centrallayout.java

PIY(Program It Yourself)是一个基于Java的应用程序开发环境

package piy;

import java.awt.*;

/**
* Aligns a single component in a container so that it is centered vertically, but is 
* stretched to fill all the available horizontal space.  The component's preferred size
* is used to determine the height used.
*
* @author David Vivash
* @version 1.0.1, 22/04/01
*/
public class CentralLayout implements LayoutManager {
	private Component toAlign = null;

	/**
	* Adds the specified component with the specified name to the layout. 
	* @param name the name of the component (NOT USED)
	* @param comp the component to add
	*/
	public void addLayoutComponent(String name, Component comp) {
		toAlign = comp;
	}
	
	/**
	* Lays out the container in the specified panel.
	* @param parent the container's parent
	*/
	public void layoutContainer(Container parent) {
		if (toAlign != null) {
			Dimension pSize = parent.getSize();
			Dimension compSize = toAlign.getPreferredSize();
			toAlign.setBounds(0,(int)(pSize.getHeight()/2-compSize.getHeight()/2), (int)pSize.getWidth(), (int)compSize.getHeight());
		}
		parent.repaint();
	}

	/**
	* Calculates the minimum size dimensions for the specified panel given the components 
	* in the specified parent container. THIS IS NOT USED.
	* @param parent the container's parent
	* @return the size requirements of the container 
	*/
	public Dimension minimumLayoutSize(Container parent) {
		return (toAlign == null) ? new Dimension(0,0) : toAlign.getPreferredSize();
	}
	
	/**
	* Calculates the preferred size dimensions for the specified panel given the components 
	* in the specified parent container. THIS IS NOT USED.
	* @param parent the component's parent
	* @return the size requirements of the container
	*/
	public Dimension preferredLayoutSize(Container parent) {
		return (toAlign == null) ? new Dimension(0,0) : toAlign.getPreferredSize();
	}
	
	/**
	* Removes the specified component from the layout. 
	* @param comp the component to remove
	*/
	public void removeLayoutComponent(Component comp) {
		if (comp == toAlign) toAlign = null;
	}
}