passing text from JDialog to JFrame

[Arnold Charming]

Hi!

I'm new to this forum and also quite new to Java.
I'm just playing around with it and came to a problem. I have a Jrame window width JDialog popping out of it when user click on a Jbutton. But now I want to send some text from JDialog to Jframe. How to do this? I've tried several things but no luck Help is needed!

[Jez Nicholson]

Quick route is to use JOptionPane to create your dialogs and it will return values.

String inputValue = JOptionPane.showInputDialog("Please input a value");

see the javadoc for more examples. http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/JOptionPane.html

if you need to use JDialog directly then you might have to add a PropertyChangeListener. The Java Tutorial can help http://java.sun.com/docs/books/tutorial/uiswing/components/dialog.html

[Arnold Charming]

Hi!

I'm not quite sure this is what I'm looking for. In my JDialog, a user has to click a button to send text to parent window (JFrame). Text is then displayed inside a JLabell. It tried something like this (this is in JDialog class):

jLabel1.setText("Bla Bla");

jLabel1 is defined on JFrame. This code is executed when someone clicks on a button inside JDialog.

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class DialogCommunication
{
    static JLabel label;    // member variable
 
    public static void main(String[] args)
    {
        JButton launch = new JButton("launch dialog");
        launch.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                launchDialog();
            }
        });
        JPanel north = new JPanel();
        north.add(launch);
        label = new JLabel();
        label.setHorizontalAlignment(JLabel.CENTER);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(north, "North");
        f.getContentPane().add(label, "South");
        f.setSize(200,140);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private static void launchDialog()
    {
        final JDialog dialog = new JDialog(new Frame(), "enter text", false);
        final JTextField textField = new JTextField(16);
        JPanel north = new JPanel();
        north.add(textField);
        JButton send = new JButton("send text");
        send.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String text = textField.getText();
                label.setText(text);
                dialog.dispose();
            }
        });
        JPanel south = new JPanel();
        south.add(send);
        dialog.getContentPane().add(north, "North");
        dialog.getContentPane().add(south, "South");
        dialog.setSize(200,140);
        dialog.setLocation(200,350);
        dialog.setVisible(true);
    }
}

Another option is to send the label reference along to the launchDialog method. The changes for this are:

//    static JLabel label;
 
    public static void main(String[] args)
    {
        final JLabel label = new JLabel();    // local variable
        ...
                launchDialog(label);
        ...
//        label = new JLabel();
    ...
    private static void launchDialog(final JLabel label)

This keeps label out of class scope, ie, label is now a local variable instead of a member variable.

[Jez Nicholson]

Yep.

The choice between instantiating a JDialog or getting it from JOptionPane is about how fancy your dialog needs to be....

import java.awt.event.*;
import javax.swing.*;
 
public class DialogCommunication
{
private JLabel label;    // member variable

public DialogCommunication()
{
JButton launch = new JButton("launch dialog");
launch.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
launchDialog();
}
});
JPanel north = new JPanel();
north.add(launch);
label = new JLabel();
label.setHorizontalAlignment(JLabel.CENTER);
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(north, "North");
f.getContentPane().add(label, "South");
f.setSize(200, 140);
f.setLocation(200, 200);
f.setVisible(true);
}
 
private void launchDialog()
{
String inputValue = JOptionPane.showInputDialog("enter text");
label.setText(inputValue);
}
 
public static void main(String[] args)
{
new DialogCommunication();
}
}

[Arnold Charming]

Hi!

The greenhorn is back
I don't know in which GUI editor you built this but my Jbuilder X Foundation is not the same. The Borland makes for every different frame ,dialog it's own class file. Because my Jdialog in is dialog1.class and main frame is in Frame1.class I can't access to variables that are in Frame1.class. How can do this? Does Java support some cained of a global variable? One more thing. What editors do you guys use? Don't tell me, you're writting your GUI code by hand?

[Arnold Charming]

Hi!

I put static before JLabel and it works. But somehow am confused if this is the right way. Can somehow confirm this?

[Mike Southgate]

To pass info from a dialog back to it's parent frame, what I do is instatiate the jdialog, show it, hide it (this is in the listener for the jdialog's done button). It's important not to dispose of the dialog but only hide it. That way when your jframe gets controll back it can just call a public getter method that you wrote as part of your dialog. You can dispose of the dialog after that.

ms

[Craig Wood]

One of the fun ares in java is in how you put things together. How will your two classes communicate/work together. To launch the dialog in the DialogClass your JFrame class needs a reference (dialogClass in the demo below) to the DialogClass. So how do you get the text back to the JFrame class once the dialog is launched from within the DialogClass? In the code below the DialogClass uses it's new reference to the caller, ie, the DialogCommunication reference dialogCommunication that was passed in through it's constructor, to send the text back to the JFrame class.

There are many ways to put this together. With practice and experimentation we each find our own favorite ways. The main thing is to get the info moved without exposing too much in the process.

And yes I write code by hand in a text editor.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class DialogCommunication extends JFrame
{
    DialogClass dialogClass;
    JLabel label;
 
    public DialogCommunication()
    {
        dialogClass = new DialogClass(this);
        JButton launch = new JButton("launch dialog");
        launch.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                dialogClass.showDialog();
            }
        });
        JPanel north = new JPanel();
        north.add(launch);
        label = new JLabel();
        label.setHorizontalAlignment(JLabel.CENTER);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(north, "North");
        f.getContentPane().add(label, "South");
        f.setSize(200,140);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    public void setLabelText(String text)
    {
        label.setText(text);
    }
 
    public static void main(String[] args)
    {
        new DialogCommunication();
    }
}
 
class DialogClass
{
    DialogCommunication dialogCommunication;
    JDialog dialog;
 
    public DialogClass(DialogCommunication dc)
    {
        dialogCommunication = dc;
        createDialog();
    }
 
    private void createDialog()
    {
        dialog = new JDialog(dialogCommunication, "enter text", false);
        final JTextField textField = new JTextField(16);
        JPanel north = new JPanel();
        north.add(textField);
        JButton send = new JButton("send text");
        send.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String text = textField.getText();
                dialogCommunication.setLabelText(text);
                dialog.dispose();
            }
        });
        JPanel south = new JPanel();
        south.add(send);
        dialog.getContentPane().add(north, "North");
        dialog.getContentPane().add(south, "South");
        dialog.setSize(200,140);
        //dialog.setLocation(200,350);
        dialog.setLocationRelativeTo(dialogCommunication);
    }
 
    public void showDialog()
    {
        dialog.setVisible(true);
    }
}