Code
class ScrollableWrapLayout extends FlowLayout {
private final int fixedHorizontalGap;
protected ScrollableWrapLayout(int align, int hgap, int vgap) {
super(align, hgap, vgap);
fixedHorizontalGap = hgap;
}
private int getPreferredHorizontalGap(Container target) {
Insets insets = target.getInsets();
int columns = 0;
int width = target.getWidth();
if (target.getParent() instanceof JViewport) {
width = target.getParent().getBounds().width;
}
width -= insets.left + insets.right + fixedHorizontalGap * 2;
for (int i = 0; i < target.getComponentCount(); i++) {
Component m = target.getComponent(i);
if (m.isVisible()) {
Dimension d = m.getPreferredSize();
if (width - d.width - fixedHorizontalGap < 0) {
columns = i;
break;
}
width -= d.width + fixedHorizontalGap;
}
}
return fixedHorizontalGap + width / columns;
}
@Override public void layoutContainer(Container target) {
setHgap(getPreferredHorizontalGap(target));
super.layoutContainer(target);
}
@Override public Dimension preferredLayoutSize(Container target) {
Dimension dim = super.preferredLayoutSize(target);
synchronized (target.getTreeLock()) {
if (target.getParent() instanceof JViewport) {
dim.width = target.getParent().getBounds().width;
for (int i = 0; i < target.getComponentCount(); i++) {
Component m = target.getComponent(i);
if (m.isVisible()) {
Dimension d = m.getPreferredSize();
dim.height = Math.max(dim.height, d.height + m.getY());
}
}
}
return dim;
}
}
}
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