Category Tree
/******************************************************************************
* Copyright (c) 1998, 2004 Jackwind Li Guojie
* All right reserved.
*
* Created on Dec 28, 2003 7:56:40 PM by JACK
* $Id$
*
* visit: http://www.asprise.com/swt
*****************************************************************************/
import java.util.Vector;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;
public class CategoryTree {
Display display = new Display();
Shell shell = new Shell(display);
final Tree tree = new Tree(shell, SWT.BORDER);
Vector categories = new Vector();
public CategoryTree() {
Category category = new Category("Java libraries", null);
categories.add(category);
category = new Category("UI Toolkits", category);
new Category("AWT", category);
new Category("Swing", category);
new Category("SWT/JFace", category);
category = new Category("Java IDEs", null);
categories.add(category);
new Category("Eclipse", category);
new Category("JBuilder", category);
}
/**
* Builds up the tree with traditional approach.
*
*/
public void traditional() {
for(int i=0; categories != null && i < categories.size(); i++) {
Category category = (Category)categories.elementAt(i);
addCategory(null, category);
}
}
/**
* Adds a category to the tree (recursively).
* @param parentItem
* @param category
*/
private void addCategory(TreeItem parentItem, Category category) {
TreeItem item = null;
if(parentItem == null)
item = new TreeItem(tree, SWT.NONE);
else
item = new TreeItem(parentItem, SWT.NONE);
item.setText(category.getName());
Vector subs = category.getSubCategories();
for(int i=0; subs != null && i < subs.size(); i++)
addCategory(item, (Category)subs.elementAt(i));
}
/**
* Builds up the tree with MVC approach.
*
*/
public void MVC() {
TreeViewer treeViewer = new TreeViewer(tree);
treeViewer.setContentProvider(new ITreeContentProvider() {
public Object[] getChildren(Object parentElement) {
Vector subcats = ((Category)parentElement).getSubCategories();
return subcats == null ? new Object[0] : subcats.toArray();
}
public Object getParent(Object element) {
return ((Category)element).getParent();
}
public boolean hasChildren(Object element) {
return ((Category)element).getSubCategories() != null;
}
public Object[] getElements(Object inputElement) {
if(inputElement != null && inputElement instanceof Vector) {
return ((Vector)inputElement).toArray();
}
return new Object[0];
}
public void dispose() {
//
}
public void inputChanged(Viewer viewer,
Object oldInput,
Object newInput) {
//
}
});
treeViewer.setLabelProvider(new LabelProvider() {
public String getText(Object element) {
return ((Category)element).getName();
}
});
treeViewer.setInput(categories);
}
public void show() {
tree.setSize(300, 200);
shell.setSize(300, 200);
shell.open();
// Set up the event loop.
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
// If no more entries in event queue
display.sleep();
}
}
display.dispose();
}
public static void main(String[] args) {
CategoryTree tree = new CategoryTree();
//tree.traditional();
tree.MVC();
tree.show();
}
/**
* Represents a category of items.
* The max level of categories is 2 only.
*
*/
class Category {
private String name;
private Vector subCategories;
private Category parent;
public Category(String name, Category parent) {
this.name = name;
this.parent = parent;
if(parent != null)
parent.addSubCategory(this);
}
public Vector getSubCategories() {
return subCategories;
}
private void addSubCategory(Category subcategory) {
if(subCategories == null)
subCategories = new Vector();
if(! subCategories.contains(subcategory))
subCategories.add(subcategory);
}
public String getName() {
return name;
}
public Category getParent() {
return parent;
}
}
}
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