Accessing JTextField using a private class

Question

I'm trying to store output from user inputed text, this is simply a template for it but I can't seem to figure out a way to properly access the JTextArea, all the examples I've found are doing it in a different way then I'm trying to accomplish it, is it possible to do it this way?

import javax.swing.*;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.*;

public class HelloWorldSwing {
private JFrame mainFrame;
private JLabel headerLabel;
private JLabel statusLabel;
private JPanel controlPanel;


public HelloWorldSwing(){
    prepareGUI();
}
public static void main(String[] args){
    HelloWorldSwing swingControlDemo = new HelloWorldSwing();
    swingControlDemo.showEventDemo();
}
private void prepareGUI(){
    mainFrame = new JFrame("Java Swing Demo");
    mainFrame.setSize(400,400);
    mainFrame.setLayout(new GridLayout(3,1));

    headerLabel = new JLabel("",JLabel.CENTER);
    statusLabel = new JLabel("",JLabel.CENTER);
    statusLabel.setSize(350,100);

    mainFrame.addWindowFocusListener(new WindowAdapter() {
        public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
        }
    });
    controlPanel = new JPanel();
    controlPanel.setLayout(new FlowLayout());

    mainFrame.add(headerLabel);
    mainFrame.add(controlPanel);
    mainFrame.add(statusLabel);
    mainFrame.setVisible(true);
}
private void showEventDemo(){
    headerLabel.setText("Control in action: Button");


    JButton submitButton = new JButton("Submit");
    JTextField userTextField = new JTextField("all",26);

    submitButton.setActionCommand("Submit");

    submitButton.addActionListener(new ButtonClickListener());

    controlPanel.add(userTextField);
    controlPanel.add(submitButton);

    mainFrame.setVisible(true);

}

private class ButtonClickListener implements ActionListener {
    @Override
    public void actionPerformed(ActionEvent e){
        JTextField textField = (JTextField) e.getSource();
        String text = textField.getText();
        statusLabel.setText(text);

    }
}

}

score 2 · Accepted Answer · answered Jul 11 '17 at 16:20

First, move the showEventDemo() code into the setup GUI (because that's still setting up the GUI).

You have a class called ButtonClickListener which is listening to a JButton object, receiving ActionEvents that originate from a JTextField. This is not a sensible approach, because the ActionEvent is only going to have a source of the JButton you added it to as a listener.

Instead, you need to rewrite your listener. You could create a constructor for it, passing in the JTextField.

private class StatusUpdateListener implements ActionListener {
    private JTextField input;
    private JLabel status;

    public SubmitButtonListener(JTextField source, JLabel dest) {
       input = source;
       status = dest;
    }

    public void actionPerformed(ActionEvent e){
        String text = input.getText();
        status.setText(text);
    }
}

Then it would be used some where like

submitButton.addActionListener(new StatusUpdateListener(userTextField, statusLabel));

@user7381012 Glad to help. Don't be afraid of treating your ActionListeners as classes that help you solve your problems. Careful work to make the reusable, and you can promote them to be public classes (and use them multiple times through out a project). — Edwin Buck, Jul 11 '17 at 18:17

Accessing JTextField using a private class

1 Answers1