Question

我陷入了这个问题：

我有一个JTree可以显示整个目录及其子目录，但是我需要对其进行过滤以仅显示带有某些扩展名（例如“ .m”，“。py”）的目录和文件。

package classes;

import java.io.File;
import java.io.FilenameFilter;
import java.util.Iterator;
import java.util.Vector;
import javax.swing.event.TreeModelEvent;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;

public class FileTree implements TreeModel{
private File root;
private Vector listeners = new Vector();

public FileTree(File rootDirectory){
    root = rootDirectory;
}

@Override
public Object getRoot(){
    return root;
}

@Override
public Object getChild(Object parent, int index){
    File directory = (File) parent;
    String[] children = directory.list(new FilenameFilter(){
        @Override
        public boolean accept(File dir, String name){
            return name.endsWith(".m") || dir.isDirectory();
        }           
    });
    return new FileTree.TreeFile(directory, children[index]);
}

@Override
public int getChildCount(Object parent){
    File file = (File) parent;
    if (file.isDirectory()){
        String[] fileList = file.list();          
        if (fileList != null){
            return file.list().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 directory = (File) parent;
    File file = (File) child;
    String[] children = directory.list();
    for (int i = 0; i < children.length; i++){
        if (file.getName().equals(children[i])){
            return i;
        }
    }
    return -1;
}

@Override
public void valueForPathChanged(TreePath path, Object value){
    File oldFile = (File) path.getLastPathComponent();
    String fileParentPath = oldFile.getParent();
    String newFileName = (String) value;
    File targetFile = new File(fileParentPath, newFileName);
    oldFile.renameTo(targetFile);
    File parent = new File(fileParentPath);
    int[] changedChildrenIndices = {getIndexOfChild(parent, targetFile)};
    Object[] changedChildren = {targetFile};
    fireTreeNodesChanged(path.getParentPath(), changedChildrenIndices, changedChildren);
}

private void fireTreeNodesChanged(TreePath parentPath, int[] indices, Object[] children){
    TreeModelEvent event = new TreeModelEvent(this, parentPath, indices, children);
    Iterator iterator = listeners.iterator();
    TreeModelListener listener = null;
    while (iterator.hasNext()){
        listener = (TreeModelListener) iterator.next();
        listener.treeNodesChanged(event);
    }
}

@Override
public void addTreeModelListener(TreeModelListener listener){
    listeners.add(listener);
}

@Override
public void removeTreeModelListener(TreeModelListener listener){
    listeners.remove(listener);
}

private class TreeFile extends File{

    public TreeFile(File parent, String child){
        super(parent, child);
    }

    @Override
    public String toString(){
        return getName();
    }
  }
}

在我的main()方法中，我将其命名为

JTree tree = new JTree();
tree.setModel(new FileTree(new File("\\C:\\")));
treePanel.setViewportView(tree);

我认为问题出在getChild()方法中，但是我可以弄清楚如何解决。

file.list()和file.listFiles()方法之间是否有区别？因为我已经使用了两者，但仍然不了解。

编辑：遵循@Thomas建议后，现在它向我显示此错误：

PS：当我在getChild()方法上打印“ children”变量以进行调试时，它将返回“ C：\”中的所有目录（共有14个）。

线程“ AWT-EventQueue-0”中的异常java.lang.ArrayIndexOutOfBoundsException：14

更新的方法：

    @Override
public int getIndexOfChild(Object parent, Object child){
    File directory = (File) parent;
    File file = (File) child;
    String[] children = directory.list(new FilenameFilter(){
        @Override
        public boolean accept(File dir, String name){
            return name.endsWith(".m") || new File(dir, name).isDirectory();
        }
    });
    for (int i = 0; i < children.length; i++){
        if (file.getName().equals(children[i])){
            return i;
        }
    }
    return -1;
}

和

    @Override
public int getChildCount(Object parent){
    File file = (File) parent;
    if (file.isDirectory()){
        String[] fileList = file.list(new FilenameFilter(){
            @Override
            public boolean accept(File dir, String name){
                return name.endsWith(".m") || new File(dir, name).isDirectory();
            }
        });          
        if (fileList != null){
            return file.list().length;
        }
    }
    return 0;
}

Answer 1

问题是您对FilenameFilter的实现。

FilenameFilter#accept（https://docs.oracle.com/javase/8/docs/api/java/io/FilenameFilter.html#accept-java.io.File-java.lang.String-）方法的Javadoc描述了参数：

dir-在其中找到文件的目录。
name-文件名。

根据此说明，很明显您的accept方法：

    public boolean accept(File dir, String name){
        return name.endsWith(".m") || dir.isDirectory();
    }

将始终返回true，因为dir始终是目录。

如果要检查目录name中的条目dir是否为目录，则必须将accept方法重写为

    public boolean accept(File dir, String name){
        return name.endsWith(".m") || new File(dir, name).isDirectory();
    }

这只会为您提供名称以“ .m”结尾的目录和文件。

但是现在您还需要更改getChildCount()和getIndexOfChild()方法-因为当前它们基于未过滤的子列表。

JTree不过滤扩展

1 个答案: