迭代文件和目录以加载SWT树
我制作了一个Tree对象，它载有来自目录的文件。 preVisistDirectory迭代速度更快，然后visitFile可以跟随填充树。 我尝试构建一个变量，在读取文件后调用它，并创建treeitem以读取下一个目录但不起作用。 任何人??
public static void main(String[] args) {
// getfiles(filepath,"*html");
System.out.println("Help -> setHelp() -> Path = " + filepath);
Display display = new Display();
Shell shell = new Shell(display, SWT.CLOSE | SWT.RESIZE);
shell.setText("Tree Object. ");
shell.setSize(400, 300);
final Tree tree = new Tree(shell, SWT.BORDER | SWT.SINGLE);
tree.setSize(290, 290);
try {
Files.walkFileTree(filepath, new SimpleFileVisitor<Path>() {
TreeItem parent, child;
int baselevel = filepath.getNameCount();
public FileVisitResult preVisitDirectory(Path dir,
BasicFileAttributes attrs) {
System.out.println("Help -> FileVisitResults -> DirectoryName = " + dir.getFileName().toString());
System.out.println("Help -> FileVisitResults -> Find files and Directories : " + dir.getName(0));
System.out.println("Help -> FileVisitResults -> nameCount : " + (dir.getNameCount() - baselevel));
System.out.println("Help -> FileVisitResults -> baselevel = : " + (dir.getNameCount() - baselevel));
if (dir.getNameCount() - baselevel + 1 > 1) {
if (dir.getNameCount() - baselevel == 1) {
parent = null;
}
if (parent != null) {
child = new TreeItem(parent, 0);
child.setText(dir.getFileName().toString());
parent = child;
}
if (parent == null) {
child = new TreeItem(tree, 0);
child.setText(dir.getFileName().toString());
parent = child;
}
}
return FileVisitResult.CONTINUE;
}
public FileVisitResult visitFile(Path dir,
BasicFileAttributes attrs) {
System.out.println("Help -> FileVisitResults -> FileName = " + dir);
if (dir.getNameCount() - baselevel + 1 > 1) {
if (dir.getNameCount() - baselevel == 1) {
parent = null;
}
if (parent != null) {
child = new TreeItem(parent, 0);
child.setText(dir.getFileName().toString());
}
if (parent == null) {
child = new TreeItem(tree, 0);
child.setText(dir.getFileName().toString());
}
}
return FileVisitResult.CONTINUE;
}
});
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
======答案： 没有例外，但通过目录循环更快，然后可以将文件添加到目录中。因此，当2个文件之后vistitFile添加5个文件时，preDirectoryVisit会将父文件设置为下一个目录，因此visitFile会跳过其余文件。
===========答案2 树使用preVisitDirectory方法加载目录，更快地遍历目录，然后visitFile迭代文件。因为找到的目录存储在父变量中，所以使用父树节来将文件添加为子树项目。
2 个答案:
答案 0 :(得分：2)
parent和child节点的概念并没有真正解决。我设法使用两个HashMap来完成它。一个用于目录，一个用于文件。这样，您可以轻松找到当前文件/目录的parent：
private static Map<String, TreeItem> nodes = new HashMap<>();
private static Map<TreeItem, List<String>> children = new HashMap<>();
public static void main(String[] args) {
final Display display = new Display();
final Shell shell = new Shell(display);
shell.setLayout(new FillLayout());
final Tree tree = new Tree(shell, SWT.BORDER);
Path path = FileSystems.getDefault().getPath("/home/baz/TestFolder/", new String[] {});
try {
Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
{
TreeItem parent = nodes.get(dir.getParent().toString());
TreeItem item = null;
if(parent == null)
{
item = new TreeItem(tree, SWT.NONE);
}
else
{
item = new TreeItem(parent, SWT.NONE);
}
item.setText(dir.getFileName().toString());
nodes.put(dir.toString(), item);
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFile(Path dir, BasicFileAttributes attrs)
{
TreeItem parent = nodes.get(dir.getParent().toString());
if(children.get(parent) == null)
children.put(parent, new ArrayList<String>());
children.get(parent).add(dir.getFileName().toString());
return FileVisitResult.CONTINUE;
}
});
} catch (IOException e) {
e.printStackTrace();
}
for(TreeItem parent : children.keySet())
{
for(String child : children.get(parent))
{
TreeItem item = new TreeItem(parent, SWT.NONE);
item.setText(child);
}
}
tree.layout();
nodes = null;
children = null;
shell.setSize(400,400);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
