FileDocCategorySizeDatePackage
ColumnLayout.javaAPI DocExample4871Mon Sep 22 13:30:30 BST 1997None

ColumnLayout

public class ColumnLayout extends Object implements LayoutManager2
This LayoutManager arranges the components into a column. Components are always given their preferred size. When you create a ColumnLayout, you may specify four values: margin_height -- how much space to leave on left and right margin_width -- how much space to leave on top and bottom spacing -- how much vertical space to leave between items alignment -- the horizontal position of the components: ColumnLayout.LEFT -- left-justify the components ColumnLayout.CENTER -- horizontally center the components ColumnLayout.RIGHT -- right-justify the components You never call the methods of a ColumnLayout object. Just create one and make it the layout manager for your container by passing it to the addLayout() method of the Container object.

(Omit source code)

Fields Summary
protected int
margin_height
protected int
margin_width
protected int
spacing
protected int
alignment
public static final int
LEFT
public static final int
CENTER
public static final int
RIGHT
Constructors Summary
public ColumnLayout(int margin_height, int margin_width, int spacing, int alignment)
The constructor. See comment above for meanings of these arguments


              
      
                           
    this.margin_height = margin_height;
    this.margin_width = margin_width;
    this.spacing = spacing;
    this.alignment = alignment;
public ColumnLayout()
A default constructor that creates a ColumnLayout using 5-pixel margin width and height, 5-pixel spacing, and left alignment

 this(5, 5, 5, LEFT);
Methods Summary
public voidaddLayoutComponent(java.lang.String constraint, java.awt.Component comp)

public voidaddLayoutComponent(java.awt.Component comp, java.lang.Object constraint)
public floatgetLayoutAlignmentX(java.awt.Container parent)
 return 0.5f; 
public floatgetLayoutAlignmentY(java.awt.Container parent)
 return 0.5f; 
public voidinvalidateLayout(java.awt.Container parent)
public voidlayoutContainer(java.awt.Container parent)
The method that actually performs the layout. Called by the Container
    Insets insets = parent.getInsets();
    Dimension parent_size = parent.getSize();
    Component kid;
    int nkids = parent.getComponentCount();
    int x0 = insets.left + margin_width;
    int x;
    int y = insets.top + margin_height;

    for(int i = 0; i < nkids; i++) {
      kid = parent.getComponent(i);
      if (!kid.isVisible()) continue;
      Dimension pref = kid.getPreferredSize();
      switch(alignment) {
      default:
      case LEFT:   x = x0; break;
      case CENTER: x = x0 + (parent_size.width - pref.width)/2; break;
      case RIGHT:  x = parent_size.width-insets.right-margin_width-pref.width;
                   break;
      }
      kid.setBounds(x, y, pref.width, pref.height);
      y += pref.height + spacing;
    }
  
protected java.awt.DimensionlayoutSize(java.awt.Container parent, int sizetype)
    int nkids = parent.getComponentCount();
    Dimension size = new Dimension(0,0);
    Insets insets = parent.getInsets();
    int num_visible_kids = 0;

    // Compute maximum width and total height of all visible kids
    for(int i = 0; i < nkids; i++) {
      Component kid = parent.getComponent(i);
      Dimension d;
      if (!kid.isVisible()) continue;
      num_visible_kids++;
      if (sizetype == 1) d = kid.getPreferredSize();
      else if (sizetype == 2) d = kid.getMinimumSize();
      else d = kid.getMaximumSize();
      if (d.width > size.width) size.width = d.width;
      size.height += d.height;
    }

    // Now add in margins and stuff
    size.width += insets.left + insets.right + 2*margin_width;
    size.height += insets.top + insets.bottom + 2*margin_height;
    if (num_visible_kids > 1)
      size.height += (num_visible_kids - 1) * spacing;
    return size;
  
public java.awt.DimensionmaximumLayoutSize(java.awt.Container parent)
The Container calls this to find out how big the layout can be
    return layoutSize(parent, 3);
  
public java.awt.DimensionminimumLayoutSize(java.awt.Container parent)
The Container calls this to find out how big the layout must be
    return layoutSize(parent, 2);
  
public java.awt.DimensionpreferredLayoutSize(java.awt.Container parent)
The Container calls this to find out how big the layout should to be
    return layoutSize(parent, 1);
  
public voidremoveLayoutComponent(java.awt.Component comp)