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在我的项目的GUI中，我使用JTree来显示一个文件系统，我遇到了一个渲染特定的问题：看起来JTree中的一些条目能够正确呈现以及呈现它们自己先前选择的条目。这很难解释，所以我认为包括截图将是最容易理解的。JTree入口呈现问题
要做到这一点，我迅速移动从上到下使用箭头键。
我不完全知道这个问题的根源，但我怀疑这可能是我的TreeModel或CellRenderer，这两个都包括在下面的问题。
任何帮助，可以帮助我解决这个问题是值得欢迎的！
import java.awt.Component;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Vector;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.WindowConstants;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;
public class MCVE {
public static void main(String[] args) throws Throwable {
JFrame frame = new JFrame();
frame.getContentPane().add(new FileSystemTree(new File(System.getProperty("user.home"))));
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}
class FileSystemTree extends JPanel {
private File root;
private FileSystemTreeModel model;
private final JTree fileSystem;
public FileSystemTree(File root) throws IOException {
this.root = root;
model = new FileSystemTreeModel(root);
fileSystem = new JTree(model);
fileSystem.setEditable(false);
fileSystem.setCellRenderer(new FileSystemTreeCellRenderer());
fileSystem.putClientProperty("JTree.lineStyle", "None");
add(new JScrollPane(fileSystem));
}
}
class FileSystemTreeCellRenderer extends DefaultTreeCellRenderer {
private final Icon folderSpecial;
private final Icon folderOther;
private final Icon fileSpecial;
private final Icon fileOther;
public FileSystemTreeCellRenderer() throws IOException {
InputStream stream;
BufferedImage image;
stream = new FileInputStream("folder-special.png");
image = ImageIO.read(stream);
folderSpecial = new ImageIcon(image);
stream.close();
stream = new FileInputStream("folder-other.png");
image = ImageIO.read(stream);
folderOther = new ImageIcon(image);
stream.close();
stream = new FileInputStream("file-special.png");
image = ImageIO.read(stream);
fileSpecial = new ImageIcon(image);
stream.close();
stream = new FileInputStream("file-other.png");
image = ImageIO.read(stream);
fileOther = new ImageIcon(image);
stream.close();
}
@Override
public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus) {
super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
if (value instanceof File) {
Icon icon = null;
File file = (File) value;
if (file.isDirectory()) {
if (file.getName().endsWith("-special")) {
icon = folderSpecial;
} else {
icon = folderOther;
}
} else if (file.isFile()) {
if (file.getName().endsWith(".special")) {
icon = fileSpecial;
} else {
icon = fileOther;
}
}
setIcon(icon);
}
return this;
}
}
class FileSystemTreeModel implements TreeModel, Comparator<File> {
private final File root;
private final Vector<TreeModelListener> listeners = new Vector<>();
public FileSystemTreeModel(File root) {
if (!root.isDirectory()) throw new IllegalArgumentException();
this.root = root;
}
@Override
public int compare(File a, File b) {
if (a.isDirectory() && !b.isDirectory()) return -1;
if (!a.isDirectory() && b.isDirectory()) return 1;
return a.getName().compareToIgnoreCase(b.getName());
}
@Override
public File getRoot() {
return root;
}
@Override
public File getChild(Object parent, int index) {
File dir = (File) parent;
File[] files = dir.listFiles();
String[] children = new String[files.length];
Arrays.sort(files, this::compare);
for (int i = 0; i < files.length; i++) {
children[i] = files[i].getName();
}
return new TreeFile(dir, children[index]);
}
@Override
public int getChildCount(Object parent) {
File file = (File) parent;
if (file.isDirectory()) {
String[] fileList = file.list();
if (fileList != null) return fileList.length;
}
return 0;
}
@Override
public boolean isLeaf(Object node) {
File file = (File) node;
return file.isFile();
}
@Override
public int getIndexOfChild(Object parent, Object child) {
File dir = (File) parent;
File file = (File) child;
File[] children = dir.listFiles();
Arrays.sort(children, this::compare);
for (int i = 0; i < children.length; i++) {
if (file.equals(children[i])) return i;
}
return -1;
}
@Override
public void valueForPathChanged(TreePath path, Object value) {}
@Override
public void addTreeModelListener(TreeModelListener listener) {
listeners.add(listener);
}
@Override
public void removeTreeModelListener(TreeModelListener listener) {
listeners.remove(listener);
}
private static class TreeFile extends File {
public TreeFile(File parent, String path) {
super(parent, path);
}
@Override
public String toString() {
return getName();
}
}
}
1）为了更好地提供帮助，请发布[MCVE]或[简短，独立，正确的示例]（http://www.sscce.org/）。 2）[文件浏览器GUI]（http://codereview.stackexchange.com/q/4446/7784）是否显示类似的工件？ *“（代码）这两个可用”*我（和大多数人）不会跟随代码的链接。制作一个MCVE，在问题中发布。 （投票结束。） –
@AndrewThompson我只是认为添加一个代码链接，而不是让这个问题不合理地长，会使它更容易阅读。而且，因为我不明白这个问题的本质，我认为创建一个MCVE可能会相当困难。但是，哦，我想我会创建一个。可能需要一段时间，直到我更新问题，但是，因为我很快会开会。 – mezzodrinker
我添加了一个演示我的问题的MCVE。 CC @AndrewThompson – mezzodrinker