Hello, I try to rename file or directory using JFileChooser() and JButton(). But it gives me a NullPointer exeption.
I have FileChooser, Button and TextField where I write new name for my file or directory. Can you say where I go wrong and how to solve this problem.

        // button action
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {

                String newFileName = textField.getText();
                // exeption here
                File oldFile = new File(fileChooser.getSelectedFile(), null);
                File newFileOrDirectoryName = new File(newFileName);

                if (oldFile.renameTo(newFileOrDirectoryName)) {
                    System.out.println("renamed");
                } else {
                    System.out.println("Error");
                }

            }
        });

This is a full code:

package ua.edu.lp;

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JFileChooser;

public class App {

    private JFrame frame;
    private JTextField textField;
    private JFileChooser fileChooser;

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    App window = new App();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });

    }

    public App() {
        initialize();
    }

    public void initialize() {
        frame = new JFrame();
        frame.getContentPane().setFont(new Font("Tahoma", Font.BOLD, 14));
        frame.setBounds(100, 100, 539, 469);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);
        frame.getContentPane().setBackground(new Color(255, 246, 143));

        JLabel label = new JLabel("Rename file or package");
        label.setFont(new Font("Tahoma", Font.BOLD, 14));
        label.setHorizontalAlignment(SwingConstants.LEFT);
        label.setBounds(10, 0, 302, 32);
        frame.getContentPane().add(label);

        JLabel label_1 = new JLabel("New file/package name");
        label_1.setHorizontalAlignment(SwingConstants.LEFT);
        label_1.setFont(new Font("Tahoma", Font.BOLD, 14));
        label_1.setBounds(10, 358, 194, 25);
        frame.getContentPane().add(label_1);

        textField = new JTextField();
        textField.setBounds(10, 387, 179, 32);
        frame.getContentPane().add(textField);
        textField.setColumns(10);

        JButton button = new JButton("Rename");
        button.setFont(new Font("Tahoma", Font.BOLD, 14));
        button.setBounds(199, 384, 151, 34);
        button.addActionListener(null);
        frame.getContentPane().add(button);

        fileChooser = new JFileChooser();
        fileChooser.setBounds(10, 51, 505, 289);
        frame.getContentPane().add(fileChooser);

        // button action
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {

                String newFileName = textField.getText();
                File oldFile = new File(fileChooser.getSelectedFile(), null);
                File newFileOrDirectoryName = new File(newFileName);

                if (oldFile.renameTo(newFileOrDirectoryName)) {
                    System.out.println("renamed");
                } else {
                    System.out.println("Error");
                }

            }
        });

    }
}

Edited 1 Year Ago by andruluchko

Looks like you are missing the call to showOpenDialog to make the file chooser do its stuff

Edited 1 Year Ago by JamesCherrill

This article has been dead for over six months. Start a new discussion instead.