JPanel Scrollable mimic Windows Explorer Icon View

Question

I am developing an image viewer application, and I want my thumbnail image JPanel to mimic MS Windows Explorer's layout in icon view. However, I have not been able to accomplish this. I have searched high and low, finding many others with my same problem, but no solution. To see exactly what I want to mimic, go to Windows Explorer and take a look at Icon View.
Windows Explorer seems to be using a type of FlowLayout, and the icons get wrapped to the next line. If the number of icons exceeds the viewable space, the vertical scrollbar appears. Note that there is no horizontal scrolling; only vertical scrolling with the FlowLayout. If the user adjusts the SplitPane, then the layout adjusts the scrolling and icons accordingly.
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QUESTION: How can I get my JPanel to mimic Windows Explorer Icon View?
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10 Dukes to anyone who can get this to mimic Windows Explorer. Ideally the solution would not be too involved.
P.S. I think it stinks that JPanel, by design, does not implement Scrollable Interface. Even then, it doesn't work the way I want it to with my FlowLayout and only vertical scrolling. Does anyone understand why it doesn't implement Scrollable, like JTextArea, JEditorPane, etc. do?
Thanks
Wayne

Answer 1

Thanks camickr! I didn't try your layout manager since I managed to find another one which seems to do the trick as well. Here is the link from which I found it:
http://groups.google.com/groups?selm=c43ovb%242db505%241%40ID-76750.news.uni-berlin.de&output=gplain
It seems that in the source there is a small bug which is easy to fix. I think the boolean parameters in minimumLayoutSize and preferredLayoutSize should be changed.
So in minimumLayoutSize():
return computeSize(target, true);and in preferredLayoutSize():
return computeSize(target, false);After that fix, it worked just fine for me.
Here is the complete source (author Babu Kalakrishnan):
import java.awt.*;
  * A modified version of FlowLayout that allows containers using this
  * Layout to behave in a reasonable manner when placed inside a
  * JScrollPane
  * @author Babu Kalakrishnan
public class ModifiedFlowLayout extends FlowLayout
     public ModifiedFlowLayout()
         super();
     public ModifiedFlowLayout(int align)
         super(align);
     public ModifiedFlowLayout(int align, int hgap, int vgap)
         super(align, hgap, vgap);
     public Dimension minimumLayoutSize(Container target)
         return computeSize(target, false);
     public Dimension preferredLayoutSize(Container target)
         return computeSize(target, true);
     private Dimension computeSize(Container target, boolean minimum)
         synchronized (target.getTreeLock())
             int hgap = getHgap();
             int vgap = getVgap();
             int w = target.getWidth();
         // Let this behave like a regular FlowLayout (single row)
         // if the container hasn't been assigned any size yet     
             if (w == 0)
                 w = Integer.MAX_VALUE;
             Insets insets = target.getInsets();
             if (insets == null)
                 insets = new Insets(0, 0, 0, 0);
             int reqdWidth = 0;
             int maxwidth = w - (insets.left + insets.right + hgap * 2);
             int n = target.getComponentCount();
             int x = 0;
             int y = insets.top;
             int rowHeight = 0;
             for (int i = 0; i < n; i++)
                 Component c = target.getComponent(i);
                 if (c.isVisible())
                     Dimension d =
                         minimum ? c.getMinimumSize() :      
                      c.getPreferredSize();
                     if ((x == 0) || ((x + d.width) <= maxwidth))
                         if (x > 0)
                             x += hgap;
                         x += d.width;
                         rowHeight = Math.max(rowHeight, d.height);
                     } else
                         x = d.width;
                         y += vgap + rowHeight;
                         rowHeight = d.height;
                     reqdWidth = Math.max(reqdWidth, x);
             y += rowHeight;
             return new Dimension(reqdWidth+insets.left+insets.right, y);
}