frameofpicviewer.java

Java实例入门

package picviewer;

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

/**
 * Title:        图片浏览器
 * Description:  这是一个用于浏览磁盘上图片文件的程序
 * Copyright:    Copyright (c) 2001
 * Company:
 * @author java_user
 * @version 1.0
 */

public class FrameOfPicViewer extends JFrame {
  BorderLayout borderLayout1 = new BorderLayout();
  JLabel StatusBar = new JLabel();
  JPanel mainPanel = new JPanel();
  GridLayout gridLayout1 = new GridLayout();
  JPanel leftPanel = new JPanel();
  JPanel rightPanel = new JPanel();
  BorderLayout borderLayout2 = new BorderLayout();
  JComboBox cmbDrivers = new JComboBox();
  JLabel jLabel1 = new JLabel();
  JScrollPane jScrollPane1 = new JScrollPane();
  JTree treFileList;
  TreeNode root;
  DefaultTreeModel model;
  String selDriver="";
  String selFilePath="";
  boolean runState=false;
  boolean selState=false;

  public FrameOfPicViewer() {
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
    runState=true;
  }
  public static void main(String[] args) {
    try {
         UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    }
    catch(Exception e) {
    }

    FrameOfPicViewer frameOfPicViewer = new FrameOfPicViewer();
  }
  private void jbInit() throws Exception {
    this.getContentPane().setLayout(borderLayout1);
    StatusBar.setText("   ");
    mainPanel.setLayout(gridLayout1);
    gridLayout1.setColumns(2);
    leftPanel.setLayout(borderLayout2);
    jLabel1.setText("请选择图片文件");
    this.setTitle("图片浏览器");
    this.addWindowListener(new java.awt.event.WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        this_windowClosing(e);
      }
    });
    cmbDrivers.addItemListener(new java.awt.event.ItemListener() {
      public void itemStateChanged(ItemEvent e) {
        cmbDrivers_itemStateChanged(e);
      }
    });
    this.getContentPane().add(StatusBar, BorderLayout.SOUTH);
    this.getContentPane().add(mainPanel, BorderLayout.CENTER);
    mainPanel.add(leftPanel, null);
    mainPanel.add(rightPanel, null);
    leftPanel.add(cmbDrivers,  BorderLayout.NORTH);
    leftPanel.add(jScrollPane1, BorderLayout.CENTER);
    this.getContentPane().add(jLabel1, BorderLayout.NORTH);
    loadDrivers(cmbDrivers);
    selDriver=cmbDrivers.getSelectedItem().toString().trim();
    root=loadFilePaths(selDriver);
    model=new DefaultTreeModel(root);
    treFileList=new JTree(model);
    jScrollPane1.getViewport().add(treFileList, null);
    DefaultTreeCellRenderer render=new DefaultTreeCellRenderer();
    render.setClosedIcon(new ImageIcon("images/closed.gif"));
    render.setOpenIcon(new ImageIcon("images/open.gif"));
    render.setLeafIcon(new ImageIcon("images/leaf.gif"));
    treFileList.setCellRenderer(render);
   // treFileList.setEditable(true);
    int selModel=TreeSelectionModel.SINGLE_TREE_SELECTION ;
    treFileList.getSelectionModel().setSelectionMode(selModel);
    treFileList.addTreeSelectionListener(new javax.swing.event.TreeSelectionListener() {
      public void valueChanged(TreeSelectionEvent e) {
        treFileList_valueChanged(e);
      }
    });
    setSize(600,300);
    selState=true;
    show();
  }

