该程序运行良好，但我无法看到它是如何链接在一起的。我的意思是，我不调用 Icontent 提供者或 Ilabel 提供者扩展的类中的方法；它是如何被调用的？
我从http://java2s.com/复制了代码。
package com.test;
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;
/**
* This class demonstrates TreeViewer. It shows the drives, directories, and
* files on the system.
*/
public class FileTree extends ApplicationWindow {
/**
* FileTree constructor
*/
public FileTree() {
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);
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);
tv.getTree().setLayoutData(new GridData(GridData.FILL_BOTH));
tv.setContentProvider(new FileTreeContentProvider());
tv.setLabelProvider(new FileTreeLabelProvider());
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 FileTree().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
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
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
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
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 {
file = new Image(null, new FileInputStream("images/file.gif"));
dir = new Image(null, new FileInputStream("images/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.
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.
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
return preserveCase ? text : text.toUpperCase();
}
/**
* Adds a listener to this label provider
*
* @param arg0
* the listener
*/
public void addListener(ILabelProviderListener arg0) {
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) {
listeners.remove(arg0);
}
}