Develop Reference

how to make jpanel in jframe visible

I try to write a menue for a little game in Java. I thought it would be a good idea to have a Window class (extending JFrame) and then put a JPanel in it for the different Screens (Menue, Game, GameOver etc)
If I put the buttons and stuff directly in the JFrame everything is shwown correct, but when I try to put a JPanel into the JFrame it doesn't work. Here is the code:
public class Window extends JFrame{
private final int WIDTH = 800;
private final int HEIGTH = 600;
private final int QUADRAT = 50;
JButton startButton;
JButton exitButton;
JButton anleitungButton;
JLabel gameTitle;
public Window() {
super("Study Run");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(null);
setSize(WIDTH, HEIGTH);
setResizable(false);
getContentPane().add(new MenuePanel());
setVisible(true);
setLocationRelativeTo(null);
}
And this is my Panel:
public class MenuePanel extends JPanel{
JButton startButton;
JButton exitButton;
JButton anleitungButton;
JLabel gameTitle;
public MenuePanel() {
super();
setBackground(Color.CYAN);
gameTitle = new JLabel("StudyRun", SwingConstants.CENTER);
gameTitle.setBounds(200, 25, 400, 75);
gameTitle.setFont(new Font("Arial", Font.ITALIC, 36));
add(gameTitle);
startButton = new JButton("start");
startButton.setBounds(325, 125, 150, 50);
add(startButton);
anleitungButton = new JButton("anleitung");
anleitungButton.setBounds(325, 200, 150, 50);
add(anleitungButton);
exitButton = new JButton("exit");
exitButton.setBounds(325, 450, 150, 50);
add(exitButton);
CloseListener closeListener = new CloseListener();
StartListener startListener = new StartListener();
AnleitungListener anleitungListener = new AnleitungListener();
startButton.addActionListener(startListener);
anleitungButton.addActionListener(anleitungListener);
exitButton.addActionListener(closeListener);
}
The only help I found online was, that I needed to add the panel before I set the frame visible. That didn't work. Putting pack() or revalidate() anywhere in the code didn't work either. Also setting the Panel on opaque or visible didn't do anything. I don't know what else to try?!

Your problem is here:
setLayout(null);
When you use null layouts, you the coder are completely responsible for the location and size of all added components. Your added component has no size and so defaults to 0, 0.
A (bad) solution: give the MenuePanel a size or bounds
A much better solution: learn and use the layout managers (as all your searches most assuredly already told you).

It's best to remember that Java uses Flowlayout() as a default.
public Window() {
setLayout(new FlowLayout());
}
So your basically overwriting the layout to null as explained in the previous answer.Also if you plan to use different class and panels to add to a JFrame from different classes use a getter
class SomePanel{
public JComponent getPanel(){
return panel;
}
}
Then add to JFrame..
class MyFrame{
add(new SomePanel().getPanel());
}

