JScrollPane viewport size question

Question

Hi all,
I've a component that is very large (it has a dinamic height) but its width is always the same (fixed). I need to show this component in a JScrollPane container and only shows the vertical scrollbar. It works fine but when my applications runs, the component inside the JScrollPane (yes..my component) get a different width, which is larger than the original componet's width
I'm using the following code:
        JScrollPane scroll = new JScrollPane(myComponent);
        scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);My question is, How I can do for set a fixed width to the JScrollPane (its viewport or its child component) in order to get the correct component width and only allows a dinamic height ?
thanks in advance

Answer 1

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Random;
public class Test3 extends JFrame {
  JPanel jp = new JPanel();
  JScrollPane jsp = new JScrollPane(jp);
  JLabel jl = new JLabel("", JLabel.CENTER);
  Random rand = new Random();
  public Test3(){
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container content = getContentPane();
    content.add(jl, BorderLayout.NORTH);
    jp.setBorder(BorderFactory.createLineBorder(Color.blue));
    jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
    jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
    content.add(jsp, BorderLayout.CENTER);
    JButton jb = new JButton("Random Height");
    content.add(jb, BorderLayout.SOUTH);
    jb.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent ae) {
        int height = rand.nextInt(1000);
        jp.setPreferredSize(new Dimension(jsp.getViewport().getWidth(),height));
        jsp.getViewport().revalidate();
        jl.setText(""+height);
    setSize(300,300);
  public static void main(String[] args) {new Test3().setVisible(true); }
}