Java - Vertical “FlowLayout” with Horizontal Scrolling

Question

As described in the title, I\'ve been trying to set up sort of a vertical flow layout with horizontal scrolling. The components within the layout will be JLabels. Let me d

Answer 1

Here is the modified VerticalWrapLayout that I used, in case anyone is interested!

package LogicSim;

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

/**
 *  FlowLayout subclass that fully supports wrapping of components.
 */
public class VerticalWrapLayout extends VerticalFlowLayout
{
private Dimension preferredLayoutSize;

/**
* Constructs a new WrapLayout with a left
* alignment and a default 5-unit horizontal and vertical gap.
*/
public VerticalWrapLayout()
{
    super();
}

/**
* Constructs a new FlowLayout with the specified
* alignment and a default 5-unit horizontal and vertical gap.
* The value of the alignment argument must be one of
* WrapLayout, WrapLayout,
* or WrapLayout.
* @param align the alignment value
*/
public VerticalWrapLayout(int align)
{
    super(align);
}

/**
* Creates a new flow layout manager with the indicated alignment
* and the indicated horizontal and vertical gaps.
* 

* The value of the alignment argument must be one of
* WrapLayout, WrapLayout,
* or WrapLayout.
* @param align the alignment value
* @param hgap the horizontal gap between components
* @param vgap the vertical gap between components
*/
public VerticalWrapLayout(int align, int hgap, int vgap)
{
    super(align, hgap, vgap);
}

/**
* Returns the preferred dimensions for this layout given the
* visible components in the specified target container.
* @param target the component which needs to be laid out
* @return the preferred dimensions to lay out the
* subcomponents of the specified container
*/
@Override
public Dimension preferredLayoutSize(Container target)
{
    return layoutSize(target, true);
}

/**
* Returns the minimum dimensions needed to layout the visible
* components contained in the specified target container.
* @param target the component which needs to be laid out
* @return the minimum dimensions to lay out the
* subcomponents of the specified container
*/
@Override
public Dimension minimumLayoutSize(Container target)
{
    Dimension minimum = layoutSize(target, false);
    minimum.height -= (getVgap() + 1);
    return minimum;
}

/**
* Returns the minimum or preferred dimension needed to layout the target
* container.
*
* @param target target to get layout size for
* @param preferred should preferred size be calculated
* @return the dimension to layout the target container
*/
private Dimension layoutSize(Container target, boolean preferred)
{
        synchronized (target.getTreeLock())
        {
    //  Each row must fit with the width allocated to the containter.
    //  When the container width = 0, the preferred width of the container
    //  has not yet been calculated so lets ask for the maximum.

    int targetHeight = target.getSize().height;

    if (targetHeight == 0)
        targetHeight = Integer.MAX_VALUE;

    int hgap = getHgap();
    int vgap = getVgap();
    Insets insets = target.getInsets();
    int verticalInsetsAndGap = insets.top + insets.bottom + (vgap * 2);
    int maxHeight = targetHeight - verticalInsetsAndGap;

    //  Fit components into the allowed height

    Dimension dim = new Dimension(0, 0);
    int rowWidth = 0;
    int rowHeight = 0;

    int nmembers = target.getComponentCount();

    for (int i = 0; i < nmembers; i++)
    {
        Component m = target.getComponent(i);

        if (m.isVisible())
        {
            Dimension d = preferred ? m.getPreferredSize() : m.getMinimumSize();

            //  Can't add the component to current row. Start a new row.

            if (rowHeight + d.height > maxHeight)
            {
                addColumn(dim, rowWidth, rowHeight);
                rowWidth = 0;
                rowHeight = 0;
            }

            //  Add a horizontal gap for all components after the first

            if (rowHeight != 0)
            {
                rowHeight += vgap;
            }

                            // ******************************************************
            rowHeight += d.height;
                            rowWidth = Math.max(rowWidth, d.width);
        }
    }

    addColumn(dim, rowWidth, rowHeight);

    dim.height += verticalInsetsAndGap;
    dim.width += insets.left + insets.right + hgap * 2;

    //When using a scroll pane or the DecoratedLookAndFeel we need to
    //  make sure the preferred size is less than the size of the
    //  target containter so shrinking the container size works
    //  correctly. Removing the horizontal gap is an easy way to do this.

    Container scrollPane = SwingUtilities.getAncestorOfClass(JScrollPane.class, target);

    if (scrollPane != null)
    {
        dim.height -= (vgap + 1);
    }

    return dim;
}
}

/*
 *  A new row has been completed. Use the dimensions of this row
 *  to update the preferred size for the container.
 *
 *  @param dim update the width and height when appropriate
 *  @param rowWidth the width of the row to add
 *  @param rowHeight the height of the row to add
 */
private void addColumn(Dimension dim, int rowWidth, int rowHeight)
{
    dim.height = Math.max(dim.height, rowHeight);

    if (dim.width > 0)
    {
        dim.width += getHgap();
    }

    dim.width += rowWidth;
}
}

Thanks all!