第一个Java程序,简单的打开图片并显示在面板上
代码如下:
1 import java.awt.Component; 2 import java.awt.EventQueue; 3 import java.awt.Graphics; 4 import java.awt.event.*; 5 import java.io.*; 6 import javax.swing.*; 7 8 public class HelloWorld { 9 10 /** 11 * @param args 12 */ 13 public static void main(String[] args) { 14 // TODO Auto-generated method stub 15 EventQueue.invokeLater(new Runnable() { 16 17 @Override 18 public void run() { 19 // TODO Auto-generated method stub 20 JFrame frame = new ImageViewerFrame(); 21 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 22 frame.setVisible(true); 23 } 24 }); 25 } 26 } 27 28 class ImageViewerFrame extends JFrame{ 29 public ImageViewerFrame(){ 30 setTitle("ImageViewer"); 31 setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); 32 label = new JLabel(); 33 add(label); 34 chooser = new JFileChooser(); 35 chooser.setCurrentDirectory(new File(".")); 36 JMenuBar menubar = new JMenuBar(); 37 setJMenuBar(menubar); 38 JMenu menu = new JMenu("File"); 39 menubar.add(menu); 40 JMenuItem openItem = new JMenuItem("Open"); 41 menu.add(openItem); 42 JMenuItem exitItem = new JMenuItem("Close"); 43 menu.add(exitItem); 44 openItem.addActionListener(new ActionListener() { 45 46 @Override 47 public void actionPerformed(ActionEvent arg0) { 48 // TODO Auto-generated method stub 49 int result = chooser.showOpenDialog(null); 50 if(result == JFileChooser.APPROVE_OPTION){ 51 String name = chooser.getSelectedFile().getPath(); 52 label.setIcon(new ImageIcon(name)); 53 } 54 } 55 }); 56 exitItem.addActionListener(new ActionListener() { 57 58 @Override 59 public void actionPerformed(ActionEvent arg0) { 60 // TODO Auto-generated method stub 61 System.exit(0); 62 } 63 }); 64 } 65 private JLabel label; 66 private JFileChooser chooser; 67 private static final int DEFAULT_WIDTH = 300; 68 private static final int DEFAULT_HEIGHT = 400; 69 }
显示效果如下: