java第五次作业

Posted 2020-07-06

import javax.swing.JScrollPane;

 public class FileList extends JFrame{
private static final String FILES_DIR = "audio";
private JList fileList; 

public FileList(){
    super("FileList");
    String[] fileNames = findFiles(FILES_DIR, null);
    makeFrame(fileNames);
    // TODO Auto-generated constructor stub
}

private void makeFrame(String[] autoNames) {
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    JPanel contentPane = (JPanel)getContentPane();
    fileList = new JList(autoNames);
    fileList.setForeground(new Color(140,171,226));
    fileList.setBackground(new Color(0,0,0));
    fileList.setSelectionBackground(new Color(87,49,134));
    fileList.setSelectionForeground(new Color(140,171,226));
    JScrollPane scrollPane = new JScrollPane(fileList);        
    scrollPane.setColumnHeaderView(new JLabel("files list"));
    contentPane.add(scrollPane, BorderLayout.CENTER);
    
    pack();
    // place this frame at the center of the screen and show
    Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
    setLocation(d.width/2 - getWidth()/2, d.height/2 - getHeight()/2);
    setVisible(true);
}

private String[] findFiles(String dirName, String suffix) {
    File dir = new File(dirName);
    if(dir.isDirectory()) {
        String[] allFiles = dir.list();
        if(suffix == null) {
            return allFiles;
        }
        else {
            List<String> selected = new ArrayList<String>();
            for(String filename : allFiles) {
                if(filename.endsWith(suffix)) {
                    selected.add(filename);
                }
            }
            return selected.toArray(new String[selected.size()]);
        }
    }
    else {
        System.out.println("Error: " + dirName + " must be a directory");
        return null;
     }
}

/**
 * @param args
 */
public static void main(String[] args) {
    new FileList();
 }

   }