A vertical layout manager similar to java.awt.FlowLayout
/**
THIS PROGRAM IS PROVIDED "AS IS" WITHOUT ANY WARRANTIES (OR CONDITIONS),
EXPRESS OR IMPLIED WITH RESPECT TO THE PROGRAM, INCLUDING THE IMPLIED WARRANTIES (OR CONDITIONS)
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK ARISING OUT OF USE OR
PERFORMANCE OF THE PROGRAM AND DOCUMENTATION REMAINS WITH THE USER.
*/
import java.awt.*; import java.util.*;
/**
*
* A vertical layout manager similar to java.awt.FlowLayout.
* Like FlowLayout components do not expand to fill available space except when the horizontal alignment
* is <code>BOTH</code>
* in which case components are stretched horizontally. Unlike FlowLayout, components will not wrap to form another
* column if there isn't enough space vertically. VerticalLayout can optionally anchor components to the top or bottom
* of the display area or center them between the top and bottom.
*
* Revision date 12th July 2001
*
* @author Colin Mummery e-mail: colin_mummery@yahoo.com Homepage:www.kagi.com/equitysoft -
* Based on 'FlexLayout' in Java class libraries Vol 2 Chan/Lee Addison-Wesley 1998
*/
public class VerticalLayout implements LayoutManager{
/**
* The horizontal alignment constant that designates centering. Also used to designate center anchoring.
*/
public final static int CENTER=0;
/**
* The horizontal alignment constant that designates right justification.
*/
public final static int RIGHT=1;
/**
* The horizontal alignment constant that designates left justification.
*/
public final static int LEFT=2;
/**
* The horizontal alignment constant that designates stretching the component horizontally.
*/
public final static int BOTH=3;
/**
* The anchoring constant that designates anchoring to the top of the display area
*/
public final static int TOP=1;
/**
* The anchoring constant that designates anchoring to the bottom of the display area
*/
public final static int BOTTOM=2;
private int vgap; //the vertical vgap between components...defaults to 5
private int alignment; //LEFT, RIGHT, CENTER or BOTH...how the components are justified
private int anchor; //TOP, BOTTOM or CENTER ...where are the components positioned in an overlarge space
private Hashtable comps;
//Constructors
/**
* Constructs an instance of VerticalLayout with a vertical vgap of 5 pixels, horizontal centering and anchored to
* the top of the display area.
*/
public VerticalLayout(){
this(5,CENTER,TOP);
}
/**
* Constructs a VerticalLayout instance with horizontal centering, anchored to the top with the specified vgap
*
* @param vgap An int value indicating the vertical seperation of the components
*/
public VerticalLayout(int vgap){
this(vgap,CENTER,TOP);
}
/**
* Constructs a VerticalLayout instance anchored to the top with the specified vgap and horizontal alignment
*
* @param vgap An int value indicating the vertical seperation of the components
* @param alignment An int value which is one of <code>RIGHT, LEFT, CENTER, BOTH</code> for the horizontal alignment.
*/
public VerticalLayout(int vgap,int alignment){
this(vgap,alignment,TOP);
}
/**
* Constructs a VerticalLayout instance with the specified vgap, horizontal alignment and anchoring
*
* @param vgap An int value indicating the vertical seperation of the components
* @param alignment An int value which is one of <code>RIGHT, LEFT, CENTER, BOTH</code> for the horizontal alignment.
* @param anchor An int value which is one of <code>TOP, BOTTOM, CENTER</code> indicating where the components are
* to appear if the display area exceeds the minimum necessary.
*/
public VerticalLayout(int vgap,int alignment,int anchor){
this.vgap=vgap; this.alignment=alignment; this.anchor=anchor;
}
//----------------------------------------------------------------------------
private Dimension layoutSize(Container parent,boolean minimum){
Dimension dim=new Dimension(0,0);
Dimension d;
synchronized(parent.getTreeLock()){
int n=parent.getComponentCount();
for(int i=0;i<n;i++){
Component c=parent.getComponent(i);
if(c.isVisible()){
d=minimum ? c.getMinimumSize() : c.getPreferredSize();
dim.width=Math.max(dim.width,d.width); dim.height+=d.height;
if(i>0)dim.height+=vgap;
}
}
}
Insets insets=parent.getInsets();
dim.width+=insets.left+insets.right;
dim.height+=insets.top+insets.bottom+vgap+vgap;
return dim;
}
//-----------------------------------------------------------------------------
/**
* Lays out the container.
*/
public void layoutContainer(Container parent){
Insets insets=parent.getInsets();
synchronized(parent.getTreeLock()){
int n=parent.getComponentCount();
Dimension pd=parent.getSize(); int y=0;
//work out the total size
for(int i=0;i<n;i++){
Component c=parent.getComponent(i);
Dimension d=c.getPreferredSize();
y+=d.height+vgap;
}
y-=vgap; //otherwise there's a vgap too many
//Work out the anchor paint
if(anchor==TOP)y=insets.top;
else if(anchor==CENTER)y=(pd.height-y)/2;
else y=pd.height-y-insets.bottom;
//do layout
for(int i=0;i<n;i++){
Component c=parent.getComponent(i);
Dimension d=c.getPreferredSize();
int x=insets.left; int wid=d.width;
if(alignment==CENTER)x=(pd.width-d.width)/2;
else if(alignment==RIGHT)x=pd.width-d.width-insets.right;
else if(alignment==BOTH)wid=pd.width-insets.left-insets.right;
c.setBounds(x,y,wid,d.height);
y+=d.height+vgap;
}
}
}
//-----------------------------------------------------------------------------
public Dimension minimumLayoutSize(Container parent){return layoutSize(parent,false);}
//-----------------------------------------------------------------------------
public Dimension preferredLayoutSize(Container parent){return layoutSize(parent,false);}
//----------------------------------------------------------------------------
/**
* Not used by this class
*/
public void addLayoutComponent(String name,Component comp){}
//-----------------------------------------------------------------------------
/**
* Not used by this class
*/
public void removeLayoutComponent(Component comp){}
//-----------------------------------------------------------------------------
public String toString(){return getClass().getName()+"[vgap="+vgap+" align="+alignment+" anchor="+anchor+"]";}
}
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