在《JAVA核心编程》中,有一段这样的代码
import javax.swing.*;
import java.awt.*;
import java.io.File;
public class ImageViewer {
public static void main(String[] args){
EventQueue.invokeLater(() -> {
JFrame frame = new ImageViewerFrame();
frame.setTitle("ImageViewer");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
class ImageViewerFrame extends JFrame{
private JLabel label;
private JFileChooser chooser;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 400;
public ImageViewerFrame(){
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
label = new JLabel();
add(label);
chooser = new JFileChooser();
chooser.setCurrentDirectory(new File("."));
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JMenu menu