filebrowsertreeviewer.java

用swt实现的treeviewer的程序.是一个文件浏览器.

package com.free.viewer;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.jface.viewers.ILabelProviderListener;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.LabelProviderChangedEvent;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.window.ApplicationWindow;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

/**
 * <p>
 * Title: Eclipse Plugin Development
 * </p>
 * <p>
 * Description: Free download
 * </p>
 * <p>
 * Copyright: Copyright (c) 2006
 * </p>
 * <p>
 * Company: Free
 * </p>
 * 
 * @author gan.shu.man
 * @version 1.0
 */

public class FileBrowserTreeViewer extends ApplicationWindow {
	/**
	 * FileTree constructor
	 */
	public FileBrowserTreeViewer() {
		super(null);
	}

	/**
	 * Runs the application
	 */
	public void run() {
		// Don't return from open() until window closes
		setBlockOnOpen(true);

		// Open the main window
		open();

		// Dispose the display
		Display.getCurrent().dispose();
	}

	/**
	 * Configures the shell*
	 * 
	 * @param shell
	 *            the shell
	 */
	protected void configureShell(Shell shell) {
		super.configureShell(shell);

		// Set the title bar text and the size
		shell.setText("File Tree");
		shell.setSize(400, 400);
	}

	/**
	 * Creates the main window's contents
	 * 
	 * @param parent
	 *            the main window
	 * @return Control
	 */
	protected Control createContents(Composite parent) {
		Composite composite = new Composite(parent, SWT.NONE);
		// 父容器分一列显示
		composite.setLayout(new GridLayout(1, false));

		// Add a checkbox to toggle whether the labels preserve case
		Button preserveCase = new Button(composite, SWT.CHECK);
		preserveCase.setText("&Preserve case");

		// Create the tree viewer to display the file tree
		final TreeViewer tv = new TreeViewer(composite);
		// 让树组件两端对齐
		tv.getTree().setLayoutData(new GridData(GridData.FILL_BOTH));
		// 添加内容管理器
		tv.setContentProvider(new FileTreeContentProvider());
		// 添加标签管理器
		tv.setLabelProvider(new FileTreeLabelProvider());
		// 设置treeviewer的输入
		tv.setInput("root"); // pass a non-null that will be ignored

		// When user checks the checkbox, toggle the preserve case attribute
		// of the label provider
		preserveCase.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent event) {
				boolean preserveCase = ((Button) event.widget).getSelection();
				FileTreeLabelProvider ftlp = (FileTreeLabelProvider) tv
						.getLabelProvider();
				ftlp.setPreserveCase(preserveCase);
				
			}
		});
		return composite;
	}

	/**
	 * The application entry point
	 * 
	 * @param args
	 *            the command line arguments
	 */
	public static void main(String[] args) {
		new FileBrowserTreeViewer().run();
	}
}

/**
 * This class provides the content for the tree in FileTree
 */

class FileTreeContentProvider implements ITreeContentProvider {
	/**
	 * Gets the children of the specified object
	 * 
	 * @param arg0
	 *            the parent object
	 * @return Object[]
	 */
	public Object[] getChildren(Object arg0) {
		// Return the files and subdirectories in this directory
		//返回树的下一级结点
		return ((File) arg0).listFiles();
	}

	/**
	 * Gets the parent of the specified object
	 * 
	 * @param arg0
	 *            the object
	 * @return Object
	 */
	public Object getParent(Object arg0) {
		// Return this file's parent file
		//返回树的上一级结点	
		return ((File) arg0).getParentFile();
	}

	/**
	 * Returns whether the passed object has children
	 * 
	 * @param arg0
	 *            the parent object
	 * @return boolean
	 */
	public boolean hasChildren(Object arg0) {
		// Get the children
		Object[] obj = getChildren(arg0);

		// Return whether the parent has children
		//判断树是否有下一级结节，true为在节点显示"+"信息
		return obj == null ? false : obj.length > 0;
	}

