JAVA第五次作業，java第五次

JAVA第五次作業，java第五次

老師，沒有弄懂，就參考同學import java.awt.Color;import java.awt.BorderLayout;import java.io.File;import java.awt.Container;import java.awt.event.ActionEvent;import java.util.ArrayList;import java.util.List;import javax.swing.JComboBox;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JList;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.JTextArea;public class FileUtils extends JFrame{    /**     * 列出指定檔案夾（目錄）中的所有檔案或目錄的名額     * @param dri File類型指定的檔案夾（目錄）     * @throws IllegalAccessException      */      public static String listDirectory(File dir) throws IllegalAccessException{          if(!dir.exists()){        throw new IllegalAccessException("目錄"+dir+"不存在");          }                    //判斷dir下關聯的檔案和目錄是否存在          if(!dir.isDirectory()){              //如果不存在拋出異常              throw new IllegalAccessException(dir + "不是目錄");          }          String[] fileName = dir.list();          String name ="";          for(String a : fileName){              name=name+a+"\n";}           return name;          }             /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub         // TODO Auto-generated method stub        JFrame frame=new JFrame();        JPanel main_panel =new JPanel(new BorderLayout());        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //frame.setLayout(null);        String[] itme =new String[]{".jpg",".zip",".doc"};        JComboBox box=new JComboBox();        for(int i=0;i<itme.length;i++){            box.addItem(itme[i]);        }        box.setEnabled(true);        box.setEditable(true);        box.setMaximumRowCount(6);        box.setBounds(230,30,130,25);                      frame.setBounds(400,300,400,200);        frame.setVisible(true);        JTextArea main_text =new JTextArea();        main_text.setBackground(Color.BLACK);        JScrollPane AA=new JScrollPane();        AA.setViewportView(main_text);        main_text.setEnabled(false);        main_panel.add(box,BorderLayout.NORTH);        main_panel.add(AA,BorderLayout.CENTER);        frame.add(main_panel);                                 try {            String str=FileUtils.listDirectory(new File("C:\\Users\\Administrator\\Desktop\\Java作業5\\soundPlayer\\audio"));            main_text.setText(str);        }        catch (IllegalAccessException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    frame.setBounds(300,400,300,400);    frame.setVisible(true);        }}