Java Open a new window by clicking a button

Been sitting here at my computer for about 13 hours and I think my eyes are bleeding.
I found a little gui editor I love called GuiGenie.
It works perfect for creating the window with the buttons and all that good stuff.
The problem is i want to click a button in my first menu and have it open my other menu i made.
I just starting programming 4 weeks ago so I'm a complete noob.
I have a feeling its messing up because of the main methods but I have no idea and 13 hours of sitting here trying millions of things is making me go crazy : )
here is what i got so far
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class MyPanel extends JPanel {
private JTextField How;
private JLabel jcomp2;
private JLabel jcomp3;
private JButton jcomp4;
public MyPanel() {
//construct components
How = new JTextField (1);
jcomp2 = new JLabel ("How long were you parked?");
jcomp3 = new JLabel ("Minutes");
jcomp4 = new JButton ("openNewWindow");
//adjust size and set layout
setPreferredSize (new Dimension (315, 85));
setLayout (null);
//add components
add (How);
add (jcomp2);
add (jcomp3);
add (jcomp4);
//set component bounds (only needed by Absolute Positioning)
How.setBounds (245, 50, 60, 25);
jcomp2.setBounds (35, 30, 185, 50);
jcomp3.setBounds (250, 30, 60, 20);
jcomp4.setBounds (0, 0, 315, 25);
jcomp4.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
}
});
}
public static void main (String[] args) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel());
frame.pack();
frame.setVisible (true);
}
}
When the button is pressed, I want it to open this new window
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class MyPanel2 extends JPanel {
private JButton jcomp1;
private JButton jcomp2;
private JButton jcomp3;
private JTextField jcomp4;
public MyPanel2() {
//construct components
jcomp1 = new JButton ("test1");
jcomp2 = new JButton ("test2");
jcomp3 = new JButton ("test3");
jcomp4 = new JTextField (5);
//adjust size and set layout
setPreferredSize (new Dimension (395, 156));
setLayout (null);
//add components
add (jcomp1);
add (jcomp2);
add (jcomp3);
add (jcomp4);
//set component bounds (only needed by Absolute Positioning)
jcomp1.setBounds (20, 45, 100, 25);
jcomp2.setBounds (135, 60, 100, 25);
jcomp3.setBounds (260, 35, 100, 25);
jcomp4.setBounds (105, 115, 100, 25);
}
public static void main (String[] args) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel2());
frame.pack();
frame.setVisible (true);
}
}
If anyone could help I would appreciate it greatly!!
I have a lot of respect for you pros out there because if you are a pro at this, you are probably smarter than 99.9% of the world.
This stuff hurts my brain.

Here is something you can do, for this situation, where you have multiple Forms or Windows what you can do is to use a JPanel which can have this CardLayout set as it's LayoutManager and then you can add the two JPanels to it and access them with the methods provided by the same.
Don't use setBounds() when using Absolute Positioning this is really not the right way of putting components to the parent container. Instead use setLocation(...) and setSize(...) methods. Consider not to use Absolute Positioning as much as possible for you. Certain lines in favour of the before said line taken from Java Docs are as follows :
Although it is possible to do without a layout manager, you should use a
layout manager if at all possible. A layout manager makes it easier to
adjust to look-and-feel-dependent component appearances, to different
font sizes, to a container's changing size, and to different locales.
Layout managers also can be reused easily by other containers, as well as
other programs.
Since the output of your program is really not a soothing experience in any sense. Atleast LayoutManager, can make that work a lot more easier for you, since you need not have to specify position and size for each and every component. Try walking through the Layout Mangers Tutorials, and get accustomed to them as soon as possible. They are the real life savers :-)
Here is a modified code taken from your SOURCE CODE
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class CardLayoutExample
{
private JPanel contentPane;
private MyPanel panel1;
private MyPanel2 panel2;
private void displayGUI()
{
JFrame frame = new JFrame("Card Layout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setBorder(
BorderFactory.createEmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new CardLayout());
panel1 = new MyPanel(contentPane);
panel2 = new MyPanel2();
contentPane.add(panel1, "Panel 1");
contentPane.add(panel2, "Panel 2");
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new CardLayoutExample().displayGUI();
}
});
}
}
class MyPanel extends JPanel {
private JTextField How;
private JLabel jcomp2;
private JLabel jcomp3;
private JButton jcomp4;
private JPanel contentPane;
public MyPanel(JPanel panel) {
contentPane = panel;
//construct components
How = new JTextField (1);
jcomp2 = new JLabel ("How long were you parked?");
jcomp3 = new JLabel ("Minutes");
jcomp4 = new JButton ("openNewWindow");
//adjust size and set layout
setPreferredSize (new Dimension (315, 85));
setLayout (null);
//set component bounds (only needed by Absolute Positioning)
How.setBounds (245, 50, 60, 25);
jcomp2.setBounds (35, 30, 185, 50);
jcomp3.setBounds (250, 30, 60, 20);
jcomp4.setLocation(0, 0);
jcomp4.setSize(315, 25);
jcomp4.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.next(contentPane);
}
});
//add components
add (How);
add (jcomp2);
add (jcomp3);
add (jcomp4);
}
}
class MyPanel2 extends JPanel {
private JButton jcomp1;
private JButton jcomp2;
private JButton jcomp3;
private JTextField jcomp4;
public MyPanel2() {
//construct components
jcomp1 = new JButton ("test1");
jcomp2 = new JButton ("test2");
jcomp3 = new JButton ("test3");
jcomp4 = new JTextField (5);
//adjust size and set layout
setPreferredSize (new Dimension (395, 156));
setLayout (null);
//set component bounds (only needed by Absolute Positioning)
jcomp1.setBounds (20, 45, 100, 25);
jcomp2.setBounds (135, 60, 100, 25);
jcomp3.setBounds (260, 35, 100, 25);
jcomp4.setBounds (105, 115, 100, 25);
//add components
add (jcomp1);
add (jcomp2);
add (jcomp3);
add (jcomp4);
}
}

