JFace TreeViewer简单示例

SWT/JFace控件中最复杂的应该是TreeViewer吧，每次要实现一个TreeViewer都得想半天，这回发现JFace本身包含一个TreeNode(org.eclipse.jface.viewers.TreeNode)和TreeNodeContentProvider(org.eclipse.jface.viewers.TreeNodeContentProvider)的实现，参考写了一个基本通用的示例。

TreeNode:

import java.util.ArrayList;
import java.util.List;

public abstract class TreeNode {
protected TreeNode parent;
protected List children = new ArrayList();

public abstract String getName();

public abstract void setName(String name);

public TreeNode getParent() {
return parent;
}

public void setParent(TreeNode parent) {
this.parent = parent;
}

public TreeNode[] getChildren() {
return (TreeNode[]) children.toArray(new TreeNode[children.size()]);
}

public void setChildren(List children) {
this.children = children;
}

public boolean hasChildren(){
return this.children.size() > 0;
}

public void addChild(TreeNode child){
this.children.add(child);
}

public void removeChild(TreeNode child){
this.children.remove(child);
child.setParent(null);
}

public void addChild(int index, TreeNode child){
this.children.add(index, child);
}

public void setChild(int index, TreeNode child){
this.children.set(index, child);
}

public void removeChild(int index){
this.children.remove(index);
}

public void removeAllChildren() {
this.children.clear();
}

public String toString(){
return getName();
}

}

TreeContentProvider:

import org.eclipse.jface.viewers.TreeNodeContentProvider;
import org.eclipse.jface.viewers.Viewer;

public class TreeContentProvider extends TreeNodeContentProvider{
@Override
public Object[] getChildren(Object element) {
if(element != null) {
if(element instanceof TreeNode){
return ((TreeNode)element).getChildren();
}
return new Object[0];
}
return new Object[0];
}

@Override
public Object getParent(Object element) {
if(element != null) {
if(element instanceof TreeNode){
return ((TreeNode)element).getParent();
}
return null;
}
return null;
}

@Override
public Object[] getElements(Object inputElement) {
if(inputElement instanceof TreeNode[]){
return (TreeNode[])inputElement;
}
return new Object[0];
}

@Override
public boolean hasChildren(Object element) {
if(element != null) {
if(element instanceof TreeNode){
return ((TreeNode)element).hasChildren();
}
return false;
}
return false;
}

@Override
public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
//TODO
}
}

TreeLabelProvider

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.swt.graphics.Image;

public class TreeLabelProvider extends LabelProvider {
private Map imageCache = new HashMap(10);

@Override
public String getText(Object element) {
if(element != null) {
if(element instanceof TreeNode) {
return ((TreeNode)element).getName();
}
else {
return "";
}
}
return "";
}

@Override
public Image getImage (Object element) {
if (element != null) {
ImageDescriptor descriptor = null;
if (element instanceof TreeNode) {
if (element instanceof TreeNode) {
descriptor = Activator.imageDescriptorFromPlugin (Activator.PLUGIN_ID , "icons/node.png");
}

Image image = (Image)imageCache.get(descriptor);
if(image == null) {
image = descriptor.createImage();
imageCache.put(descriptor, image);
}
return image;
}
else {
return null;
}
}
return null;
}

@Override
public void dispose() {
for(Iterator i = imageCache.values().iterator(); i.hasNext();) {
((Image)i.next()).dispose();
}
imageCache.clear();
}
}

复制去Google翻译翻译结果
org.eclipse.jface.viewers.TreeNode