Adding JPanel to JFrame

[BEHROUZ]

Hi Every one,
I am new at java swing and I am trying to add a Jpanel to my frame. I
have three simple class as below
1-Class MyPanel
2-Class MyFrame
3-Class Main
I did my best to add the panel to my frame but it did not work! Could
you please let me know what I am doing wrong!?
//=====================
1.
2. package mypaneltest;
3. import javax.swing.JButton;
4. import javax.swing.JPanel;
5.
6. public class MyPanel extends JPanel {
7. public MyPanel(){
8. JPanel pan = new JPanel();
9. JButton okButton = new JButton("OK");
10. pan.add(okButton);
11. }
12. }
13. //=====================
14. package mypaneltest;
15. import javax.swing.JFrame;
16.
17. public class MyFrame extends JFrame {
18. public MyFrame(){
19. super("Test");
20. setSize(300,200);
21. setLocationRelativeTo(null);
22. MyPanel pane = new MyPanel();
23. add(pane);
24. }
25. }
26. //======================
27. package mypaneltest;
28.
29. public class Main {
30. public static void main(String[] args) {
31. new MyFrame().setVisible(true);
32. }
33. }

Best Regards

 

[RedGrittyBrick]

2. package mypaneltest;
3. import javax.swing.JButton;
4. import javax.swing.JPanel;
5.
6. public class MyPanel extends JPanel {
7. public MyPanel(){
8. JPanel pan = new JPanel();
9. JButton okButton = new JButton("OK");
10. pan.add(okButton);

Note pan is a separate instance of JPanel from that constructed by MyPanel

Delete 8. and replace 109 with
add(okButton)


Note that your should also construct your GUI on the EDT - you will
have problems later if you don't.

You should also pack() your JFrame.

11. }
12. }
13. //=====================
14. package mypaneltest;
15. import javax.swing.JFrame;
16.
17. public class MyFrame extends JFrame {
18. public MyFrame(){
19. super("Test");
20. setSize(300,200);
21. setLocationRelativeTo(null);
22. MyPanel pane = new MyPanel();
23. add(pane);
24. }
25. }
26. //======================
27. package mypaneltest;
28.
29. public class Main {
30. public static void main(String[] args) {
31. new MyFrame().setVisible(true);
32. }
33. }

It's good that you provided the full code that illustrates your problem.
It's bad that you added line numbers. I couldn't immediately see what
was causing your problems and the line numbers prevent me using
cut&paste to put your code into a Java compiler.


Here's how I'd have written it

---------------------8<--------------------------
package org.redgrittybrick.test.swing;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class MyPanelTest {
/**
* @author: RedGrittyBrick
*/

public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MyPanelTest().createAndShowGUI();
}
});
}

private void createAndShowGUI() {
JPanel p = new JPanel();
p.add(new JButton("OK"));

JFrame f = new JFrame("Test");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(p);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
---------------------8<--------------------------

 

[BEHROUZ]

    2. package mypaneltest;
    3. import javax.swing.JButton;
    4. import javax.swing.JPanel;
    5.
    6. public class MyPanel extends JPanel {
    7. public MyPanel(){
    8.     JPanel pan = new JPanel();
    9.     JButton okButton = new JButton("OK");
   10.     pan.add(okButton);

Note pan is a separate instance of JPanel from that constructed by MyPanel

Delete 8. and replace 109 with
    add(okButton)

Note that your should also construct your GUI on the EDT - you  will
have problems later if you don't.

You should also pack() your JFrame.

   11. }
   12. }
   13. //=====================
   14. package mypaneltest;
   15. import javax.swing.JFrame;
   16.
   17. public class MyFrame extends JFrame {
   18. public MyFrame(){
   19.      super("Test");
   20.      setSize(300,200);
   21.      setLocationRelativeTo(null);
   22.   MyPanel pane = new MyPanel();
   23.   add(pane);
   24. }
   25. }
   26. //======================
   27. package mypaneltest;
   28.
   29. public class Main {
   30.     public static void main(String[] args) {
   31.          new MyFrame().setVisible(true);
   32.     }
   33. }

It's good that you provided the full code that illustrates your problem.
It's bad that you added line numbers. I couldn't immediately see what
was causing your problems and the line numbers prevent me using
cut&paste to put your code into a Java compiler.

Here's how I'd have written it

---------------------8<--------------------------
package org.redgrittybrick.test.swing;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class MyPanelTest {
     /**
      * @author: RedGrittyBrick
      */

     public static void main(String[] args) {
         SwingUtilities.invokeLater(new Runnable() {
             public void run() {
                 new MyPanelTest().createAndShowGUI();
             }
         });
     }

     private void createAndShowGUI() {
         JPanel p = new JPanel();
         p.add(new JButton("OK"));

         JFrame f = new JFrame("Test");
         f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         f.add(p);
         f.pack();
         f.setLocationRelativeTo(null);
         f.setVisible(true);
     }}

---------------------8<--------------------------

Thanks,
I got it now, but what is EDT?
**Note that your should also construct your GUI on the EDT - you will
have problems later if you don't.**
could you please tell me more?

 

[Lew]

I got it now, but what is EDT?
**Note that your should also construct your GUI on the EDT - you will
have problems later if you don't.**
could you please tell me more?

This is covered in the Swing tutorial, which you should have read and should
read now. In particular, the EDT is covered in:
<http://java.sun.com/docs/books/tutorial/uiswing/concurrency/index.html>

See also:
<http://www.google.com/search?q=Java+EDT>
or
<http://www.google.com/search?q=Java+"Event+Dispatch+Thread">

GIYF.

 

[Roedy Green]

It's good that you provided the full code that illustrates your problem.
It's bad that you added line numbers. I couldn't immediately see what
was causing your problems and the line numbers prevent me using
cut&paste to put your code into a Java compiler.

Visual SlickEdit is great for this. You just drag a rectangle with
the right mouse button and hit delete. Intellij has column mode -- not
quite so convenient, but great for doing things like stripping off
line numbers.

I do all kinds of data manipulation tasks using just the column, sort
and regex search replace features of Slick Edit. It saves writing
reams of one-shot code.
--
Roedy Green Canadian Mind Products
http://mindprod.com

Nothing has really happened until it has been recorded.
~ Virginia Woolf (born: 1882-01-25 died: 1941-03-28 at age: 59)

 

[Roedy Green]

1-Class MyPanel
2-Class MyFrame
3-Class Main

see http://mindprod.com/jgloss/jframe.html
http://mindprod.com/jgloss/jpanel.html
--
Roedy Green Canadian Mind Products
http://mindprod.com

Nothing has really happened until it has been recorded.
~ Virginia Woolf (born: 1882-01-25 died: 1941-03-28 at age: 59)

 

[Arne Vajhøj]

Visual SlickEdit is great for this. You just drag a rectangle with
the right mouse button and hit delete. Intellij has column mode -- not
quite so convenient, but great for doing things like stripping off
line numbers.

I do all kinds of data manipulation tasks using just the column, sort
and regex search replace features of Slick Edit. It saves writing
reams of one-shot code.

UltraEdit can edit rectangular.

Arne

 

[Lew]

UltraEdit can edit rectangular.

So can emacs. So can vi. So can Textpad. So can eclipse with a plugin.
There used to be a plugin for NetBeans but I'm not finding it right now.