Here is the code for myPanel class, use this one:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class MyPanel extends JPanel {
private JTextField How;
private JLabel jcomp2;
private JLabel jcomp3;
private JButton jcomp4;
public MyPanel() {
//construct components
How = new JTextField (1);
jcomp2 = new JLabel ("How long were you parked?");
jcomp3 = new JLabel ("Minutes");
jcomp4 = new JButton ("openNewWindow");
jcomp4.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel2());
frame.pack();
frame.setVisible (true);
}
});
//adjust size and set layout
setPreferredSize (new Dimension (315, 85));
setLayout (null);
//add components
add (How);
add (jcomp2);
add (jcomp3);
add (jcomp4);
//set component bounds (only needed by Absolute Positioning)
How.setBounds (245, 50, 60, 25);
jcomp2.setBounds (35, 30, 185, 50);
jcomp3.setBounds (250, 30, 60, 20);
jcomp4.setBounds (0, 0, 315, 25);
jcomp4.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
}
});
}
public static void main (String[] args) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel());
frame.pack();
frame.setVisible (true);
}
}

How to place an object in a specific location (x,y) on a JFrame?

How can I place an object in a specific location (x,y) on a JFrame?

Here find the Absolute Positioning Tutorials. Please do read carefully, as to why this approach is discouraged over using LayoutManagers
To add say a JButton to your JPanel, you can use this :
JButton button = new JButton("Click Me");
button.setBounds(5, 5, 50, 30);
panel.add(button);
Here try this example program :
import java.awt.*;
import javax.swing.*;
public class AbsoluteLayoutExample
{
private void displayGUI()
{
JFrame frame = new JFrame("Absolute Layout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setOpaque(true);
contentPane.setBackground(Color.WHITE);
contentPane.setLayout(null);
JLabel label = new JLabel(
"This JPanel uses Absolute Positioning"
, JLabel.CENTER);
label.setSize(300, 30);
label.setLocation(5, 5);
JButton button = new JButton("USELESS");
button.setSize(100, 30);
button.setLocation(95, 45);
contentPane.add(label);
contentPane.add(button);
frame.setContentPane(contentPane);
frame.setSize(310, 125);
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new AbsoluteLayoutExample().displayGUI();
}
});
}
}

Try these 2... in combination with each other...
setLocation() and setBounds()
Its even better to use GroupLayout, developed by NetBeans team in 2005. WindowsBuilder Pro is a good tool for Building Gui in java

Check out this absolute layout code sample:
Absolute Layout demo

In the class inheriting the frame:
setLayout(null);
In your component:
setLocation(x,y);

My whole code is complete but I am not able to add a second button

Please take a look at my code it is working fine the way I want but the only issue is that I want to add another button opposite my current button and I am not able to do so can any body please help me.
import java.awt.event.*;
import javax.swing.*;
public class Example2 extends JFrame {
public Example2() {
initUI();
}
public final void initUI() {
JPanel panel = new JPanel();
getContentPane().add(panel);
panel.setLayout(null);
panel.setToolTipText("A Panel container");
JButton button = new JButton("Even");
button.setBounds(100, 60, 100, 30);
button.setToolTipText("A button component");
JButton button2 = new JButton("Odd");
button2.setBounds(100, 60, 100, 30);
button2.setToolTipText("A button component");
//Add action listener to button
button.addActionListener(new ActionListener () {
public void actionPerformed(ActionEvent e)
{
//Execute when button is pressed
System .out.println("You clicked the button");
int sum=0;
for(int i=1;i<=100;i++){
if(i%2==0){
System.out.println(i);
sum+=i;
}
}
System.out.println("Sum of even numbers: "+sum);
}
});
panel.add(button);
panel.add(button2);
setTitle("Tooltip");
setSize(500, 400);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args) {
Example2 ex = new Example2();
ex.setVisible(true);
}
}

