel);

but rather add them to a separate panel, and either use

scrollPane = new JScrollPane(thePanel);

or

scrollPane.setViewportView(thePanel);

Example:

import java.awt.GridLayout;
import java.util.Vector;

import javax.swing.*;

class Test {
    public static void main(String[] args) {
        new OutputPanel(null);
    }
}

class OutputPanel extends JFrame {

    public OutputPanel(Vector parsedOutput) {

        this.setTitle("Output");
        this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel content = new JPanel(new GridLayout(0, 1));

        for (int i = 0; i < 100; i++) {    
            JLabel sectionLabel = new JLabel("hello " + i);
            content.add(sectionLabel);
        }
        JScrollPane scrollPane = new JScrollPane(content);

        this.add(scrollPane);
        this.pack();
        this.setVisible(true);

    }
}

Produces:

enter image description here

Upvotes: 2

Bala R
Bala R

Reputation: 108957

You should use setViewPortView() with a container instead of add() for JScrollPane.

Try this.

public class OutputPanel extends JFrame {

    public OutputPanel(Vector parsedOutput) {

    this.setTitle("Output");
    this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

    JScrollPane scrollPane = new JScrollPane();

    Iterator<Vector> outputIter = parsedOutput.iterator();
    JPanel panel = new JPanel();
    panel.setLayout(new FlowLayout());
    scrollPane.setViewportView(panel);
    while(outputIter.hasNext()) {

        Vector section = outputIter.next();

        JLabel sectionLabel = new JLabel((String)section.get(0));
        System.out.println((String)section.get(0));
        panel.add(sectionLabel);

    }
    this.add(scrollPane);
    this.pack();
    this.setVisible(true);

    }
}

Upvotes: 2

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