  void this_windowClosing(WindowEvent e) {
    System.exit(0);
  }
  private void loadDrivers(JComboBox cmbBox){
    //建立当前路径的File对象
    File currentPath=new File(".");
    File[] drivers=currentPath.listRoots();
    //得到计算机中所有驱动器的名称
    for(int i=0;i<= drivers.length -1;i++){
       cmbBox.addItem(drivers[i].toString());
    }
    //缺省值设置为当前路径的驱动器
    String path=currentPath.getAbsolutePath();
    for(int i=0;i<= drivers.length -1;i++){
      if(path.indexOf(cmbBox.getItemAt(i).toString().trim() )>=0) {
          cmbBox.setSelectedItem(cmbBox.getItemAt(i));
         break;
      }
    }
  }
  //利用递归函数得到选择驱动器中所有的图片文件
  private TreeNode  loadFilePaths(String rootPath){
    StatusBar.setText("  ");
    File path=new File(rootPath);
    DefaultMutableTreeNode root=new DefaultMutableTreeNode(path.getName().trim());
    DefaultTreeModel model=new DefaultTreeModel(root);
    File[] childsOfPath=path.listFiles();
    for(int i=0;i<=childsOfPath.length-1;i++){
        String name=childsOfPath[i].getName().trim();
       if(childsOfPath[i].isDirectory() ){
          DefaultMutableTreeNode childRoot;
          childRoot=(DefaultMutableTreeNode)loadFilePaths(childsOfPath[i].getAbsolutePath());
         if(childRoot.getChildCount() >0)
            root.add(childRoot);
        }
       else {
          int  c=name.lastIndexOf(".")  ;
           String fileType=name.substring(c+1).toUpperCase();
          if(fileType.equals("JPG") ||fileType.equals("GIF") ){
               DefaultMutableTreeNode childRoot=new DefaultMutableTreeNode(name);
               root.add(childRoot);
           }
        }
    }

    return root;

  }

  void cmbDrivers_itemStateChanged(ItemEvent e) {
     selState=false;
     String strDriver=cmbDrivers.getSelectedItem().toString().trim();
     if(runState&& !strDriver.equals(selDriver))  {
          DefaultMutableTreeNode newRoot=(DefaultMutableTreeNode)loadFilePaths(strDriver);
          Enumeration childs=((DefaultMutableTreeNode)root).children();
         while(childs.hasMoreElements() ){
             DefaultMutableTreeNode node= (DefaultMutableTreeNode)childs.nextElement();
             model.removeNodeFromParent(node  );
          }
         for(int i=1;i<=newRoot.getChildCount() ;i++){
             model.insertNodeInto((DefaultMutableTreeNode)newRoot.getChildAt(i-1),(DefaultMutableTreeNode)root,0 );
         }
          model.reload(root);
          selDriver=strDriver;
     }
     selState=true;
  }

  void treFileList_valueChanged(TreeSelectionEvent e) {
     if(selState){
        TreePath path=treFileList.getSelectionPath();
        DefaultMutableTreeNode node=(DefaultMutableTreeNode)path.getLastPathComponent();
       if(node.isLeaf() ){
            String selFile="";
            String strPath=path.toString();
            strPath=strPath.replace('[',' ');
            strPath=strPath.replace(']',' ').trim();
           for(int i=1;i<=path.getPathCount()-1;i++ ){
               int c=strPath.lastIndexOf(",") ;
                selFile=strPath.substring(c+1).trim()+"\\"+selFile;
                strPath=strPath.substring(0,c);
            }
            selFile=selDriver+selFile.substring(0,selFile.length()-1).trim();
            loadPic(selFile);
       }
   }
  }
  void loadPic(String picName){
     ImageIcon img=new ImageIcon(picName);
     int pWidth=rightPanel.getWidth();
     int pHeight=rightPanel.getHeight();
     int mWidth=img.getIconWidth() ;
     int mHeight=img.getIconHeight() ;
     int x,y;
     int width,height;
     if((mWidth<=pWidth)&&(mHeight<=pHeight)){
        x=(pWidth-mWidth)/2;    y=(pHeight-mHeight)/2;
        width=mWidth;   height=mHeight;
     }else {
        width=pWidth;   height=pHeight;
       float widthScale=(float)pWidth/(float)mWidth;
       float heightScale=(float)pHeight/(float)mHeight;
       if(widthScale<heightScale)
           height=(int)(mHeight*widthScale);
       else
           width=(int)(mWidth*heightScale);
        x=(pWidth-width)/2;
        y=(pHeight-height)/2;
     }
     StatusBar.setText("文件:"+picName+"    大小:"+mWidth+"X"+mHeight);
     rightPanel.getGraphics().clearRect(0,0,pWidth,pHeight);
     rightPanel.getGraphics().drawImage(img.getImage(),x,y,width,height,this);
  }
}