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ColumnLayout.javaAPI DocExample5400Sat Jan 24 10:44:32 GMT 2004je3.gui

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 top and bottom margin_width -- how much space to leave on left and right 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.

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;  // The base X position
	int x;
	int y = insets.top + margin_height;   // Start at the top of the column
	
	for(int i = 0; i < nkids; i++) {      // Loop through the kids
	    kid = parent.getComponent(i);     // Get the kid
	    if (!kid.isVisible()) continue;   // Skip hidden ones
	    Dimension pref = kid.getPreferredSize();  // How big is it?
	    switch(alignment) {               // Compute X coordinate
	    default:
	    case LEFT:   x = x0; break;
	    case CENTER: x = (parent_size.width - pref.width)/2; break;
	    case RIGHT:
		x = parent_size.width-insets.right-margin_width-pref.width;
		break;
	    }
	    // Set the size and position of this kid
	    kid.setBounds(x, y, pref.width, pref.height);
	    y += pref.height + spacing;       // Get Y position of the next one
	}
    
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)