filechooserdemo.java

来自「java 完全探索的随书源码」· Java 代码 · 共 91 行

// FileChooserDemo.java

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.filechooser.*;

import java.awt.event.*;

import java.io.File;

class FileChooserDemo extends JFrame implements ActionListener
{
   FileChooserDemo (String title)
   {
      super (title);

      addWindowListener (new WindowAdapter ()
                         {
                             public void windowClosing (WindowEvent e)
                             {
                                System.exit (0);
                             }
                         });

      JPanel p = new JPanel ();

      JButton jb = new JButton ("Open ...");
      jb.addActionListener (this);
      p.add (jb);

      jb = new JButton ("Save ...");
      jb.addActionListener (this);
      p.add (jb);

      getContentPane ().add (p);

      setSize (200, 65);
      setVisible (true);
   }

   public void actionPerformed (ActionEvent e)
   {
      int retVal;

      JFileChooser fc = new JFileChooser ();

      if (e.getActionCommand ().equals ("Open ..."))
      {
          fc.addChoosableFileFilter (new TextFilter ());
          retVal = fc.showOpenDialog (this);
      }
      else
          retVal = fc.showSaveDialog (this);

      if (retVal == JFileChooser.APPROVE_OPTION)
          System.out.println (fc.getSelectedFile ().getName ());
   }

   public static void main (String [] args)
   {
      new FileChooserDemo ("FileChooser Demo");
   }
}

class TextFilter extends FileFilter
{
   // Accept all directories and txt files.

   public boolean accept (File f)
   {
      if (f.isDirectory ())
          return true;

      // Check extension for txt.

      String s = f.getName ();
      int i = s.lastIndexOf ('.');

      if (i > 0 && i < s.length () - 1)
          if (s.substring (i + 1).toLowerCase ().equals ("txt"))
              return true;

      return false;
   }
    
   public String getDescription ()
   {
      return "Accepts txt files only.";
   }
}