正如您可以阅读here一样，遍历的顺序不能保证与文件管理器中的顺序相同。这就是我在将目录的子项添加到树之前收集目录的子项的原因。不需要对目录进行排序。
首先深入了解文件树，但是您不能对访问子目录的迭代顺序做出任何假设。
以下是树的外观：
这是文件夹结构：
答案 1 :(得分：0)
通过在创建树项时向树项添加数据来完成代码。 在树中单击时，数据用于在浏览器面板中打开文件。
package object;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.eclipse.swt.SWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;
public class Helpsystem {
private static Tree tree;
private static Browser browser;
private static Map<String, TreeItem> nodes = new HashMap<>();
private static Map<TreeItem, List<Path>> children = new HashMap<>();
private static String lang="gb";
private static GridData griddatatree,griddatabrowser,griddatatoolbar;
static Path path = FileSystems.getDefault().getPath("html/Help/"+lang+"/",new String[] {});
public static void main(String[] args) {
final Display display = new Display();
final Shell shell = new Shell(display);
GridLayout gridlayout = new GridLayout(5,true);
shell.setLayout(gridlayout);
ToolBar toolbar = new ToolBar(shell, SWT.BORDER);
toolbar.setSize(200, 30);
griddatatoolbar = new GridData(SWT.FILL,SWT.FILL,true,false);
griddatatoolbar.horizontalSpan=5;
toolbar.setLayoutData(griddatatoolbar);
ToolItem home = new ToolItem(toolbar,SWT.PUSH);
home.setText("Home.");
home.setToolTipText("Return to index.");
home.addSelectionListener(new SelectionAdapter(){
public void widgetSelected(SelectionEvent e){
browser.setText("loadPage(indexUrl.toURL())");
}});
ToolItem back = new ToolItem(toolbar,SWT.PUSH);
back.setText("Back.");
back.setEnabled(true);
back.setToolTipText("Previous page.");
back.addSelectionListener(new SelectionAdapter(){
public void widgetSelected(SelectionEvent e){
browser.back();
}});
tree = new Tree(shell, SWT.BORDER);
griddatatree = new GridData(SWT.FILL,SWT.FILL,true,true);
griddatatree.horizontalSpan=2;
tree.setLayoutData(griddatatree);
tree.addListener(SWT.Selection,new Listener(){
public void handleEvent(Event e){
for(TreeItem selection:tree.getSelection()){
if(selection.getData()==null){return;};
try {
URL url= ((URI) selection.getData()).toURL();
browser.setText(loadPage(url));
} catch (MalformedURLException e1) { e1.printStackTrace(); }
}
}
});
browser = new Browser(shell, 0 );
griddatabrowser = new GridData(SWT.FILL,SWT.FILL,true,true);
griddatabrowser.horizontalSpan=3;
browser.setLayoutData(griddatabrowser);
try {
Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
{
TreeItem parent = nodes.get(dir.getParent().toString());
TreeItem item = null;
if(parent == null)
{
item = new TreeItem(tree, SWT.NONE);
}
else
{
item = new TreeItem(parent, SWT.NONE);
}
item.setText(dir.getFileName().toString());
nodes.put(dir.toString(), item);
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFile(Path dir, BasicFileAttributes attrs)
{
TreeItem parent = nodes.get(dir.getParent().toString());
if(children.get(parent) == null)
children.put(parent, new ArrayList<Path>());
children.get(parent).add(dir);
return FileVisitResult.CONTINUE;
}
});
} catch (IOException e) {
e.printStackTrace();
}
for(TreeItem parent : children.keySet())
{
for(Path child : children.get(parent))
{
TreeItem item = new TreeItem(parent, SWT.NONE);
item.setText(child.getFileName().toString());
item.setData(child.toUri());
}
}
nodes = null;
children = null;
shell.setSize(800,600);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
protected static String loadPage(URL helppageUrl) {
String str = null;
try {
InputStream is = helppageUrl.openStream();
InputStreamReader r = new InputStreamReader(is);
char[] buffer = new char[32];
StringBuffer sb = new StringBuffer();
int count;
while ((count = r.read(buffer, 0, buffer.length)) > -1) {
sb.append(buffer, 0, count);
}
str = sb.toString();
is.close();
r.close();
} catch (IOException ex) {
str = "Failed to load text";
}
return str;
}
}
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