FileDocCategorySizeDatePackage
TreeLayout.javaAPI DocExample6281Wed Jan 20 13:10:34 GMT 1999None

TreeLayout

public class TreeLayout extends Object implements LayoutManager
Simple layout manager that arranges its children in a tree. The tree always expands to fill the available area, and the internal components are resized to fit the area proportional to their preferred size and the actual available size. This layout manager requires several method calls beyond the normal layout manager. Please notice the following: * Components must be added using the add(String, Component) method. The strings don't have to be unique, but must be present. * Each instance must have exactly one root object, which must be add()ed, then setRoot()ed. * Each component after the root must first be added and then must be connected into the tree using setParent(child, parent). * If you want lines between parents and children, you must call paintLines() from your applet's paint() method.
author
name unknown, xxx@blackdown.org

Fields Summary
TreeNode
root
Hashtable
nodes
Constructors Summary
public TreeLayout()

 nodes = new Hashtable();
Methods Summary
public voidaddLayoutComponent(java.lang.String name, java.awt.Component comp)

    TreeNode tn = new TreeNode(comp);
    nodes.put(comp, tn);
public voidlayoutContainer(java.awt.Container target)

    Insets insets = target.getInsets();
    Dimension d = target.getSize();
    Dimension root_pref = root.getPreferredSize();
    double xscale =
      ((double)(d.width-insets.left-insets.right)/(double)(root_pref.width));
    double yscale =
      ((double)(d.height-insets.top-insets.bottom)/(double)(root_pref.height));
    root.doLayout(xscale, yscale, insets.left, insets.top);
public java.awt.DimensionminimumLayoutSize(java.awt.Container target)

    Dimension d = root.getMinimumSize();
    Insets insets = target.getInsets();
    d.width += insets.left + insets.right;
    d.height += insets.top + insets.bottom;
    return d;
public voidpaintLines(java.awt.Graphics g, java.awt.Color bg)
This piece of hackery is needed since one cant really draw things from a layout manager. Call this if you want to draw lines between components.

    Color dk = bg.darker();
    Color br = bg.brighter();
    root.paintLines(g, dk, br);
public java.awt.DimensionpreferredLayoutSize(java.awt.Container target)

    Dimension d = root.getPreferredSize();
    Insets insets = target.getInsets();
    d.width += insets.left + insets.right;
    d.height += insets.top + insets.bottom;
    return d;
public voidremoveLayoutComponent(java.awt.Component comp)

 nodes.remove(comp);
public voidsetParent(java.awt.Component child, java.awt.Component parent)
Sets the tree parent of a child. The components must have been previously added. If either component has not previously been added, this injunction is silently ignored. Cycles are not checked.

    TreeNode p = (TreeNode) nodes.get(parent);
    TreeNode c = (TreeNode) nodes.get(child);
    if ((p != null) && (c != null))   p.addChild(c);
public voidsetRoot(java.awt.Component c)
You must make this call, otherwise none of the components will be layed out.

 root = (TreeNode) nodes.get(c);