JPanel with BoxLayout and ScrollPane as its Parent

Question

I have a JScrollPane (with both scrollbars optional (should not cause the problem) Inside of the ScrollPane is a panel with BoxLayout and X_Axis - align. (it contains arbitrary number of Panels with fixed (prefference)Size. The Problem is that the ScrollPane will be much wider than necessary (Horizontal Scrollbar scrolls through "grey screen"). With Y_Axis align it works as it should. Relevant code:

final JPanel forSpecific = new JPanel();

    final JScrollPane scrollSpecific = new JScrollPane(forSpecific,
            ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
            ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        forSpecific.setLayout(new BoxLayout(forSpecific,BoxLayout.X_AXIS));

I have no idea whats the poblem and did not find any solution...

EDITED: sry it took some time. The original code was to complex to extract some sscce.. i wrote a test-class. This example works coorect.. but i dont know whats different.. package getdata;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;

import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;


public class Sscce {

public static void gui(){
    final JFrame rootframe = new JFrame("Time Series Mining");
    final JPanel mainPanel = new JPanel(new BorderLayout());
    rootframe.setSize(new Dimension(400,400));
    rootframe.setContentPane(mainPanel);
    mainPanel.setLayout(new BorderLayout());
    JPanel center=new JPanel(new GridLayout(2,1));
    JPanel forSpecific=new JPanel();
    forSpecific.setLayout(new BoxLayout(forSpecific, BoxLayout.X_AXIS));
    JPanel test1 = new JPanel();
    test1.setPreferredSize(new Dimension(1000,1000));
    forSpecific.add(test1);
    test1.setBackground(Color.white);
    final JScrollPane scrollSpecific = new JScrollPane(forSpecific);
    center.add(scrollSpecific);
    rootframe.add(center, BorderLayout.CENTER);
    rootframe.setVisible(true);
}
}

and added to its parent (A JPanel With GridLayout(2,1).. as second entry: centerPanel.add(scrollSpecific); — Jan S, Jun 08 '13 at 00:02
@JanS, means noting without a `SSCCE!`. Most of the time as you attempt to create the SSCCE you will find your problem. — camickr, Jun 08 '13 at 00:03
However.. I shanged the BoxLayout with "X-directon" to FlowLayout. Makes sence until it is nearly same. Can i trust in this Layout to have a look on childcomponents XAlinement,YAlignment and prefered size?.. I hate jawa gui... — Jan S, Jun 08 '13 at 01:26
`This example works coorect` - which shows that if you code your program correctly it will work. Only you can solve your problem because we don't know what your code looks like. As I have already stated, generally you will have problems if you hard code the preferred size of a component. So that would be the first place to look. — camickr, Jun 08 '13 at 01:44

camickr · Accepted Answer · 2013-06-08T00:20:57.737

//final JScrollPane scrollSpecific = new JScrollPane(forSpecific,
//    ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
//    ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
final JScrollPane scrollSpecific = new JScrollPane(forSpecific);

Not the problem but the "scrollbar as needed" is the default. You don't need to specify this.

Inside of the ScrollPane is a panel with BoxLayout and X_Axis - align. (it contains arbitrary number of Panels with fixed (prefference)Size.

What is a fixed size?

the "main" panel added to the scrollpane
the "child" panels added to the main panel

In any case the size should not be fixed, the layout manager should determine the preferred size. Or if you are creating a custom component then you should override the getPreferredSize() method to return the proper size so the layout manager can do its job.

JPanel with BoxLayout and ScrollPane as its Parent

1 Answers1