程序运行结果：
工程结构图：
程序代码：
import java.awt.BorderLayout;import java.awt.FileDialog;import java.awt.Graphics;import java.awt.Image;import java.awt.Toolkit;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.KeyEvent;import java.awt.event.KeyListener;import java.awt.event.MouseEvent;import java.awt.event.MouseListener;import java.io.File;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import javax.swing.ImageIcon;import javax.swing.JButton;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.JPanel;import javax.swing.JPopupMenu;public class PictureViewer extends JFrame implements ActionListener,KeyListener { /** * author Silocean */ private static final long serialVersionUID = 7249010546054183791L; // 菜单栏 JMenuBar mb = new JMenuBar(); // 文件菜单 JMenu fileMenu = new JMenu("文件"); // 打开文件菜单项 JMenuItem openMenuItem = new JMenuItem("打开"); // 退出程序菜单项 JMenuItem exitMenuItem = new JMenuItem("退出"); // 关于菜单 JMenu aboutMenu = new JMenu("关于"); // 关于菜单项 JMenuItem aboutMenuItem = new JMenuItem("^(oo)^"); // 上一张图片按钮 JButton bLast = new JButton("上一张"); // 图片数量标签 JLabel lCount = new JLabel(); // 下一张图片按钮 JButton bNext = new JButton("下一张"); // 显示图片的主面板 MyPanel mp = new MyPanel(); // 底部面板 JPanel pSouth = new JPanel(); // 右键菜单 JPopupMenu pm = new JPopupMenu(); // 删除图片菜单项 JMenuItem deleteMenuItem = new JMenuItem("删除"); // 图片属性菜单项 JMenuItem propertyMenuItem = new JMenuItem("属性"); // 文件对话框 FileDialog dialog = new FileDialog(this, "打开文件", FileDialog.LOAD); // 默认工具包 Toolkit tk = Toolkit.getDefaultToolkit(); // 要显示的图片 Image img = null; // 用于保存文件夹中所有图片 File[] files = null; // 图片路径 String fileDir = null; // 当前图片位置 int indexOfNow = 0; // 存放图片格式个集合 List<String> imgPatternList = new ArrayList<String>(); // 存放图片路径的集合 List<String> imgList = new ArrayList<String>(); // 当前文件夹中所有图片的数量 int amount = 0; // 自身的一个引用变量 static PictureViewer pv = null; /* * 构造方法初始化窗体 */ public PictureViewer() { this.setJMenuBar(mb); mb.add(fileMenu); fileMenu.add(openMenuItem); fileMenu.add(exitMenuItem); mb.add(aboutMenu); aboutMenu.add(aboutMenuItem); this.add(mp, BorderLayout.CENTER); this.add(pSouth, BorderLayout.SOUTH); lCount.setText("共" + amount + "张" + "，当前第" + indexOfNow + "张"); pSouth.add(bLast); pSouth.add(lCount); pSouth.add(bNext); pm.add(deleteMenuItem); pm.add(propertyMenuItem); openMenuItem.addActionListener(this); exitMenuItem.addActionListener(this); aboutMenuItem.addActionListener(this); bLast.addActionListener(this); bNext.addActionListener(this); bLast.addKeyListener(this); bNext.addKeyListener(this); deleteMenuItem.addActionListener(this); propertyMenuItem.addActionListener(this); imgPatternList.add("JPG"); imgPatternList.add("PNG"); imgPatternList.add("GIF"); /*imgPatternList.add("ICO"); imgPatternList.add("BMP"); imgPatternList.add("TIF"); imgPatternList.add("PCX"); imgPatternList.add("TGA");*/ this.setSize(1000, 650); this.setTitle("照片查看器"); this.setIconImage(tk.getImage(PictureViewer.class.getClassLoader().getResource("icon.png"))); this.setLocationRelativeTo(null); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setVisible(true); } @Override public void actionPerformed(ActionEvent e) { if(e.getSource() == openMenuItem) { // 打开文件 this.openFile(); } else if(e.getSource() == exitMenuItem) { // 退出程序 this.exit(); } else if(e.getSource() == aboutMenuItem) { // 显示关于程序对话框 this.showAboutDialog(); } else if(e.getSource() == bLast) { // 