Custom layout: EdgeLayout
/*
Code from Desktop Java Live Source
URL: http://www.sourcebeat.com/downloads/
*/
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager2;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class EdgeLayoutExample {
public static JPanel createPanel() {
JPanel outerPanel = new JPanel();
outerPanel.setLayout(new EdgeLayout());
outerPanel.add(new JButton("West1"), EdgeLayout.WEST);
outerPanel.add(new JButton("North1"), EdgeLayout.NORTH);
outerPanel.add(new JButton("West2"), EdgeLayout.WEST);
outerPanel.add(new JButton("North2"), EdgeLayout.NORTH);
outerPanel.add(new JButton("East1"), EdgeLayout.EAST);
outerPanel.add(new JButton("South1"), EdgeLayout.SOUTH);
outerPanel.add(new JButton("West3"), EdgeLayout.WEST);
outerPanel.add(new JButton("West4"), EdgeLayout.WEST);
outerPanel.add(new JButton("South2"), EdgeLayout.SOUTH);
outerPanel.add(new JButton("South3"), EdgeLayout.SOUTH);
outerPanel.add(new JButton("Center1"), EdgeLayout.CENTER);
return outerPanel;
}
public static void main(String[] a){
JFrame f = new JFrame();
f.setDefaultCloseOperation(1);
f.add(createPanel());
f.pack();
f.setVisible(true);
}
}
class EdgeLayout implements LayoutManager2, java.io.Serializable {
private List components = new ArrayList();
private HashMap constraints = new HashMap();
public static final String CENTER = "center";
public static final String NORTH = "north";
public static final String SOUTH = "south";
public static final String EAST = "east";
public static final String WEST = "west";
public void addLayoutComponent(Component comp, Object constraints) {
synchronized (comp.getTreeLock()) {
if (constraints instanceof String && comp != null) {
this.components.add(comp);
this.constraints.put(comp, constraints);
} else {
throw new IllegalArgumentException("Invalid component constraints.");
}
}
}
public Dimension maximumLayoutSize(Container target) {
//Return a very large size since this layout manager will fill all available space.
return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
}
public float getLayoutAlignmentX(Container target) {
//Centered on the X
return (float) 0.5;
}
public float getLayoutAlignmentY(Container target) {
//Centered on the Y
return (float) 0.5;
}
public void invalidateLayout(Container target) {
//There is no caching in EdgeLayout to there is nothing to invalidate
}
public void addLayoutComponent(String name, Component comp) {
throw new IllegalArgumentException("EdgeLayout only supports addition with contraints.");
}
public void removeLayoutComponent(Component comp) {
synchronized (comp.getTreeLock()) {
this.components.remove(comp);
this.constraints.remove(comp);
}
}
public Dimension preferredLayoutSize(Container parent) {
synchronized (parent.getTreeLock()) {
int width = 0;
int height = 0;
//Add the preferred widths of all EAST/WEST components
//Add the preferred height of all NORTH/SOUTH components
for (int i = 0; i < this.components.size(); i++) {
Component c = (Component) this.components.get(i);
if (this.constraints.get(c).equals(WEST) || this.constraints.get(c).equals(EAST)) {
width += c.getPreferredSize().getWidth();
} else {
height += c.getPreferredSize().getHeight();
}
}
width += parent.getInsets().right + parent.getInsets().left;
height += parent.getInsets().top + parent.getInsets().bottom;
return new Dimension(width, height);
}
}
public Dimension minimumLayoutSize(Container parent) {
synchronized (parent.getTreeLock()) {
int width = 0;
int height = 0;
//Add the minimum widths of all EAST/WEST components
//Add the minimum height of all NORTH/SOUTH components
for (int i = 0; i < this.components.size(); i++) {
Component c = (Component) this.components.get(i);
if (this.constraints.get(c).equals(WEST) || this.constraints.get(c).equals(EAST)) {
width += c.getMinimumSize().getWidth();
} else {
height += c.getMinimumSize().getHeight();
}
}
width += parent.getInsets().right + parent.getInsets().left;
height += parent.getInsets().top + parent.getInsets().bottom;
return new Dimension(width, height);
}
}
public void layoutContainer(Container parent) {
synchronized (parent.getTreeLock()) {
Insets insets = parent.getInsets();
int top = insets.top;
int left = insets.left;
Dimension minimumSize = minimumLayoutSize(parent);
int height = minimumSize.height;
int width = minimumSize.width;
int availableHeight = parent.getHeight() - insets.bottom - insets.top;
int availableWidth = parent.getWidth() - insets.left - insets.right;
if (height < availableHeight) {
height = availableHeight;
}
if (width < availableWidth) {
width = availableWidth;
}
int bottom = availableHeight;
int right = availableWidth;
Dimension preferredSize = preferredLayoutSize(parent);
int preferredWidthAvailable = width - preferredSize.width;
int preferredHeightAvailable = height - preferredSize.height;
Component centerComp = null;
for (int i = 0; i < this.components.size(); i++) {
Component c = (Component) this.components.get(i);
String constraint = (String) this.constraints.get(c);
if (constraint.equals(CENTER)) {
centerComp = c;
} else {
int compHeight;
int compWidth;
int xOrigin;
int yOrigin;
if (constraint.equals(NORTH) || constraint.equals(SOUTH)) {
compWidth = width;
if (preferredHeightAvailable > 0) {
int preferredHeightNeeded = c.getPreferredSize().height - c.getMinimumSize().height;
if (preferredHeightAvailable > preferredHeightNeeded) {
compHeight = c.getPreferredSize().height;
preferredHeightAvailable -= preferredHeightNeeded;
} else {
compHeight = c.getMinimumSize().height + preferredHeightAvailable;
preferredHeightAvailable = 0;
}
} else {
compHeight = c.getMinimumSize().height;
}
height = height - compHeight;
xOrigin = left;
if (constraint.equals(NORTH)) {
yOrigin = top;
top += compHeight;
} else {
yOrigin = bottom - compHeight;
bottom = yOrigin;
}
} else {
compHeight = height;
if (preferredWidthAvailable > 0) {
int preferredWidthNeeded = c.getPreferredSize().width - c.getMinimumSize().width;
if (preferredWidthAvailable > preferredWidthNeeded) {
compWidth = c.getPreferredSize().width;
preferredWidthAvailable -= preferredWidthNeeded;
} else {
compWidth = c.getMinimumSize().width + preferredWidthAvailable;
preferredWidthAvailable = 0;
}
} else {
compWidth = c.getMinimumSize().width;
}
width = width - compWidth;
yOrigin = top;
if (constraint.equals(WEST)) {
xOrigin = left;
left += compWidth;
} else {
xOrigin = right - compWidth;
right = xOrigin;
}
}
c.setSize(compWidth, compHeight);
c.setBounds(xOrigin, yOrigin, compWidth, compHeight);
}
if (centerComp != null) {
c.setSize(width, height);
c.setBounds(left, top, width, height);
}
}
}
}
}
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