我想模拟java包浏览器视图，将新项目附加到现有资源管理器视图中。我尝试使用setInput和refresh方法，但它为新输入创建TreeView，旧输入消失了。如何将新输入附加到TreeViewer中的现有元素。有没有办法在inputChanged方法中处理这个问题。
代码段：
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("C:\\Auto"); // pass a non-null that will be ignored
final Action a = new Action("") {
};
final MenuManager mgr = new MenuManager();
mgr.setRemoveAllWhenShown(true);
mgr.addMenuListener(new IMenuListener() {
@Override
public void menuAboutToShow(IMenuManager manager) {
IStructuredSelection selection = (IStructuredSelection) tv
.getSelection();
if (!selection.isEmpty()) {
try {
a.setImageDescriptor(ImageDescriptor
.createFromImage(new Image(null,
new FileInputStream(
"icons/action_refresh.gif"))));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
a.setText("Refresh Action for "
+ (selection.getFirstElement()).toString());
mgr.add(a);
}
}
});
tv.getControl().setMenu(mgr.createContextMenu(tv.getControl()));
tv.addDoubleClickListener(new IDoubleClickListener() {
@Override
public void doubleClick(DoubleClickEvent event) {
TreeViewer viewer = (TreeViewer) event.getViewer();
IStructuredSelection thisSelection = (IStructuredSelection) event
.getSelection();
Object selectedNode = thisSelection.getFirstElement();
System.out.println(selectedNode.toString());
}
});
// 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);
tv.setInput("C:\\Users\\amrit\\GreenLamba");
tv.refresh();
}
});
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
File base = (File) arg0;
Object obj[] = null;
if (base.isFile()) {
if (base.getName().endsWith(".xls")) {
try {
Workbook scriptWorkbook = Workbook.getWorkbook(base);
obj = scriptWorkbook.getSheetNames();
} catch (Exception E) {
}
}
} else {
obj = base.listFiles();
}
return obj;
}
/**
* 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
System.out.println("get elements called " + arg0);
return new File((String) arg0).listFiles();
}
/**
* 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) {
System.out.println("input changed called !!");
System.out.println("input 1" + arg1);
System.out.println("input 1" + arg2);
// Nothing to change
}
}
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("icons/page.gif"));
dir = new Image(null, new FileInputStream("icons/folder.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 = null;
if (arg0 instanceof File) {
text = ((File) arg0).getName();
} else {
text = (String) arg0;
}
// 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);
}
}