panel.setLayout(null);
That is where it starts to go wrong.
Use layouts. See Laying Out Components Within a Container & Effective Layout Management: Short Course for more details.
Use:
The appropriate layouts.
Possibly nested inside one another.
With appropriate layout padding and component border/insets for white space.
As an aside.
...
button.setBounds(100, 60, 100, 30);
button.setToolTipText("A button component");
JButton button2 = new JButton("Odd");
button2.setBounds(100, 60, 100, 30);
...
Did you notice how the bounds of the two buttons were identical? What do you think happens when you put two components of the same size in the same place?

You have to change panel.setLayout(null) to layout you need. For example:
panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));
or
panel.setLayout(new java.awt.FlowLayout(java.awt.FlowLayout.CENTER));

Andrew Thompson +1 ,
Here are some usefull links :
A Visual Guide to Layout Managers
Using Layout Managers
Adding space between components

JTextField uneditable in JWindow

I have a Jwindow, and when I added a Jtextfield to it, the textfield became uneditable.
JWindow window = new JWindow();
window.setBounds(400, 100, 700,500);
window.setVisible(true);
window.setLayout(null);
JTextField text = new JTextField();
text.setBounds(300, 300, 150, 30);
text.setEditable(true);
window.getContentPane().add(text);
But when I tried to use Jframe as Jwindow's owner, the textfield was now editable, but the frame showed up together with the jwindow :
JFrame frame = new JFrame();
frame.setVisible(true);
JWindow window = new JWindow();
window.setBounds(400, 100, 700,500);
window.setVisible(true);
window.setLayout(null);
JTextField text = new JTextField();
text.setBounds(300, 300, 150, 30);
text.setEditable(true);
window.getContentPane().add(text);
So, I have 2 questions :
Why JTextField is uneditable in JWindow and how could I make it editable?
What is the main purpose of using JFrame as JWindow's border?

EDIT,
contents of JWindow is accesible only if its parent is displayed on the screen
for editable and accesible contents use un_decorated JDialog instead of JWindow, jDialog doesn't caused non_accesible contents,
reason why ..., I can't explain, not undestand why, no way in this moment, the API says me nothing about caused accesible, editable ...
.
.
.
1. Why JTextField is uneditable in JWindow and how could i let it able to edit?
really don't know
import java.awt.*;
import javax.swing.*;
public class WindowTest {
private JFrame frame;
public JPanel createContentPane() {
JTextField text = new JTextField("Whatewer");
JPanel panel = new JPanel();
panel.add(text);
createAndShowWindow();
return panel;
}
void createAndShowGUI() {
frame = new JFrame("Window Test");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setContentPane(createContentPane());
frame.setLocation(50, 50);
frame.pack();
frame.setVisible(true);
}
private void createAndShowWindow() {
JTextField text = new JTextField("Whatewer");
JWindow win = new JWindow(frame);
win.setLayout(new GridLayout(0, 1));
win.add(text);
win.pack();
win.setLocation(150, 50);
win.setVisible(true);
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
public void run() {
new WindowTest().createAndShowGUI();
}
});
}
}
EDIT
Yes, both are editable, and i wannt only JWindow to be displayed. Thanks!!
by default JWindow required JFrame for correct workaround
nobody tell that this JFrame must be visible (valid for GUI), then remove these code lines from frame.setDefaultClose.... including frame.setVisible(true); from my example
in this form current JVM instance never gone from RAM, untill your PC restarted or swith off, you have to add separated exit JButton with code line System.exit(0) inside ActionListener

The JWindow should be focusable. Use public void setFocusable(boolean focusable) method.