Java applet scrollbar

Question

[Thanks for the answers. This comes for you http://www.youtube.com/watch?v=Vo0Cazxj_yc ] This might and should be a very easy question, but i could not find a solution.

I have a java applet, and i want a vertical scrollbar so that i can load thousands of buttons into the applet and use the scrollbar to see buttons down on the applet rightnow it looks like this .

Buttons are used to select items. if button is pressed, the item is selected.

When i load buttons, all of them are shown on one screen, squeezed together to fit the screen in width and height (~1000px,~1000px). Below code is a portion of my program. Please comment.

    JFrame frame = new JFrame();
    NameClassifier nameClassifier = new NameClassifier();
    JScrollPane scrollPane = new JScrollPane(nameClassifier);
     scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    frame.add(scrollPane);
    frame.getContentPane().add(nameClassifier);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
    System.out.println("exiting");

For better help sooner. post an SSCCE. Note that I completed an SSCCE from your snippets in around 35 lines of code. — Andrew Thompson
– Andrew Thompson, Commented May 2, 2011 at 3:33
BTW - why do you make continual references to 'applet' when the code uses a 'frame'? — Andrew Thompson
– Andrew Thompson, Commented May 2, 2011 at 3:37
"thousands of buttons .. used to select items." That sounds like it is better suited to a JList component with multiple selection enabled. — Andrew Thompson
– Andrew Thompson, Commented May 2, 2011 at 6:04
Andrew You are right, I should have added the NameClassifier part. Also, This is the first time I had to use Applets, I do not know the difference between them and frames — cuneyt
– cuneyt, Commented May 2, 2011 at 8:44
An applet is (usually) embedded in a web page. A Frame or JFrame is free floating on the desktop. I strongly suggest you avoid applets if at all possible. — Andrew Thompson
– Andrew Thompson, Commented May 2, 2011 at 8:59

Andrew Thompson · Accepted Answer · 2011-05-02 04:34:27Z

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

class ManyButtons {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new JFrame();
                NameClassifier nameClassifier = new NameClassifier();
                JScrollPane scrollPane = new JScrollPane(nameClassifier);
                scrollPane.setVerticalScrollBarPolicy(
                    ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
                frame.add(scrollPane);
                // nameClassifier has already been added to the scroll pane.
                //frame.getContentPane().add(nameClassifier);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setVisible(true);
                System.out.println("exiting");
            }
        });
    }
}

class NameClassifier extends JPanel {

    NameClassifier() {
        super(new GridLayout(0,10,2,2));
        for (int ii=1; ii<=1000; ii++) {
            add(new JButton("Button " + ii));
        }
    }
}

camickr · Accepted Answer · 2011-05-01 21:09:37Z

1

I think you want to use a Wrap Layout.

answered May 1, 2011 at 21:09

camickr

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Comments

MeBigFatGuy · Accepted Answer · 2011-05-01 19:26:59Z

0

Don't add anything directly to the frame, so

frame.add(scrollPane);

is wrong.

Add things to the content pane. probably

scrollPane.add(nameClassifier);
frame.getContentPane().add(scrollPane);

btw, that is one pretty gui design. :)

answered May 1, 2011 at 19:26

MeBigFatGuy

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2 Comments

camickr Over a year ago

-1, it is not wrong to add components directly to the frame. This has been supported since JDK5.

cuneyt Over a year ago

MeBigFatGuy, I would love to share this great design with the world, but alas only I will use it.

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