MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.File;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.filechooser.FileFilter;

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

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        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 MainClass("FileChooser Demo");
    }
}

class TextFilter extends FileFilter {

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