	/**
	 * Gets the root element(s) of the tree
	 * 
	 * @param arg0
	 *            the input data
	 * @return Object[]
	 */
	public Object[] getElements(Object arg0) {
		// These are the root elements of the tree
		// We don't care what arg0 is, because we just want all
		// the root nodes in the file system

		//打印出树的输入信息，通常用户可以通过输入信息构建树
		System.out.println(arg0);
		// File.listRoots()作为树的根结点
		return File.listRoots();
	}

	/**
	 * Disposes any created resources
	 */
	public void dispose() {
		// Nothing to dispose
	}

	/**
	 * Called when the input changes
	 * 
	 * @param arg0
	 *            the viewer
	 * @param arg1
	 *            the old input
	 * @param arg2
	 *            the new input
	 */
	public void inputChanged(Viewer arg0, Object arg1, Object arg2) {
		// Nothing to change
	}
}

/**
 * This class provides the labels for the file tree
 */

class FileTreeLabelProvider implements ILabelProvider {
	// The listeners
	private List listeners;

	// Images for tree nodes
	private Image file;

	private Image dir;

	// Label provider state: preserve case of file names/directories
	boolean preserveCase;

	/**
	 * Constructs a FileTreeLabelProvider
	 */
	public FileTreeLabelProvider() {
		// Create the list to hold the listeners
		listeners = new ArrayList();

		// Create the images
		try {
			//添加文件和目录的图标
			file = new Image(null, new FileInputStream("icons/file.gif"));
			dir = new Image(null, new FileInputStream("icons/directory.gif"));
		} catch (FileNotFoundException e) {
			// Swallow it; we'll do without images
		}
	}

	/**
	 * Sets the preserve case attribute
	 * 
	 * @param preserveCase
	 *            the preserve case attribute
	 */
	public void setPreserveCase(boolean preserveCase) {
		this.preserveCase = preserveCase;

		// Since this attribute affects how the labels are computed,
		// notify all the listeners of the change.
		//触发事件，重新得到显示标签
		LabelProviderChangedEvent event = new LabelProviderChangedEvent(this);
		for (int i = 0, n = listeners.size(); i < n; i++) {
			ILabelProviderListener ilpl = (ILabelProviderListener) listeners
					.get(i);
			ilpl.labelProviderChanged(event);
		}
	}

	/**
	 * Gets the image to display for a node in the tree
	 * 
	 * @param arg0
	 *            the node
	 * @return Image
	 */
	public Image getImage(Object arg0) {
		// If the node represents a directory, return the directory image.
		// Otherwise, return the file image.
		//返回目录或文件的图标
		return ((File) arg0).isDirectory() ? dir : file;
	}

	/**
	 * Gets the text to display for a node in the tree
	 * 
	 * @param arg0
	 *            the node
	 * @return String
	 */
	public String getText(Object arg0) {
		// Get the name of the file
		String text = ((File) arg0).getName();

		// If name is blank, get the path
		if (text.length() == 0) {
			text = ((File) arg0).getPath();
		}

		// Check the case settings before returning the text
		//返回目录或文件的文件名
		return preserveCase ? text : text.toUpperCase();
	}

	/**
	 * Adds a listener to this label provider
	 * 
	 * @param arg0
	 *            the listener
	 */
	public void addListener(ILabelProviderListener arg0) {
		//添加监听器
		listeners.add(arg0);
	}

	/**
	 * Called when this LabelProvider is being disposed
	 */
	public void dispose() {
		// Dispose the images
		if (dir != null)
			dir.dispose();
		if (file != null)
			file.dispose();
	}

	/**
	 * Returns whether changes to the specified property on the specified
	 * element would affect the label for the element
	 * 
	 * @param arg0
	 *            the element
	 * @param arg1
	 *            the property
	 * @return boolean
	 */
	public boolean isLabelProperty(Object arg0, String arg1) {
		return false;
	}

	/**
	 * Removes the listener
	 * 
	 * @param arg0
	 *            the listener to remove
	 */
	public void removeListener(ILabelProviderListener arg0) {
		//删除监听器
		listeners.remove(arg0);
	}
}