If a checkbox checked in class1 and settext texfield in class2 ?

Question

1.00/5 (1 vote)

See more:

I create these classes with netbeans Jframe form. I put a checkbox and a button in class1 and a textfield in class2.

I want to sent a text to the textfield in class2 with class1. I don't recieve error but code isn't work. Could you help me for fix it? Thanks.

Java

package test;
public class class1 extends javax.swing.JFrame {
public class1() {
    initComponents();
}

@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents()...                        

public void sent(class2 theOtherClassInstance) {
    if (jCheckBox1.isSelected()) {
        theOtherClassInstance.jTextField1.setText("That's it"); // this jtextfield in the class2
    }
}

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    class2 theOtherClassInstance = new class2();
    sent(theOtherClassInstance);

    this.setVisible(false);
    new class2().setVisible(true);
}                                        

public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new class1().setVisible(true);
        }
    });
}
// Variables declaration - do not modify                     
private javax.swing.JButton jButton1;
private javax.swing.JCheckBox jCheckBox1;
// End of variables declaration                   
}

This is the class2:

Java

package test;
public class class2 extends javax.swing.JFrame {
    public class2() {
        initComponents();
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents()...                       

    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new class2().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    public javax.swing.JTextField jTextField1;
    // End of variables declaration                   
}

Posted 8-Jan-16 7:39am

bugsoul

Updated 8-Jan-16 20:31pm

v4

Add a Solution

Comments

Sergey Alexandrovich Kryukov 8-Jan-16 14:14pm

Not clear. You never explained what is classB...
Your progress in English is impressive, and, if Java is very complicated for you, just learn it to make it easy. :-)
—SA

bugsoul 9-Jan-16 2:35am

Thanks for suggestion Sergey. But I can't learn with easy things. I can learn just like project only:) I put my whole code. If you look at it, I'll be very happy. Thanks.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Richard Deeming · Answer 1 · 2016-01-08T08:34:00

Solution 1

At a guess, jtextfield is defined as an instance member of the class classB, but you're trying to access it like a class (static) member.

This is a common problem for users coming from VB.NET, since VB.NET creates a default instance of your Form classes for you, and makes them available as global variables with the same name as the class. (So Form1.TextBox1 accesses the control on the default instance of the Form1 class.) This was done for backwards-compatibility with VB6, and always causes confusion for people moving to a different language!

You'll need an instance of the class in order to access the instance members:

Java

public first(classB theOtherClassInstance) {
    initComponents();
    if (jCheckBox1.isSelected()) {
        theOtherClassInstance.jtextfield.setText("That's it !");
    }
}

NB: It always helps if you post the error message you're getting. :)

Posted 8-Jan-16 8:34am

Richard Deeming

Comments

bugsoul 8-Jan-16 15:04pm

Thanks Richard, this time that error appered;
"jtextfield has private access in classB"

Maybe I have to use a button click event,

Richard Deeming 8-Jan-16 15:06pm

That just means that jtextfield is declared as private. Change it to public, and the code should work.

bugsoul 8-Jan-16 15:16pm

OK I understand. Thanks. Netbeans don't access me for change initComponents(). I'll find the solution.

bugsoul 8-Jan-16 15:38pm

I change the public and add button event but unfortunately it isn't work.

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
classB theOtherClassInstance = null;
first(theOtherClassInstance);
}

Richard Deeming 8-Jan-16 15:41pm

You're passing in null as the instance of classB. You need to pass in the actual instance of the class that you want to update.

bugsoul 8-Jan-16 15:45pm

Netbeans is automaticly write "null". Could you please give an example.

Richard Deeming 8-Jan-16 15:47pm

If you want to update a new instance of the class:

classB theOtherClassInstance = new classB();
first(thisOtherClassInstance);

If you want to update an existing instance of the class, then you'll have to retrieve that from somewhere. How you do that depends on how that existing instance was created in the first place.

bugsoul 8-Jan-16 16:33pm

No error but no result. Anyway thank you so much. I try again tomorrow.

bugsoul 9-Jan-16 2:38am

Hi, Richard. I did try and search again but I can't again. I put my whole code. Could you please look at it again.

Richard Deeming 11-Jan-16 8:38am

You seem to have two main methods, which looks a bit odd.

The last line in your jButton1ActionPerformed method creates another new instance of class2, and makes it visible. That second new instance won't have the text field set, because you set that on a different instance.

Try changing the last line of that method to:
theOtherClassInstance.setVisible(true);