Java--图片浏览器

功能：启动后选择打开文件，可以打开图片进行浏览。

v 1.0 ：支持上一张 下一张功能。（欠缺，窗口大小未随着图片大小而改变）

 import java.awt.BorderLayout;
 import java.awt.EventQueue;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.io.File;
 import java.io.IOException;

 import javax.imageio.ImageIO;
 import javax.swing.ImageIcon;
 import javax.swing.JButton;
 import javax.swing.JFileChooser;
 import javax.swing.JFrame;
 import javax.swing.JLabel;
 import javax.swing.JMenu;
 import javax.swing.JMenuBar;
 import javax.swing.JMenuItem;
 import javax.swing.JOptionPane;
 import javax.swing.JToolBar;

 public class TestMenu extends JFrame {
     private JToolBar toolBar = new JToolBar();
     private JButton up = new JButton("up");
     private JButton down = new JButton("down");
     private JLabel label;
     private JFileChooser chooser;
     private static String[] currentPath = new String[10000];// 最多一万张图片
     private static int dirPhotoCount = 0;
     private static boolean flag = false; //user yes or not open dir

     public static void getFileNameToFullPhotoArray(String dirPath) {
         String path = dirPath;
         File f = new File(path);
         if (!f.exists()) {
             System.out.println(path + " not exists");
             return;
         }
         int cut = 0;
         File fa[] = f.listFiles();
         for (int i = 0; i < fa.length; i++) {
             File fs = fa[i];
             try {
                 if (ImageIO.read(fs) != null) { // Yes or not photo style file.
                     currentPath[cut++] = dirPath + "\\" + fs.getName();
                 }
             } catch (IOException ex) {

             }
         }
         dirPhotoCount = cut;
     }

     public TestMenu() {
         super();
         setTitle("PHOTO viewer");
         getContentPane().add(toolBar, BorderLayout.NORTH);
         label = new JLabel();
         this.chooser = new JFileChooser();// java provide file selected
         chooser.setCurrentDirectory(new File("."));// view path

         JMenuBar jmb = new JMenuBar();
         setJMenuBar(jmb);
         JMenu fileMenu = new JMenu("File");
         JMenuItem jmiExit = new JMenuItem("Exit");
         JMenuItem jmiOpen = new JMenuItem("Open");
         jmb.add(fileMenu);
         toolBar.add(up);
         toolBar.add(down);
         getContentPane().add(toolBar, BorderLayout.NORTH);
         add(label);
         jmb.add(fileMenu);
         fileMenu.add(jmiOpen);
         fileMenu.add(jmiExit);

         up.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent e) {

                 if (flag) {
                     String dir = chooser.getSelectedFile().getParent();
                     getFileNameToFullPhotoArray(dir);// current dir build photo array
                     String currentImage = label.getIcon().toString();
                     for (int i = 0; i < dirPhotoCount; i++) {
                         if (currentPath[i].equals(currentImage)) {
                             label.setIcon(new ImageIcon(currentPath[i == 0 ? dirPhotoCount - 1 : i - 1]));
                             break;
                         }
                     }
                 } else {
                     JOptionPane.showMessageDialog(null, "当前无图片，请选择正确文件", "打开失败", JOptionPane.ERROR_MESSAGE);

                 }
             }

         });
         down.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent e) {

                 if (flag) {
                     String dir = chooser.getSelectedFile().getParent();
                     getFileNameToFullPhotoArray(dir);// 对当前目录建立图片数组
                     String currentImage = label.getIcon().toString();
                     for (int i = 0; i < dirPhotoCount; i++) {
                         if (currentPath[i].equals(currentImage)) {
                             label.setIcon(new ImageIcon(currentPath[i == dirPhotoCount - 1 ? 0 : i + 1]));
                             break;
                         }
                     }
                 } else {

                     JOptionPane.showMessageDialog(null, "当前无图片，请选择正确文件", "打开失败", JOptionPane.ERROR_MESSAGE);

                 }
             }

         });

         jmiOpen.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent e) {
                 int result = chooser.showOpenDialog(null);
                 if (result == JFileChooser.APPROVE_OPTION) {
                     try {
                         if (ImageIO.read(chooser.getSelectedFile()) != null) { // 判断是否是图片文件
                             flag = true;
                             String name = chooser.getSelectedFile().getPath();
                             label.setIcon(new ImageIcon(name));
                         } else {
                             JOptionPane.showMessageDialog(null, "请选择正确文件", "打开失败", JOptionPane.ERROR_MESSAGE);
                         }
                     } catch (IOException ex) {

                     }

                 }
             }
         });

         jmiExit.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent e) {
                 System.exit(0);
             }
         });
     }

     public static void main(String args[]) {
         EventQueue.invokeLater(new Runnable() {// using Runnable anonymous
                                                 // object
             public void run() {
                 JFrame frame = new TestMenu();
                 frame.setSize(500, 400);
                 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                 frame.setVisible(true);

             }

         });

     }

 }