folderexplorer.java

图像管理 对图片进行预览的功能（参考ACDSee界面）。要求在界面中显示一个本地计算机中的文件夹的树形结构

package javaapplication3;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;

   public class FolderExplorer extends JFrame{
     JTree  tree;
     DefaultTreeModel treeModel;
     JLabel lbStatus =new JLabel();
     static String dizhi ;
     String [] changdizhi ;

      
   
     
     public FolderExplorer( ) {
      try{  jbIint();
      }catch (Exception e){e.printStackTrace();}     
    }
   
    void jbIint( )throws Exception{
    initTree();

}
          
    void initTree(){
    DefaultMutableTreeNode top = new DefaultMutableTreeNode( "我的电脑");
    DefaultMutableTreeNode node;
    File[] roots = File.listRoots();
    for (int k=0; k<roots.length; k++)
    {
      node = new DefaultMutableTreeNode( new FileNode(roots[k]));
      top.add(node);
      node.add( new DefaultMutableTreeNode(new String("Retrieving data")));
  }
  treeModel = new DefaultTreeModel(top);
  tree = new JTree(treeModel);
  tree.putClientProperty("JTree.lineStyle", "Angled");
  tree.addTreeExpansionListener(new MyExpansionListener());
  tree.addTreeSelectionListener(new MySelectionListener());
  tree.getSelectionModel().setSelectionMode( TreeSelectionModel.SINGLE_TREE_SELECTION); 
  tree.setShowsRootHandles(true); 
  tree.setEditable(false);
    
    }


DefaultMutableTreeNode getTreeNode(TreePath path)
   {
       return (DefaultMutableTreeNode)(path.getLastPathComponent());
   }

FileNode getFileNode(DefaultMutableTreeNode node)
 {
  if (node == null)
   return null;
  Object obj = node.getUserObject();
  if (obj instanceof FileNode)
   return (FileNode)obj;
  else
   return null;
 }
class MyExpansionListener implements TreeExpansionListener
    {
        public void treeExpanded(TreeExpansionEvent event)
        {
             final DefaultMutableTreeNode node = getTreeNode(
                event.getPath());
             final FileNode fnode = getFileNode(node);

            Thread runner = new Thread() 
            {
              public void run() 
              {
                if (fnode != null && fnode.expand(node)) 
                {
                  Runnable runnable = new Runnable() 
                  {
                    public void run() 
                    {
                       treeModel.reload(node);
                    }
                  };
                  SwingUtilities.invokeLater(runnable);
                }
              }
            };
            runner.start();
        }

        public void treeCollapsed(TreeExpansionEvent event) { }
    }

class MySelectionListener implements TreeSelectionListener 
 {
       // private String imagename;
     //    String[] fileNames;
       
        int i;
        private String[] fileNames;
  public void valueChanged(TreeSelectionEvent event)
  {
      int j=0;
    NewJFrame1.jPanel1.removeAll();
   DefaultMutableTreeNode node = getTreeNode(event.getPath());
   FileNode fileNode = getFileNode(node);
   if (fileNode != null){
    lbStatus.setText(fileNode.getFile().getAbsolutePath());
    dizhi=fileNode.getFile().getAbsolutePath();   
                File onefile = new File(dizhi);
                File dir = new File(dizhi);
    	         fileNames =dir.list();
    	        for(int z=0;z<fileNames.length;z++)
              {
                    if(fileNames[z].endsWith("jpg")||fileNames[z].endsWith("gif")||fileNames[z].endsWith("png"))
                    { 
                      j++;
                    }
                }
                String [] changdizhi=new String[j];
                String [] fileN=new String[j];
               
                for(int i = 0,k=0;i<fileNames.length;i++){
                      if(fileNames[i].endsWith("jpg")||fileNames[i].endsWith("gif")||fileNames[i].endsWith("png"))
                    { //System.out.println(fileNames[i]);
                      changdizhi[k]=dizhi+"\\"+ fileNames[i];
                      k++;
                    }
                }
               
               for(int i = 0,k=0;i<fileNames.length;i++){
                      if(fileNames[i].endsWith("jpg")||fileNames[i].endsWith("gif")||fileNames[i].endsWith("png"))
                    { 
                      fileN[k]= fileNames[i];
                      k++;
                    }
                }
//                int x=0;
//                for(x=0;x<changdizhi.length;x++)
//                  if(!changdizhi[x].equals(" "))   
//            { System.out.println(changdizhi[x]);}
//             fname=fileNames[j];
               new DisplayImage(changdizhi,fileN);
                
    }
   
   else
    lbStatus.setText(" ");
  }

 }

public String getdizhi(){
    return dizhi;
}


public class FileNode
{

 protected File file;

 public FileNode(File file)
 {
  this.file = file;
 }

 public File getFile() 
 { 

     return file;
 }

 public String toString() 
 { 
  return file.getName().length() > 0 ? file.getName() : file.getPath();
 }

 public boolean expand(DefaultMutableTreeNode parent)
 {
  DefaultMutableTreeNode child = (DefaultMutableTreeNode)parent.getFirstChild();
  if (child==null)   // No flag
   return false;
  Object obj = child.getUserObject();
  if (!(obj instanceof String))
   return false;      // Already expanded

  parent.removeAllChildren();  // Remove Flag

  File[] files = listFiles();
  if (files == null)
   return true;

  Vector v = new Vector();

  for (int k=0; k<files.length; k++)
  {
   File f = files[k];
   if (!(f.isDirectory()))
    continue;

   FileNode newNode = new FileNode(f);
   boolean isAdded = false;
   for (int j=0; j<v.size(); j++)
   {
    FileNode node = (FileNode)v.elementAt(j);
    if (newNode.compareTo(node) < 0)
    {
     v.insertElementAt(newNode, j);
     isAdded = true;
     break;
    }
   }
   if (!isAdded)
    v.addElement(newNode);
  }

  for (int i=0; i<v.size(); i++)
  {
   FileNode fileNode = (FileNode)v.elementAt(i);
 //  IconData idata = new IconData(FileTree1.ICON_FOLDER,  FileTree1.ICON_EXPANDEDFOLDER, fileNode);
   DefaultMutableTreeNode node = new DefaultMutableTreeNode(fileNode);
   parent.add(node);  
   if (fileNode.hasSubDirs())
    node.add(new DefaultMutableTreeNode( new String("Retriveving data") ));
  }

  return true;
 }

 public boolean hasSubDirs()
 {
  File[] files = listFiles();
  if (files == null)
   return false;
  for (int k=0; k<files.length; k++)
  {
   if (files[k].isDirectory())
    return true;
  }
  return false;
 }
 
 public int compareTo(FileNode toCompare)
 { 
  return  file.getName().compareToIgnoreCase(toCompare.file.getName() ); 
 }

 protected File[] listFiles()
 {
  if (!file.isDirectory())
   return null;
  try
  {
   return file.listFiles();
  }
  catch (Exception ex)
  {
   JOptionPane.showMessageDialog(null, 
    "Error reading directory "+file.getAbsolutePath(),
    "Warning", JOptionPane.WARNING_MESSAGE);
   return null;
  }
 }
    }




}