显示上一张图片 this.lastImg(); } else if(e.getSource() == bNext) { // 显示下一张图片 this.nextImg(); } else if(e.getSource() == deleteMenuItem) { // 删除图片 this.deleteImg(); } else if(e.getSource() == propertyMenuItem) { // 显示图片属性对话框 this.showPropertyDialog(); } } /* * 判断该文件是否为图片 */ private boolean isImg(File f) { String postfix = f.toString().substring(f.toString().length()-3, f.toString().length()); Iterator<String> it = imgPatternList.iterator(); while(it.hasNext()) { String file = it.next(); if(file.equalsIgnoreCase(postfix)) { return true; } } return false; } /* * 打开文件 */ private void openFile() { dialog.setVisible(true); if(dialog.getFile() != null) { imgList.removeAll(imgList); fileDir = dialog.getDirectory(); files = new File(fileDir).listFiles(); if(!this.isImg(new File(dialog.getFile()))) { JOptionPane.showMessageDialog(this, "不支持所选图片格式！请重新选择"); } else { img = tk.getImage(fileDir + dialog.getFile()); } // 把所有属于图片的放在一个集合里 for(int i=0; i<files.length; i++) { if(files[i].isFile()) { if(this.isImg(files[i])) { //System.out.println(files[i]); imgList.add(files[i].toString()); } } } amount = imgList.size(); // 找出当前图片所在顺序位置 for(int i=0; i<imgList.size(); i++) { if(imgList.get(i).equals(fileDir+dialog.getFile())) { indexOfNow = i; } } } } /* * 退出程序 */ private void exit() { System.exit(0); } /* * 显示关于程序对话框 */ private void showAboutDialog() { JOptionPane.showMessageDialog( this, "一个简单的照片查看器" + "\n" + "by TracySilocean", "关于", JOptionPane.INFORMATION_MESSAGE, new ImageIcon(PictureViewer.class.getClassLoader().getResource( "0.gif"))); } /* * 显示上一张图片 */ private void lastImg() { if(dialog.getFile() != null) { if(indexOfNow<=0) { //JOptionPane.showMessageDialog(this, "已是第一张！"); indexOfNow = imgList.size() - 1; } else { indexOfNow -= 1; } if(imgList.size() != 0) { img = tk.getImage(imgList.get(indexOfNow)); } } } /* * 显示下一张图片 */ private void nextImg() { if(dialog.getFile() != null) { if(indexOfNow>=imgList.size()-1) { //JOptionPane.showMessageDialog(this, "已是最后一张！"); indexOfNow = 0; } else { indexOfNow += 1; } if(imgList.size() != 0) { img = tk.getImage(imgList.get(indexOfNow)); } } } /* * 删除图片 */ private void deleteImg() { int type = JOptionPane.showConfirmDialog(this, "确定要删除这张图片吗？", "删除文件", JOptionPane.YES_NO_OPTION); if(type == 0) { new File(imgList.get(indexOfNow)).delete(); imgList.remove(indexOfNow); if(indexOfNow>=imgList.size()-1) { indexOfNow = 0; } img = tk.getImage(imgList.get(indexOfNow)); } else if(type == 1) { // 不做任何处理 } } /* * 显示图片属性对话框 */ private void showPropertyDialog() { PropertyDialog propertyDialog = new PropertyDialog(this); propertyDialog.setVisible(true); } public static void main(String[] args) { pv = new PictureViewer(); } /* * 显示图片的panel */ private class MyPanel extends JPanel implements MouseListener { public MyPanel() { this.addMouseListener(this); new Thread(new PaintThread()).start(); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); if(dialog.getFile() != null) { if(pv.isImg(new File(dialog.getFile()))) { pv.setTitle("照片查看器—" + new File(imgList.get(indexOfNow)).getName()); } //g.drawString("正在加载……", 450, 270); lCount.setText("共" + amount + "张" + "，当前第" + (indexOfNow+1) + "张"); int width = img.getWidth(null); int height = img.getHeight(null); int centerX = (mp.getWidth()-width)/2; int centerY = (mp.getHeight()-height)/2; double scale1 = (double)width/(double)height; double scale2 = (double)mp.getWidth()/(double)mp.getHeight(); // 根据图片尺寸按需显示图片 if(width>=mp.getWidth() && height<=mp.getHeight()) { g.drawImage(img, 0, (mp.getHeight()-(height*mp.getWidth()/width))/2, mp.getWidth(), height*mp.getWidth()/width, null); } else if(width<=mp.getWidth() && height>=mp.getHeight()) { g.drawImage(img, (mp.getWidth()-(width*mp.getHeight()/height))/2, 0, width*mp.getHeight()/height, mp.getHeight(), null); } else if(width>=mp.getWidth() && height>=mp.getHeight()) { if(scale1<scale2) { g.drawImage(img, (mp.getWidth()-(width*mp.getHeight()/height))/2, 0, width*mp.getHeight()/height, mp.getHeight(), null); } else { g.drawImage(img, 0, (mp.getHeight()-(height*mp.getWidth()/width))/2, mp.getWidth(), height*mp.getWidth()/width, null); } } else { g.drawImage(img, centerX, centerY, null); } } else { pv.setTitle("照片查看器"); img = tk.getImage(PictureViewer.class.getClassLoader().getResource("bg.png")); g.drawImage(img, 0, 0, mp.getWidth(), mp.getHeight(), null); } } /* * 不断刷新图片面板的线程 */ class PaintThread implements Runnable { @Override public void run() { while(true) { repaint(); try { Thread.sleep(20); } catch (InterruptedException e) { e.printStackTrace(); } } } } @Override public void mouseReleased(MouseEvent e) { if(dialog.getFile() != null) { if(e.getButton() == MouseEvent.BUTTON3) { pm.show(e.getComponent(), e.getX(), e.getY()); } } } @Override public void mouseClicked(MouseEvent e) { // TODO Auto-generated method stub } @Override public void mousePressed(MouseEvent e) { // TODO Auto-generated method stub } @Override public void mouseEntered(MouseEvent e) { // TODO Auto-generated method stub } @Override public void mouseExited(MouseEvent e) { // TODO Auto-generated method stub } } @Override public void keyPressed(KeyEvent e) { int key = e.getKeyCode(); switch(key) { case KeyEvent.VK_UP: case KeyEvent.VK_LEFT: this.lastImg(); break; case KeyEvent.VK_DOWN: case KeyEvent.VK_RIGHT: this.nextImg(); break; } } @Override public void keyTyped(KeyEvent e) { // TODO Auto-generated method stub } @Override public void keyReleased(KeyEvent e) { // TODO Auto-generated method stub } }import java.awt.GridLayout;import java.io.File;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import javax.swing.JDialog;import javax.swing.JLabel;public class PropertyDialog extends JDialog { PictureViewer mf = null; JLabel lName = new JLabel("", JLabel.CENTER); JLabel lSize = new JLabel("", JLabel.CENTER); JLabel lLocation = new JLabel("", JLabel.CENTER); JLabel lLength = new JLabel("", JLabel.CENTER); JLabel lTime = new JLabel("", JLabel.CENTER); File f = null; public PropertyDialog(PictureViewer mf) { f = new File(mf.imgList.get(mf.indexOfNow)); this.mf = mf; this.setLayout(new GridLayout(5, 1)); this.add(lName); this.add(lSize); this.add(lLocation); this.add(lLength); this.add(lTime); lName.setText("名称："+ f.getName()); lSize.setText("图片尺寸：" + mf.img.getWidth(null) + "X" + mf.img.getHeight(null) + " 像素（宽X高）"); lLocation.setText("位置：" + f.getAbsolutePath()); lLength.setText("文件大小：" + f.length()/1024 + "KB"); lTime.setText("修改时间：" + this.getTime()); this.setBounds(500, 300, 400, 200); } public String getTime() { Calendar c = Calendar.getInstance(); long lastTime = f.lastModified(); c.setTimeInMillis(lastTime); Date d = c.getTime(); SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd hh:mm"); return sdf.format(d); } }